Captain InterStellar

Some thoughts for 2012

2012-01-07T19:41:00.002+11:00

Haven't posted for a while so better put something up! Wishing everyone clear skies and smooth waters for the year. What is the difference between Mathematics and Physics? Picked up this interesting quote which is food for thought:

"We are able to demonstrate geometrical matters because we make them; if we could prove physical matters we would be able to make them".

Giovanni Vico (1668-1744).

What's happening with Propulsion Physics and where are we going? Is Interstellar Travel going to happen sometime soon? Several interesting papers were published in 2011 and the 100 year Starship conference went ahead however don't see them leading to a breakthrough anytime soon. Several key technologies such as fusion reactors need to be in place before the propositions in the papers can be turned into a Starship so one might have to wait at least 50 years, Marc has his wonderings on a possible future timelime here. It appears that the Universe as we understand it with our current models is not human friendly as far as practical interstellar flight is concerned although the Physics doesn't deny us Interstellar Travel, it appears that one needs to be prepared for the extreme challenges of distances and time required to travel to possible nearby Earth-like planets in our Galaxy.

If Schiller's Strand model for eg turns out correct, then it looks like Physics is close to being complete which would make it even more difficult for Breakthrough Propulsion Physics. Between work, I am pursuing my studies for 2012 in Quantum Vacuum Physics & Engineering and see where it leads. The other big problem is getting large amounts of hardware into orbit without using chemical rockets. Is there a viable solution without using space elevators?

Some recents photos taken when I was recently in Exmouth, Western Australia. Most interesting sites are the US Navy VLF transmitter for submarines and the Learmonth Solar Observatory. Didn't see any turtles laying eggs on the beach, they turn up at night.

CI.

Local Exmouth resident.

Vlamming Head Lighthouse.

Navy VLF station in the distance.

Closer view.

Checkout the Sydney outline diagram!

An interstellar position fixing method

2011-06-28T12:45:00.001+10:00

Paper is now available for download at:

http://vixra.org/abs/1106.0053

CI.

Here goes Captain PlakaDuck

2011-06-13T23:06:00.000+10:00

Any day on the water is better than a good day at the office!

Introduction to Wärtsilä marine diesel engines

2011-05-09T02:44:00.002+10:00

Been reading up quite a bit on these engines as recently I've been working on a OSV (Offshore Supply Vessel) as 1st Engineer and this boat was particularly interesting since it's the first time I've worked on one which has Z-pellers and introduced me to Wärtsilä marine diesel engines which are famous for their slow to medium speed engines used in big ships. This one had two Wärtsilä 6R25, 4-stroke 6 cylinder inline turbocharged air start main engines rated at 1493KW each, these are classed as medium speed diesel engines which means they don't go over 1000RPM. There's another engine just to run the fire pump and also has three 471 Detroits for the generators, quite a busy engine room as far as maintenance goes as there are lots of other machinery to look after in and out of the engine room which includes a fuel clarifier, oily water separator, compressed air system, sewage treatment plant, hydraulic system, air conditioning plant etc.

The engine room, port main engine in the background

Big engine

From the outside the engine looks fairly simple design compared to Caterpillar and Cummins engines I'm used to work with, these have much less pipework running around the engine and each cyclinder has a pyrometer to check exhaust temperatures. As is common practice with large engines, the indicator cocks are opened for each cylinder and compressed air run through them at first to blow out any water or fuel. This is to make sure there's nothing blocking the pistons upon startup which could cause damage. The other thing that striked me is that there are no batteries used in the engine room as everything including the generators are started with compressed air (couple of new batteries which haven't been commissioned yet have been introduced purely for a new upcoming electronic Z-peller control system).

Front of the main engine

If for some reason one has to leave a dead ship on a cyclone mooring for eg, one makes sure that the two compressed air bottles are pressed up before shutting down and failing that there is a manual air pump with a large handle to get compressed air in an emergency for startup which will need at least 800 pumps, good workout!

Being a manned engine room, this one has an airconditioned Engineer's control room which is really cool :-) The shafting behind the main engines leading to the aft compartment which has the machinery for the Z-pellers is quite extensive with 7 shaft bearings on each side and mechanical joints throughout the system. As this system allows the propellers to be rotated 360° in azimuth, this makes the vessel highly manoeuvrable and is used quite often in tugboats and other vessels.

Many large ships these days use Azipods which are similar in principle except they use a large electric motor underneath the ship to drive a propeller in direct drive. This is a more efficient system as the electric motors generate 100% torque at 0 RPM (unlike conventional diesel engines) and the diesel generators producing the electrical power to drive these Azipods can now be placed anywhere in the ship thus giving the ship designer more flexibility because the engine room doesn't have to be aft of the ship anymore with long shafts saving space for more cargo. Since the motors are electric, this also opens up the doors to using future technologies such as Hydrogen fuel cells, nuclear power plants etc which also produce electrical power without burning fossil fuels (was watching a doco the other day which indicated we reached peak oil production in 2006!).

Very cool Engineer's control room

Starboard Z-peller control system

It's coming up to 3am here, better start doing my rounds so till next time.

BTW for those who didn't know LyX 2.0 has just been released! Looks like they've made major upgrades, check it out. Writing a paper called "A position fixing method in Interstellar Space" using Lyx, keep you people posted.

CI.

iPhone application development adventures

2011-02-16T21:41:00.005+11:00

Just a few months ago after walking past an Apple store (the flashy new one in Sydney CBD) I decided to go in and have a wonder around and play with the toys they had displayed. Since I was a kid, I've always been a PC person myself and the thought of using an Apple computer would send shivers down my spine... I always liked the idea I could goto the monthly computer market and get bits and pieces of computer hardware, memory etc and build my own computer and tinker around with it. My first one (8088) didn't even have a case, the computer power supply, motherboard, 5 1/2 inch floppy drive (remember them?) all were sitting on the table next to the black&green monitor and clunky keyboard typing away programs in BASIC and playing flight simulator in MSDOS! Anyway had a look at Apple's hardware and played around with the iPhone 4.

I was thinking getting a new phone because the one I had was cleary outdated and the battery in my one was starting to get old. Well I was sold! Well sort off. Although the phone looked great, I was more interested in the iPhone applications that run on it and was pretty impressed especially since the phone packs a dummy GPS, motion sensors, camera etc. I didn't want to fork out the $800 or so they wanted so decided to get an iPhone 3GS from ebay at a more reasonable price to experiment. I was hooked! How do these people write all these great games and applications? Although I have experience writting in Java, one needs to learn Objective C for iPhone stuff so got myself copies of Objective-C for Dummies and iPhone Application Development for Dummies. All good so far except to develop iPhone Apps, one needs the Apple Software Development Kit which apparently only runs on Mac computers!

Mmmmm I had no choice then and saw the sleek looking MacBook Pro and grabbed one from the Apple store! To be able to test and download my Apps on a real iPhone and download the Software Development Kit, one must sign up to become a registered Apple Developer and pay the fee. While looking at the other Apps in the iTunes store one will notice that many developers will write a "HD" ie High Definition version of their game for the iPad. Well after playing around with it and realised I wouldn't have to printout all these Physics PDFs so I can read them on the run, got an iPad as well! I was pretty impressed with the iBooks application apart from the quality games and Apps people have written for it. One can also get whole physics lectures in iTunes U.

Well after getting all this Apple hardware, am I a convert? Definately not, however for reading I will definately be using my IPad from now on as the screen is large enough to make reading PDFs easy on the go and the MacBook for App development.

So what's coming up? Well, I'm working on my first iPhone/iPad game which shall be called Deckhand Pro: Sydney. This will have lots of maritime action and test your rope throwing skills onto the wharf, battling through misbehaving passengers, rescuing Man Overboards, rescuing boats stuck on reefs, stopping dissembarking passengers from taking beer bottles and drinks with them etc should be great fun. Other apps I have in mind include an iPhone Maritime Tutor for Master 5 and MED 3 students getting ready for their orals and a compass error calculator. So is writting all this fun? U betya! :-)

CI.

Some more photos from Western Australia where I was working as Engineer on a cargo boat.

This is home for 5 weeks, on a cyclone mooring here near Dampier.

It's pretty hot in here, not too bad once you get used to it.

Nuts and bolts

2011-02-04T11:33:00.013+11:00

It has been an interesting start of the year for 2011 with some recent items worth mentioning:

Marc Millis of the Tau Zero Foundation posted two papers related to interstellar flight:

Progress in revolutionary Propulsion Physics: summarises the current state of where we stand towards a solution? for "timely interstellar flight - to reach other habitable worlds within a human lifespan". There are currently many options available to reach other stars using known physics. Most would take many decades just to reach our neighbour stars and none of them can get us to destinations beyond many light-years away in a timely, human lifespan timeframe. The paper uses many references from the first recent textbook devoted to this area of research and is worth every dollar: Frontiers of Propulsion Science. I like Figure 1 in the paper which graphically shows the many areas of Physics and concepts that need further research grouped by the key barriers to practical interstellar flight as stated in the paper: Non-propellant propulsion, faster than light travel and energy breakthroughs.

Second paper by Marc: Energy, incessant obsolescence, and the first interstellar missions: there's a review here. Regarding the "incessant obsolescence postulate: No matter when an interstellar probe is launched, a subsequent probe will reach the destination sooner and with more modern equipment": better launch as soon as one has the capabilities to do so because the opportunity may not present itself again due to unforseen circumstances in the future or "societal retardation" ie unforseen catastrophies or less energy production. The implicit motivations for interstellar flight, Table 6 in the paper is interesting, apart from the obvious scientific benefits from the mission and safeguarding humanity's long term survival, I liked another reason that Marc mentions in his talk to pursue interstellar flight: it gives nations something to conquer peacefully and together rather than concentrating on conquering each other on Earth.

Significant results released by the Kepler space telescope shows possible candidates for other Earth like planets. From the NASA press release:

"The fact that we’ve found so many planet candidates in such a tiny fraction of the sky suggests there are countless planets orbiting stars like our sun in our galaxy," said Borucki. "Kepler can find only a small fraction of the planets around the stars it looks at because the orbits aren’t aligned properly. If you account for those two factors, our results indicate there must be millions of planets orbiting the stars that surround our sun."

Also checkout APOD, Centauri Dreams, this and this.

Got in the mail a few days ago: Advanced Propulsion Systems and Technologies, Today to 2020. Another major problem to practical interstellar flight is getting the expected large amounts of hardware out of Earth's gravity well into orbit without using chemical rockets. Space elevators have been proposed (which seems only viable if ultra high strength carbon nanotube cables can be commercially fabricated in the required lengths). A more elegant solution? from Space Drive Physics is worth looking into (see Marc's first paper for an introduction, Chapter 3 Prerequisites for Space Drive Science and Chapter 12 Thrusting against the Quantum Vacuum in Frontiers of Propulsion Science). Anyway should be an interesting read.

CI.

Fremantle Harbour, Western Australia.

Dampier Harbour, Western Australia.

Book Review: And Yet It Moves

2010-12-06T23:05:00.006+11:00

Today I finished reading And Yet It Moves: strange systems and subtle questions in Physics by Mark P. Silverman. I found this book particularly interesting as it introduced me to quantum phenomenon which previously weren't very familiar to me. The author being a research physicist has first hand experience with the topics he discusses. Several experiments are descibed including the wave like propagation of electrons in the two-slit experiment describing the familiar wave interference effect and the Aharonov-Bohm effect and other subtle behaviour of electrons. To me the nature of this particle is somewhat still not understood. Some texts for example will describe the electron as point-like as today's experiments give no measurable size of this particle (the classical electron radius is given as 10^-13 cm), however there is no such thing as a point-like entity (and no such as thing as a mathematical singularity in nature for that matter which rules out infinities as well, the Universe is not infinite) so suffice to say the electron must have a size albeit very small and unmeasurable with current technology.

The author goes on to describe some exotic atoms describing some which can be nearly the size of bacteria!, the physics of light reflections, light polarisation, the Mach-Zehnder interferometer, the amazing (check this out!) Vortex Tube and other interesting subtle effects. The author asks on p204:

"Can the rotation of the Earth influence the structure of an atom?"

And goes on to discuss biomolecular chirality ie why living things make and use specific types of molecules such as right-handed sugar molecules or left-handed amino acids (this isn't understood, Earth evolutionary reasons?). The last chapter "Science and wonder" gives a personal account on various issues with science education, from the last page:

"To teach science well, one must have the philosophical attitudes of a scientist: to see science as culturally important, technically useful and aesthetically moving; to understand that the pursuit and acquisition of scientific knowledge helps free the mind from the bondage of ignorance, superstition and prejudice; to have a driving curiosity to comprehend the reason that manifests itself in nature and to enjoy sharing this curiosity with others.

Einstein's eloquent words say it all:

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. He who knows it not and can no longer wonder, no longer feel amazement, is as good as dead, a snuffed-out candle."

Great book, definately recommend reading it, got me chasing up some of the references at the back as well.

Red Bull Flugtag 2010 photos

2010-12-01T15:46:00.002+11:00

A few weeks ago we had the judges onboard for the Red Bull Flugtag event in Farm Cove near the Sydney Opera House. Those crazzy people with their flying machines were at it again! It was a nice sunny day and there was a good turnup with the crowds and boats.

One of the teams made quite a long flight (it was pretty much a standard flying kite though, no exotic design). Most just fell straight down off the ramp to see their flying machine broken into bits and pieces. The judges gave scores to each team for design, asthetics etc.

After the crew are rescued by Surf Rescue, what happens to these flying machines?

Although few teams have demonstrated their mastery of flight, it was a fun day out on the water.

CI.

A day out on a 100 tonnes mobile slewing crane

2010-11-13T09:33:00.001+11:00

I recently finished a course at Botany Cranes to get a WorkCover 100 tonnes mobile slewing crane licence (for work reasons on boats). Because I was the only one in the class, they sent me with one of the crane drivers for a day for a dual lift job to see first hand the operations of the crane and get some dogging experience. I thoroughly enjoyed the course and more importantly passed the big test at the end. The crane I went on was a Liebherr 100 tonnes crane who make some of the best cranes in the world. The other crane that came with us was the 130t crane. A support truck and crew is also needed for the cranes to carry additional hook blocks, counterweights, packing for the outriggers etc.

Leaving the yard from Botany Bay our destination was the P&O container depot near Bankstown to put together an Omega Megastacker crane (brand new) which is used to lift and move shipping containers.

The Cranes

The job

After a toolbox meeting with the other crew, the cranes are parked into position and outriggers for the cranes extended to maintain stability of the crane during lift. Timber packings are used under the outrigger pads to spread the weight of the crane over a larger surface area onto the ground. All the wheels of the crane must be above ground and the crane dead horizontal. There is an electronic equivalent of a spirit level which makes this process fairly straightforward.

Setting up the outriggers

The crane operator will decide what hook blocks are required for the job, what hook radius he will be operating (and hence how much boom needs to be blown out) and more importantly how much the load mass with all lifting gear such as spreader beams need to be included. The crane operator reads the Load Chart for the crane which gives all this important information and will decide how much counterweight needs to be placed at the rear of the crane. All these factors will dictate what the maximum load the crane can lift for those parameters. With the boom fully extended, this crane would tip over if the operator forgets to place counterweights on the crane. The Liebherr cranes have an onboard computer which also makes all this process straightforward and safe (we don't want the crane to be tipping over or brake the $2.5 mil crane!). The more the boom is blown out or the more the boom is lowered for a given boom length, the less the crane can lift.

After unhooking the hook block at the front of the crane and setting up the counterweights, the crane operator blows out the necessary boom sections. Everything is hydraulically operated and one selects from the computer screen how much boom we want. Two heavy hauler trucks turned up with the Megastacker's boom and arms, nice $20000 paintwork!

The first truck looks like a Transformer in disguise? ;-)

After both cranes are setup and the truck with the first part of the Megastacker in position, the dogmen setup the chain slings required for the job. One person will direct the crane operators for the dual lift job. This is a delicate operation and both cranes need to work together so no extra stress is placed on the cranes and lifting gear. The first part of the job required the boom section of the Megastacker to be placed into position so the Omega technicians could pop in the holding pins for the boom. Once this was done hydraulic rams needed to be lifted and bolted on both sides. The position of the boom had to be in perfect alignment otherwise the pins wouldn't go in.

Putting the million dollar Megastacker together

After the boom section and rams were secured, the next part of the job was to lift and attach the grabber (which grabs and locks into the containers). This was also a delicate operation. Hydraulic rams needed also to be lifted and bolted into position.

The grabber section for the Megastacker

By late afternoon the job was finished and it was time to pack up the gear and stow the cranes for road travel. Because of the tare weight of these cranes, they aren't allowed to travel on some bridges (including Sydney Harbour bridge), tunnels etc so he needs to have a good read of a street directory to decide what is the best route to get to and from a job. We make it back to the Botany Cranes yard after heavy traffic on the main roads. With all the construction that goes around the city, the other cranes are also out doing jobs.

So there you go, great day out and learnt a lot. If you want to see how big these cranes get, checkout the Liebherr 1200 tonnes mobile slewing crane! (Other crane types get even bigger). Doing the Dogman course at the moment (at another school because of timetable reasons). A Dogman is the person who slings the loads, directs the crane operator etc, big test in a few days so better get back to studying! Till next time.

CI.

Caricature

2010-11-08T13:48:00.001+11:00

Got a visit in the wheelhouse yesterday by Caricaturist Gavin Bell during a cruise in Sydney Harbour (Red Bull Flugtag event photos coming soon). Here it is!

Voyages to Lord Howe Island

2010-10-16T16:04:00.007+11:00

It's been a while since I've updated my blog, been a bit busy with work/new job/studies etc.

Started working on the general cargo vessel MV Island Trader the last several weeks. Doing my 4th trip this coming week. Lord Howe Island is just over 300nm East of Port Macquarie, NSW. The boat delivers everything that a small community of 300 + 400 or so tourists need on the island including diesel for the island's power station, petrol, LPG, A-1 jet fuel for the airport, frozen and refrigerated goods, building materials, cars/trucks, mail and all kinds of other general cargo. The Island Trader departs Port Macquarie usually every second Thursday and on the return trip picks up garbage, return mail, empty fuel drums etc from the island for disposal back on the mainland. A one way trip takes just under 2 days.

The previous day and on the day of departure, the derrick cranes on the boat and forklifts are getting a good workout loading the cargo onboard, crew secure all cargo and make sure everything is well strapped in. Final drafts of the vessel are taken, stability calculations done, cargo gear stowed and secured, final checks done, we then wait for the next high tide to leave port. Leaving the wharf which is a few Kilometers up the Hastings River near the Pacific Highway, we venture downstream past the two cable car ferries that service the Port Macquarie area further down from Dennis Bridge.

Getting to Lord Howe Island is pretty easy, after crossing the bar at Port Macquarie head East and eventually you'll get to the Island. From the island head dead West 270° T to get back to Port Macquarie. There can be busy shipping traffic near the coast but once clear of the coast there is very rarely any vessels in sight after 50nm.

During the trip I typically do regular 4 hour watches on and off as Officer Of the Watch (OOW) in the wheelhouse. The boat is on autopilot so I'm not actually steering the boat in the above photo ;-) however minor course corrections need to be regularly made as the autopilot steers by the steering compass. According to the GPS, our speed over ground is usually around 8Kn however sometimes the ocean currents will make us go slower or faster for our given engines RPM and our SOG can vary from 6.5Kn to 12.5Kn (record so far), big difference! This can affect our ETA to the island significantly to the point where sometimes we can miss the high tide or we would arrive too early which in this case we would slow down during the last leg. There are quite a lot of sea birds visible along the way as well including Albatrosses. Close to the coast we saw the usual migrating whales and dolphins.

Our destination at the island is the wharf constructed in front of the site which used to be the island's flying boat airport terminal when flying boats used to provide regular flights to the island from Rose Bay, Sydney. The island now has a 1Km runway and Qantas provide usually 3 flights a day out from Sydney, Port Macquarie and Brisbane using Dash-8s.

The wharf is inside the lagoon on the western side of the island which is surrounded by reefs however there is a narrow passage for vessels to enter the lagoon marked with transit leads and sector lights. To get to the wharf we also need a high tide and the Lord Howe Island Harbour Master will give us a reading of the current tide at the wharf via VHF radio as the current tide readings can vary depending on weather conditions (such as barometric pressure) compared to predicted tide table readings.

Getting through the channel can get a bit hairy when the sea is a bit rough and the Captain (Master 3) who has lots of local knowledge will decide whether to enter or not. If conditions are too rough to make an entry, the boat can either do circles around the island or drop anchor at a sheltered location till things settle down. Once inside the lagoon the waters are usually pretty calm however at high tide big waves can still go over the surrounding reefs and cause surges in the lagoon.

Once secured at the wharf, the Engineer will start emptying the ballast tanks so the boat sits at the bottom, this makes it safer for cargo unloading however even then one has to be careful with the derrick cranes as at high tide the boat can still surge a bit. There can be quite a large crowd at the wharf apart from the wharf crew, tourists turn up to check out all the maritime action. It will take the rest of the day and the next day to unload all the cargo with the help of the wharf crew who live on the island. Supplies and goods are then delivered to their destinations by several trucks that go throughout the island. The Captain was kind enough to let me off so I could hop on one of the trucks to get a sightseeing drive of the island on my first trip.

The boat usually stays at the island for a couple of days. During those days it's very busy as after all the cargo is unloaded, there is the back load cargo to be taken onboard, stowed and secured. However sometimes we finish a bit earlier in the afternoon and on one trip managed to go for a walk to some other areas on the island. Ned's Beach which is on the eastern side of the island was interesting with big King fish swimming around my legs when I was feeding them nibblies. I also introduced myself to the local cows and went hill hiking to get a better view of the scenery:

There are many resorts on the island and tourism is the main revenue maker and the export of the local Kentia palm tree seeds which is native to the island. There are a few boats that also do diving, fishing and sightseeing trips to Elizabeth and Middleton coral reefs which are located 150Km north-east of the island. These are the southern most coral reefs in Australia. If you venture at night to have a beer at the local bowling club, bring a torch with you because there are no street lights (which is great because you can see the Milky Way, should have brought my telescope with me ;-) There is no mobile phone reception on the island however there is a Telstra public phone available and we can watch TV onboard when we are at the island.

The back load is usually light, skip bins full of garbage, recycled plastic etc, lots of empty 200L A-1 jet fuel drums, empty LPG tanks and IBCs (Intermediate Bulk Containers) for petrol and other stuff. I'm told that the airplanes that land at the island have to always refuel in case they can't land back at their destination and have to be diverted so no one wonder they go through a lot of fuel drums.

Heading back to Port Macquarie is pretty much the same routine with watches and I'm finding sleeping in the bunk with the boat rolling side to side relaxing however the trips that I've done so far haven't been that rough. One of the deckhands onboard cooks dinner for the crew every day and he's a pretty good cook too. The most relaxing part of the job is while we are at sea as in port things get busy and this gives me a chance to catchup on my readings.

On the second day of the return sea voyage we also do an emergency drill such as Man Overboard, Fire drills etc and test equipment. After we are docked at the wharf back at Port Macquarie up the Hastings River all the back load is unloaded and we give the cargo hold and boat a good cleanup and any maintenance required on the cargo gear and boat is carried out. After signing off it's a 5 hour drive for me back to Sydney. Till next time.

CI.

More interesting technology

2010-04-19T20:14:00.000+10:00

Been a bit busy with my studies so no long posts for a while but here's an interesting photo of a touch screen onboard a boat I work on as Engineer ;-)

New T3000 Marine Autopilot

2010-03-23T18:48:00.000+11:00

Just can't keep up with technology these days, what will they think of next? ;-)

Part 8: Book Review - Prospects for Interstellar Travel

2010-02-14T16:06:00.004+11:00

In the final part of this book review series we look at the last chapter where the author gives his conclusions and further thoughts on many of the topics discussed so far and gives some assessments on how far it would be feasible to push technology and possible scientific breakthroughs needed: "If prospects for mastering the ultra-technical problem of interstellar travel in the near future seem somewhat discouraging, this chapter tries to show where we must try harder." so let's have a look.

In the search for better technology based on our laws and theories discovered so far, it is pointed out that: "Science consists partly of revolutions in understanding (e.g. relativity). More revolutions are needed to make interstellar travel easy, although laws of nature are not so much overthrown as refined." [CI: This reminds me of what Roger Penrose said in his book quoted below:]

Mauldin goes on mentioning that very few stones have been left unturned as far as energy sources go. Many of the topics discussed in the book are based on 19th century physics with relativity imposing refinements and limits to travel in the form of lightspeed and mass-energy for propulsion and the Standard Model doesn't appear to have any new undiscovered nuclear energy sources however it is expected that new materials and new uses of electromagnetic fields for eg. will allow progress in many areas such as the possibility of warm superconductors and fusion reactors.

[CI: Image: Example of a proposed reactor to study fusion: ITER.]

To understand Nature, theories are developed to help us describe her and to verify these theories experimental evidence is acquired to see if Nature agrees with them. Many theories are developed however few standup to observational evidence or experiment. [CI: a good quote from Planck below].

[CI: Photo: Our closest star the Sun, a natural fusion reactor.]

The author goes on to mention that: "Whether our science is slowing for lack of startling new evidence, or for lack of deeper, more clever human thinking, or from reaching final barriers inherent in nature cannot be determined. The situation is perplexing. Some would say that scientific progress continues to accelerate, not just applied science but basic science." It is also pointed out that as far as interstellar travel is concerned, this is partly an engineering problem and building a starship would involve assembling materials of the right size, with reliability, performance and cost. This may also mean pushing known materials to their limits. Several examples are then given with a discussion on the current state of affairs regarding superconductors, magnetic fields and materials sciences and their applications to previously discussed power systems, shields and solar sails. The author then mentions some of the current problems we face in science related to interstellar travel:

"Scientifically, the crucial advances are needed first in physics. If powerful propulsion is developed, along with solutions to some of the operations problems, then biological, social, and economic problems of travel would eventually be solved. Those who study interstellar travel in a fascinating blend of fantasy and real physics have found a large number of different ways of getting there, almost all meriting careful theoretical study, none yet leading to affordable hardware even if scientists had ready access to space now. Unfortunetly, there is very little indication in general relativity or elementary particles of new higher energy sources, forces, or effects that could be used in propulsion. If there were, motion in the context of general relativity (curved space-time) would also merit more study and be part of this book."

[CI: Research is ongoing. Regular conferences are also held. For those who wish to study the propulsion aspects further, a good starting point is: Frontiers of Propulsion Science. If you need to brushup on your physics try this free book, these free lecture notes and read this other free book while you're at it. Understanding the physics of the vacuum (and how it affects matter/energy and vice versa) may be an important step in making some progress in this area. Here are some interesting items to get started: 1, 2, 3. Regular news in this field can also be found from Centauri Dreams and keep an eye for the latest papers on arXiv and viXra. Here's a useful guide to sort out the crackpots.]

The author then discusses further the enormous energy requirements for interstellar travel and even with anti-matter we still have the fundamental energy problem: "how to get more energy from less inertial mass." It is pointed out that some studies for eg. have looked into the vacuum with its varying amounts of fluctuating energy mostly as particle/anti-particle pairs and the possibility of harnessing these quanta of energy. Nature allows one to borrow energy without penalty provided this loan is over a very short period of time: "Planck's constant is involved and permits only very tiny effects [see Appendix D]. One could borrow 10^24 J, the whole KE requirement of a star journey, from space itself for about 10^-58 second, an inconveniently short-term loan." with longer time loans one could borrow smaller amounts of energy but for 1 J the loan period would still only be 10^-34 second and this quantum borrowing doesn't appear feasible however notes: "A way to cheat nature on this law is yet to be found. Perhaps it will be overthrown in some subtle, unforseen, dramatic way."

Other areas worth a look where the Stardard Model has left doors open include the possibility for a "false vacuum" field or Higgs field which is thought to be left over from the Big Bang and might be producing the masses for all particles by "resisting" their motion until they enter the TeV energy domain. The Higgs field would make itself known by its Higgs bosons over 1 TeV [CI: one of the goals of the LHC is to detect these particles] and the author gives a rundown of what we think of this Higgs field looking at the cosmological constant considerations and inflation theories. The author suggests further studies into the higher energy domains using space based accelerators may provide some solutions for interstellar drives and notes that: "space has many "vacuum" fields: gravitational, electro-magnetic, hypothesized false vacuum (Higgs), nuclear, and others that may be discovered. All should be ruled by the law of quantum physics in that the amount of energy that temporarily appears is determined by Planck's constant." Studies in the the electromagnetic field of the vacuum have also been ongoing with the Casimir effect. The force on the plates can be made to

[CI: Image: When two metal plates are a few micrometers apart, an attractive Casimir force develops due to an inbalance of the electromagnetic fluctuations in the vacuum between the plates.]

do work that is yield energy however no useful amounts of energy are expected to be extracted using this method. Some consideration is given to "Dark matter" and the author gives a rundown of what is and isn't known so far however notes that: "More discouraging is that the bulk of dark matter, if it exists, seems to be present not within galaxies but in intergalactic space where we cannot use it." All avenues for a possible "ultra-energy" source need investigating, this is directly linked to any future prospects for ultra-relativistic interstellar travel.

A discussion is then given on Back Holes and other interesting phenomena that follow from General Relativity that "greatly distort, disconnect, or connect space-time" such as hypothetical wormholes and whiteholes. Some studies have looked into the possiblities of using these unusual spacetime topologies for interstellar travel and all are highly speculative. The author notes that: "Black Holes are probably real although finding sufficient evidence to be convincing has been a major task. The nearest partly-confirmed one Cygnus X-1 is thousands of lightyears away." Approaching a black hole alone would be very dangerous because of the intense radiation due to infalling material and the large gravitational tidal effects ripping objects apart. Various authors have considered black holes as a possible power source for starships however these appear unrealistic.

Some mention is also given to so called "anti-gravity", "hyderdrives", "spacewarp drives" and Faster-than-light (FTL) ideas which are thought to be either physically unrealistic or highly speculative however notes that General Relativity as currently understood does not prohibit particles moving FTL locally but they cannot move slower than light, these hypothetical particles are called Tachyons. [CI: Many authors have written papers on various spacetime warping schemes however some authors have also shown that these may not be physically possible when one considers quantum effects as well. My point of view is that the highly distorted spacetime topologies are unfeasible when one considers quantum vacuum effects and are at best interesting exercises in General Relativity for considering the various solutions it can offer, not all of which can be used or are allowed in nature.]

In chapter 8 the author discussed the problem of space transport from the starship to the surface of the new planet and vice versa with a discussion of why this would be a problem as there would presumably be no facilities on the new planet (for shuttle launches for eg) and the use of chemical rockets for moving large amounts of materials and personel is expensive and unsuitable for planets larger than Earth (with a deeper gravity well) because of the large amounts of fuel (preferably hydrogen/oxygen) to be carried on the interstellar mission and this would need to be found at the destination. It is also noted that with new planets with an atmosphere, shuttles could glide their way to the surface however for some interesting airless planets these will require rocket landings (and probably would be deficient in fuel). Capsule landings via parachute are not recommended because they only carry small loads and are less likely to be reusable. Abundant hydrogen would still be required even if anti-matter provided the energy.

Mention is given to new designs of spaceplanes which were considered such as the Hermes however these may be difficult to design for unknown atmospheres. All the previous other ideas pointed out on non-rocket space launches (space elevators, launch tracks, balloon supported launches etc) also have their problems and notes that: "As with spaceplanes, most of these methods seem to use materials to their limits in strength, toughness, and/or integrity. At an interstellar destination, most of these involve massive structures which cannot easily be carried or built on site." It is also pointed out that: "At present massive emigration from Earth to local space seems impossible due to the cost and complexity of lifting just the people, never mind their equipment, into space. Transport using cables and the like would change that." It would be necessary to build an extensive infrastructure in the local space environment (for fuel and structures) before landing people on the planet is considered.

[CI: Image: One alternative to using rockets on an airless moon or planet: shoot your
precious cargo off the planet using the eletromagnetic catapult concept?]

Some considerations are also given to the "wilder ideas" such as stronger materials using only neutrons (such as the closely packet matter in neutron stars where the electrons have combined with protons and notes that: "If neutrons did "touch" and bond, nuclear matter would be a trillion times stronger than ordinary everyday matter." and with physicists starting to collect very cold and slow neutrons in bottles the possibility could be explored.

Several interesting conclusions are then given by the author on the various topics discussed throughout the book and makes a note again that: "The key practical step toward the stars is propulsion, but technology is inseparable from purpose." and points out that a trend in the articles published on starship propulsion ideas seem to lean more and more towards lower speeds from the high gammas of 0.9c down to 0.1c (Daedalus) to 0.01c for some fusion drives. The author gives his assessment on propulsion on p303:

"The best guesses here for propulsion at present are sunbeam-pushed sail or pulsed fusion, with a separate braking system. Farther down the list because they are still slower are an ion-drive powered by a fusion reactor, or a solar sail using direct local sunlight."

and notes further along that: "shielding, artificial gee, operating power (especially if sails are used), and landing remain to be solved as discussed earlier." pointing out that a starship with no artificial gee is likely to deny the crew to land on a planet due to the permanent changes this would cause to their bodies.

Further conclusions on the sociopoliticial context are also given. It is pointed out that although there was initial great enthusiasm for the space age, progress has become very slow and: "public support and money seem to have diminished, although US NASA's budget increases year by year. Less and less is done, while some billions of dollars are spent on mistakes." and further along asks:

"Political problems aside, is this the trend of our future in space, less and less over longer and longer time, with perhaps bigger confusion and failures? Have we reached technical limits already? Delays on new propulsion would seem to corroborate this... A yet unimagined drive would drastically change the situation."

It is also pointed out by the author that over the several chapters, many great problems were presented and this all might seem discouraging to future prospects for successful interstellar missions:

"the difficulty of determining a habitable destination before going there, the difficulty of returning, the long ordeal of many generations traveling to a near star, the hazards of breakdowns, radiation, and zero gee, the long time commitment to find out if a mission yields results, and the lack of visitors here who have accomplished such travel. But it is too early in our social and technological history to draw final conclusions about this futuristic goal, and no single paramount conclusion can be presented here. To reach the expected scientific and technical adventures and achievements, we simply may need to try harder."

Given the expected enormous costs of an interstellar mission (given at 100 T$ upwards for a 100 person mission), the author gives his point of view of why interstellar travel should be pursued despite the costs and great technical difficulties:

"The energy, environmental, and monetory costs of launch from Earth already seem almost prohibitive. Some say that we can no longer afford space, that we must work on problems of population control, environment, energy, housing, education, equality, crime, and health at home. Even if these problems were fully and cooperatively addressed, one should still ask, toward what end? Is this all a young civilization can do for the rest of its time, try to hold onto a high quality of life for some and establish a mediocre but adequate quality for the rest? Restricted to one planet, humans at most can try for an ecologically stable or "sustainable" set of "lifestyles", more complex, based on different economics, probably more austere than present varied styles. At best, a garden planet with a lower stable population would result. New frontiers in space can provide direct and symbolic outlets for untamable instincts, places for adventurers to fulfull themselves and initiatives for homebound populations to support at modest levels."

and also makes several conclusions based on human nature as it appears now. Contrary to what is portrayed in science fiction, because of the many difficulties mentioned earlier, very few people would actually get to travel to the stars and interstellar travel cannot also be used to "save" Earth. Sending any useful practical results back to Earth could also take centuries (if one considers a 1000 year mission) and hence interstellar missions would be very difficult politically to implement and most people would have forgotten of the mission over time however: "While the problem of interstellar travel is closely intermeshed with our future, it is an open question whether we can expect a study of interstellar travel to make a difference in the general human condition."

The author concludes by mentioning that the goal of his study and review on interstellar travel was: "to leave the case in the hands of present and future readers with a wide range of interests and let them judge what the prospects are now and later. All options should be set out for contemplation and planning... Interstellar studies as a complex branch of science and technology could serve as one of many inspiring vehicles to teach the spectrum of sciences and applied math, to introduce systems and design, to teach integrated and creative thinking, to show the interaction of technology and society, and much more. Grasping and exploring the problem can engross a student for years. Education in the broadest ways possible is one key to a future that permits interstellar missions."

[CI: In the Appendix sections of the book, the author gives a concise summary of classical physics and relativistic travel with an explanation of the physics behind the various concepts discussed in the book with more detailed mathematical treatment and numerical output tables of the included BASIC programs comparing various values of acceleration, time, gammas, distance traveled etc. The author has also put together an impressive bibliography section.

Although somewhat dated, this was one of the best books on Interstellar Travel I've read and thoroughly enjoyed reading it. I was impressed by the level of detail and information given by the author and highly recommend the book to anyone.]

Part 7: Book Review - Prospects for Interstellar Travel

2010-02-09T20:34:00.002+11:00

In this continuing book review series we look into Chapter 11 where the author reviews the search for other intelligent beings and explores the related issues this has with interstellar travel. Whether life can begin on other planets is still an open question as so far there is no strong evidence to suggest so. The author points out that despite all the research papers published on this subject, conferences held etc, "The work has been informed speculation due to the lack of experimental and observational results". However given what we do know about life here so far, a number of interesting educated guesses can be made on the possibility of life elsewhere.

The Search for Extra-Terrestrial Intelligence (SETI) is a vast subject incorporating many disciplines including: "astronomy (which stars might have planets), planetary studies (which planets might have conditions for life), biology (what sorts of biospheres can evolve on planets), a mix of biology, sociology, and philosophy (what kinds of intelligent beings can arise and how would they act), technology (what means would "they" use to send and receive messages, or themselves, across many lightyears), mathematics (expected to be a common language), and other fields (as we define them). SETI includes Communication with Extra-terrestrial Intelligence (CETI) and can include sending messages as well as receiving them."

Interest on the possibility of other beings has been around for a long time looking back in our history, authors going back from ancient Greece to 16th Century Giordano Bruno for eg. [CI: my favourite quotes from Christiaan Huygens and part of Edward Young's Night Thoughts followed below]

Several terms over the years have been used to refer to extra-terrestrials, such as "ETs" (from the movie), "humanoid" (somewhat assuming human like two legs, two arms and a head) and "aliens" (blood thirsty bug eyed monsters). The author uses the term intelligent beings or simply "beings", implying: "creatures who have evolved to the level of recognizing their own existence and therefore likely to study their place in the Universe ... We assume intelligence also includes rational thinking (which some humans practice some of the time), problem solving, artistic creation, development of science, technical competence (tool use expanded to building, flying, computing, transmitting messages, etc.), complex societies with evolving cultures, and more." The study of life as it might arise elsewhere in different conditions and its evolution not necessarily leading upto intelligent life, is known as exobiology. So far we are only familiar with carbon-based lifeforms as on Earth. Carbon based molecules are very versatile for life however there is no basic proof showing that life cannot use other chemistry .

Mention is made of the Drake equation (shown above) which makes an attempt to predict the number of civilisations in our galaxy at any given time which have achieved technology for radio communications by multiplying a series of probabilities together which include the number of new stars per year, those with habitable planets, the probability of life on those planets, the probability of that life achieving intelligence, the probability that those beings develop the ability to send and receive interstellar messages and the average lifetime of a technological civilisation. As pointed out, most of these factors are very difficult to estimate and the result of the equation may be no better than a wild guess however the number of stars formed per year in our galaxy is given to be between 1 and 10 per year. Some estimates given on the number of civilisations in our galaxy range from 10 for short lived ones and millions for long lived ones giving a geometric mean of 10,000 civilisations [CI: see also this interesting paper].

[CI: we haven't been able to leave the Solar System to explore possible habitable exoplanets to find closeup evidence to make more informed guesses. We would need to send out starships, interstellar probes or large space telescopes could provide some indirect evidence, however given the number of galaxies in our observable Universe and the number of stars per galaxy (in the hundreds of billions, upper guess 400 billion for the Milky Way alone) and given that astronomers are finding more and more planets around stars (ie planetary formation may be a common phenomenon around certain stars) and given that some of the base molecules required for life as we know it have been confirmed in the interstellar medium, my point of view on this is despite the fermi paradox (explained later), it is highly unlikely that the only lifeforms (intelligent or otherwise) reside only on Earth.]

An average density of civilisations in our galaxy can also be guessed and notes that they are less likely to be near the galactic core because of the shortage of heavier elements and the possible violent black hole at the center: "For galactic volume about 10^13 CLy (Cubic Lightyears), excluding core, each civilisation is surrounded by 10^9 CLy, and the average spacing is thus about 1000 Ly, or about 1/6 the thickness of our galaxy." which would be problematic for communications and any plans to meeting them in person.

[CI: Photo: A panoramic view of our galaxy with closeup towards the center. Anyone out there? (ESO)]

The author then moves on to discuss the Fermi Paradox or "the great silence" and explains the key link between other beings and interstellar travel: "Life has been possible in our galaxy for so long that some other civilisations should have been around a long time and engaging in widespread travel, if only by probe. Yet they are not known to have visited us." and hopes that this paradox is an apparent one and an explanation will eventually remove this paradox. Many reasonable and wild explanations have been put forth as to why no contact has been made so far and the author outlines many of them. Some have suggested that "absence of evidence is evidence of absence", others that habitable planets may be rare or life may not start easily on habitable planets or intelligent life might be a rare step in evolution, technical civilisations even rarer or some civilisations may not want to or are unable to venture out to other star systems or we are in a region of the galaxy where no beings have ventured or sent messages or we already have been detected and unknowing to us a fleet of starships are on their way to Earth or because of a "Codex Galactica", Earth has been quarantined by "them" and no contact allowed, or etc. etc.

Searches for evidence of other beings (SETI) are ongoing and have been mostly in the radio spectrum using large radio dishes and very sensitive receivers searching for any meaningful signals buried in the galactic noise. Some of the technology outlined was already discussed by the author in Chapter 7 and as pointed out SETI searches are difficult: "The million directions in space (or million stars) at which to point a receiving dish, the billions of one-cycle channels to be examined, the short time available to "listen", and the rapid decrease of power with distance are some of the factors making search very difficult. Power is not the main problem. Presently we have a receiver (using the Arecibo 300m dish) which could detect messages sent with a similar dish from 15,000 Ly away, and further if they use more power than Arecibo engineers have." and extensive searches of several hundread stars have been conducted at and between 1420 Mhz, 21 cm wavelength (hydrogen) and 1666 Mhz, 18cm wavelength (hydroxyl molecules) the band being referred to as "the water hole", the logic being the two combine to form water which is a necessity for life, other beings might decide to search or transmit radio signals in this band which is also relatively quiet.

It is pointed out that several intelligent signals may be reaching us right now however we may not be looking at the right directions or frequencies and furthermore: "SETI has been thought of as a cheap alternative to interstellar travel (still requiring billions of dollars and much donated effort for a semi-thorough search) [a-Finney 1985]. But SETI would be useful in finding destinations for travel, and could be a program parallel to a starship program."

What if we receive an interstellar message? According to the author this would profoundly affect the world. Principles and protocols have already been prepared for initial action on confirmation of the message. Basically scientists have agreed to cooperate in the confirmation then announce the evidence to the public fully and openly "presumably this includes all data on the content of the message even though deciphering it early is unlikely." [CI: for an interesting movie on all this see Contact]. If it comes from a star nearby, it is pointed out that a serious study of traveling there would begin and many subsequent messages planned in preparation.

So far our main SETI work has has been listening however one message has been sent intentionally from Earth in 1974 using Arecibo. The message was transmitted to the Hercules Globular Cluster M13 25,000 Ly away at an effective power of 3 TW [CI: M13 shown below with the depicted message and a relevant quote from James Jeans, see also this 35th anniversary message sent last year from Arecibo.]

Interesting point made by the author on p268: "Considering the time and cost of a full search in the radio spectrum, not to mention other possible channels and sending our own messages, interstellar travel is not necessarily slower or more costly in the long run." Further considerations are also given to search in other parts of the spectrum such as laser signals (10 KJ pulses would outshine stars). Further studies are also looking into the possibility of detecting other possible signatures left by large and advanced galactic civilisations such as excess heat for a given class of star due to a hypothetical Dyson sphere partly surrounding the star, such gradual change over time may also indicate their space engineers have been busy working on the structure.

What would happen if visitors actually came to Earth? Apart from the expected mass histeria, scientists would get real busy with almost every field of study deeply affected: "visits with the visitors would need to be leisurely to treat them kindly and respectfully, and new complex programs and procedures would be needed to allow many people fair and full access to the visitors and their knowledge." hopefully they won't be hostile beings with sinister purposes in mind and keen to exchange knowledge with us.

The author then moves on to discuss habitable planets which are defined: "(somewhat anthropocentric) as planets in the pleasantly warm biozone around a star with adequate water, breathable (to us) air, stable orbit, low eccentricity, reasonable rotation and axis tilt, absence of very violent weather and high radiation (including UV), and other factors." The interstellar medium must be relatively stable with very little instellar dust clouds passing by (which would block the precious sunlight). Also mentioned are the dangers of closeby supernovae which can increase radiation levels by 1000 to 10,000 if within 30 Ly and would be harmful for developing life. One study suggests that a supernova is expected in any spiral arm galaxy every 100 million years or so. Long term stable stars (with life spans in the billions of years) are also required which are stars of

[CI: Diagram: Theoretical habitable zones for various stellar masses.]

types F, G, K and M spectral classes which make up 90% of all stars. A, B and O type stars are more massive than our Sun and are said to change luminosity too rapidly with fast rotations and unstable habits not very good for a stable biosphere for life which requires some stability in the system over billions of years. The past ice ages here alone are said to be due to variations in the Earth's orbital distance and orientation from the Sun by only a few percent. Current theories also suggest that planetary formation from collapsing nebulae can only form around a single star however some research has suggested otherwise: "A system with two or more stars would not permit stable orbits for planets unless the stars are far apart, at least four times the distance to the best place for habitable planets."

[CI: Photo: The Orion Nebula with closeups of planetary

systems in formation around their host stars. (APOD)]

Other interesting points mentioned: "Low-mass planets do not have the gravity to hold the lightest gaseous elements hydrogen, helium, nitrogen, and oxygen, especially if they are warm. A small difference in gravity or temperature has a large effect on the time over which gas molecules can escape [recall molecular speed in Appendix B for 1.2]." and many other considerations are given as to the possiblity of habitable planetary formation. Taking account these various factors and considering planetary formation models, the author gets back to the Drake equation and mentions that the number of stars with planets could be 1/2 but the number of habitable planets per such star (not including M stars) could be less than 1/10 and some have suggested a factor of 0.001.

The origin and evolution of life is also discussed, how life begins on a planet is very important to whether intelligent life eventually develops or not. We also don't fully understand life as is on Earth and have only one biosphere to study however: "The self-regulation of the biosphere would be an important explanation of how a planet can remain habitable over long times and extend the chances for life and intelligence. Indeed, the dominant form of life on Earth, by mass and by global effect, is micro-organisms, mainly bacteria. Bacteria are a large source of oxygen. Plankton in the ocean surface remove much CO2 and release dimethyl sulfide that helps nucleate clouds (which helps reflect excess solar input)."

How life began on Earth is still uncertain in detail however it is mentioned that organic molecules may have originated from comet collisions and points out the Miller-Urey experiment which produced amino acids and other biochemicals with UV radiation in a simulated primordial Earth ocean and atmosphere [CI: some more recent studies have also indicated that early genetic code was based on a smaller number of amino acids (only those available in prebiotic nature), see this interesting paper and the Last Universal Ancestor.] Spectral analysis of the atmosphere of exoplanets using sophisticated telescopes may give an indication of life on those planets. Some molecules to look for would include oxygen, methane, ammonia, nitrous oxide, dimethyl sulfide (from Planckton as explained above), terpene vapours, chlorofluorocarbons, and other gases emitted by lifeforms would be an atmosphere not in equilibrium. NASA's exobiology program is studying the above and many other factors including the possiblity of life on Mars, Titan and other places.

The author also points out that several studies have also looked into the possiblity of whether life can develop in environments other than luke warm water: "A few other liquids besides water (e.g. ammonia, oils, silicates) might be good solvents for the complex chemistry needed for life at other temperatures from cold (-50°C) to very hot (1000°C)." however notes that no experiments have been succesful in making interesting chemistry with other base multi-bonding elements such as silicon which could provide the basis for complex "organic" structures at higher or lower temperatures. Several moons in our Solar System do have interesting compounds including liquid methane, ammonia, nitrogen, sulfur etc however no evidence of intelligent beings have been detected on them.

Even if life turns out to be spontaneous on planets with the right conditions, according to some evolutionary biologists, the development of intelligent life (the next Drake equation factor) with humanoid bodies would be very unlikely however other scientisits suggest intelligence would readily appear within a few billion years however: "More generously, at present no one can say how likely a repeat evolution of humanoid form and/or abilities is under similar conditions. Biologists are familiar with the nearly endless number of variations and branchings in evolution and the lack of ultimate purpose or design (teleology) in biological nature. Thus they are inclined to a view of uniqueness for any life form. And almost any form may appear as time goes on and the environment changes." The chance of intelligent life developing communications technology is given for the next Drake equation factor between 1/100 to 1/10 and opinions are speculative.

Several speculative theories on the spread of civilisations throughout the galaxy are also outlined and some interesting numbers for thought are given: "If a high estimate of 10,000 civilizations are actively spreading in our galaxy in an epoch of 10,000 years and typically advance 100 Ly (or 0.01 Ly/year), then the chance of encountering one in a given region is only about 0.001, rather low." A scale known as the Kardashev scale lists three types of civilisations based on energy usage: I Earth scale, II stellar scale, and III galactic scale, we are currently below Type I. The author also mentions the interesting cosmological princliple: "the Universe must be physically (therefore biologically) about the same everywhere, that nothing special occurs in one place that cannot occur elsewhere. This principle is a modern version of the Copernican view in astronomy, that Earth is not the center of everything."

Several possible case scenarios of humans visiting a habitable planet without life, with primitive life and/or with intelligent life are then outlined. If the civilisation is capable of radio or otherwise communication, contact should be made first via this avenue to agree on the timing, method and purpose of the visit instead of just dropping by. If no communication is possible for them to space then a cautious landing may be needed for first contact however as discussed in a previous chapter by the author, landing has severe technical problems attached to it notably the problem of getting back to space. One interesting point raised on p284: "Just by their presence humans would begin altering local life." If a planet is found which lacks habitability, making a suitable biosphere suited for humans may be possible over a very long time. Just as was done on Earth, bacteria could be used to make an oxygen atmosphere, remove methane and CO2 and even aid in warming or cooling it, this is known as "ecopoiesis".

[CI: Image: Terraforming of Mars one day a possibility?]

Many ethical issues would need to be considered if there are already lifeforms (intelligent or otherwise) on the planet. The chapter concludes with an interesting discussion on how humans might coexist with possible beings on their planet (hopefully peacefully) and discusses various issues including possible competition for resources, developing a human outpost on their planet while not interfering with them and even possibly continue to explore the galaxy with those beings to seek out other new life and new civilisations together.

In the next part of this book review series we'll look into the last chapter of the book where the author outlines other more speculative energy and propulsion ideas related to interstellar travel and some conclusions on the various topics discussed in the book.

Part 6: Book Review - Prospects for Interstellar Travel

2010-02-07T20:13:00.001+11:00

Continuing on with this book review series, we look at Chapter 9 where the author considers the various biological factors for the starship habitat design. A deep understanding of ecological and biochemical systems is required if one wishes to consider the case of sending a starship with 100 people operating over 30 generations for 1000 years. Discussion of the various factors that might make it difficult for humans or other biological beings to survive for these long periods are also considered however: "it is expected that if the physical problems of interstellar travel can be solved, determined humans are likely to solve the biological and social ones." The social and ethical issues for humans remaining in this closed system for these long periods are also considered.

Several systems of the closed ecosystem of the starship are outlined by the author. Heating is stated not so much as a problem as a human idles at about 100 Watts and 200 W when moderately active and gives a value of 1000 W total per person when one takes into account the typical equipment that the person will use such as lighting, computers, cooking, shop tools, lab instruments etc. Other equipment outlined for the habitat would include instruments, water pumps, ventilation system, environment recycling system, light for food growing etc. All these produce heat and for 100 persons an estimated total of 1 MW is given. Keeping temperature at say 20°C wouldn't be much of a problem because of the habitat's insulation and any excess heat can be sent to storage areas as a dump heat. Most of the lighting in use would be needed for food plants which need at least 1/10 of Earth's solar intensity or more than 100 W/m^2 with a certain spectral quality.

Atmospheric requirements for human needs requires a pressure of at least 13,000 Pascals (bit over half of standard Earth atmospheric oxygen) together with Nitrogen at 27,000 Pa which is relatively inert for humans but necesaary for some organisms. CO2 levels must be kept below 400 Pa and humidity should be kept below 20% Rel. to let people cool without sweating too much.

An estimate of this habitat volume is given at 30,000 m^3 for a volume of 300 m^3 per person. Water is vital to all organisms and a sophisticated water recycling system will be needed where: "purified water must come from waste treatment discussed later and can be of several grades: drinking and cooking; washing bodies, clothes, habitat, and equipment; watering plants; medical and laboratory; and industrial processes." Use is then mentioned of deionized water to prevent corrosion in the plumbing pipes, small amounts of minerals can be added to drinking water later for taste. Waste water will need non-corrodible pipes. Upto 100 tonnes (upto 1 tonne per person) is given as the total requirement with most of this going to watering the plants.

What would life be like for the starship inhabitants on their way to the stars? The author gives us an idea what the ecosystem needs to cope with: "People must wake, toilet, eat, wash body, clean special parts (nose, ears, hair, nails, teeth), clean living area, snack, work on familiar and new tasks, toilet, converse, make love, wash, cook and eat, rest, exercise, work, eat, meet, converse, repair clothes and other personal equipment, snack, wash hands, have fun individually or with others, toilet, and try to relax and sleep after another domestic day in a small starship hurtling through space. In zero gee all these activities would be different, with some harder, some easier... sleep and sex might be fun since one can be comfortable in any position."
[CI: For the curious, read this interesting article on sex in zero gee]

Studies have shown that for current humans if they remain for long periods of time in a zero gee environment then this will present some biological consequences which can include: "blood redistribution with blood puffing up the face, water loss, space sickness with motion and orientation problems, muscle loss, bone loss, cardiovascular deconditioning, and irregular heartbeat." Very long periods at zero gee may cause permanent changes and humans may over time adapt to a different physiology suited to the zero gee environment if artifical gee systems turn out unfeasible on starships. Current astronauts on the International Space Station regularly exercise with special threadmills to give the muscles something to push against however for a large starship complement with many people it is mentioned this may not be practical. Space medicine recommends 0.9 gee continually however humans can adjust to 0.5 gee and readjust back with treatment and rehabilitation.

Several options are outlined to creating artifical gee in a starship. There is no known propulsion method that would provide continuous linear acceleration near 1 gee. Large rotating structures are considered, notably a colony ship about 0.5 Km in radius rotating once a 1 minute will generate 0.5 gee however these rotation habitats or wheels have many technical problems apart from shielding and strength issues, the bearings at the center of the structure need to be "frictionless" using superconductors for magnetic support. Other problems can include vibrations and gyroscopic effects on the starship when altering course heading. [CI: some examples are shown below from the Mission to Mars movie.]

Photos: Examples of rotating habitats providing artifical gee for the crew (The Space Review)

Food issues are then discussed: "On a starship producing and preparing food must be very efficient and reliable so that most voyagers are free to spend most of their effort on other activities." If 8 MJ or 2000 kilocalories is taken daily, this corresponds to a minimal power input of 100 W for a human (just idling and awake). Eating animal products seems unfeasible however people can survive well on grains (which have protein), vegetable and fruit diets even without milk however "milk" and "cheese" equivalents can be made from soybeans as the Chinese have done for the last 3000 years. Issues regarding growing plants and food engineering are also discussed. According to NASA one would require 20m^2 of growing area per person however 10 m^2 could be used if using efficient plants. In order to study all this NASA and others have funded studies which have looked into all the various issues related to a closed habitat ecosystem, known as Controlled Ecological Life Support Systems (CELSS). A diagram is given on p218 showing a simplified flow chart of this ecosystem:

The waste treatment system shown in the diagram above would have to process 0.5 tonnes of sewage and food residues each day for 100 people and at least 10 tonnes of water. [CI: Current research on efficient waste recylcing systems is being undertaken by various space agencies.] Several considerations are then given to population control and reproduction over the generations onboard the starship. An interesting point raised: "If aging as a fundamental biological problem is solved, interest in interstellar travel would change."

Another option given is hibernating people for the long voyage which would eliminate the need for food production and save considerable power, and touches on issues which are related to cryonics: "Frogs are the highest animal yet to survive being frozen solid." [CI: today some people have signed up to be placed into cryonic suspension shortly after their clinical death, the alternative of burial or cremation results in certain information-theoretic death with no chance of revival in the future.] A discussion is also given on what to do with dead bodies in a starship, recycle into the ecosystem, jettison overboard or some may choose to be frozen for later burial are possible options. Some strange proposals have also been outlined sending human embryos by probe to distant planets with sophisticated robots onboard which would see them through to adulthood to start a society on a new habitable planet [CI: reminds me of the nurse robots in The Matrix movie which grow humans for other purposes]. This would reduce the starship size by not sending adult human crew however as the author points out the robotic equipment might not function for that long and supporting equipment and shuttles would still be needed but most importantly: "there is plenty of evidence that children developing without commited human parents come out lacking essential qualities. A human colony that we would recognize as such might not be the result."

[CI: Photos: Left: can understanding how bears hibernate help humans hibernate one day in their own high-tech caves? (Miller-McCune) Right: Robotic nurseries growing humans, very strange but one day possible? (Dansego)]

The author then discusses radiation (energetic particles and photons) issues and possible effects on living organisms: "At 0.01c the forward radiation has energy about 50 KeV per particle and a flux or intensity much greater than cosmic. At 0.1c forward radiation at 5 MeV per particle is very serious." Energy dumped in tissues or the ionization can disrupt fragile biological microstructures such as DNA and cause permanent damage to the retina and neural cells which don't replace themselves. In our local space the average cosmic radiation is given at 10 rem/year if it reaches living material or equivalent to about 100 simple medical x-rays. However the allowed dose for people is about 0.5 rem/year (0.005 Sievert per year). Shield systems were discussed in the previous chapter (2m solid shielding is needed from all sides the ecosystem which amounts to 5 tonnes/m^2) however several radiation dangers are outlined notably the danger of radiation from solar flares which can give doses of hundreds to thousands of rem over a few hours at the distance of Earth. 500 rems in any short time can be lethal. NASA suggested that astronauts could take about 200 rems if received over several years.

[CI: Photo: X-ray image of one of the most powerful recorded solar flares in history (APOD)]

Other more familair hazards outlined include dangers from noxious chemicals, injuries from equipment, electric shock, electric and magnetic fields, fires and other dangers. The equipment needs to be designed to be people friendly (if human crewed) that is no sharp edges or corners, hot spots, slippery handles, no toxic emissions etc. For example it is mentioned that plastics, glues and some fabrics keep low levels of solvents which are released over time, these and other harmful gases would need to be removed by the atmospheric filtration system.

Some medical considerations are outlined and notes that: "A different approach to medicine seems necessary, perhaps one based on a small set of medicines, full understanding of human genome (our 3 billion unit DNA code) and immune system, and a computer model of human physiology that can specify individual drugs to be synthesized." and mentions the possible use of a universal biochemical synthesizer and genetic engineering. There are upto a million human deseases to keep the medical staff busy and any epidemic on a starship would be a catastrophe. Good advice for anyone is given including keeping a good diet, hygiene, exercise, good sleep and safety. [CI: see also the future possibility of using nanotechnology such as nanobots (atomic-scale robots comprised of individually arranged atoms and molecules) to seek and destroy known and new planet unknown deseases at the cellular level inside the body, see below.]

Video: Nanobot destroying an unhealthy cell (Rutgers University)

The chapter concludes with several considerations given to large colony "worldlet" ships and several references are given including some from Johnson and Matloff among others. One outlined example: "A rotating cylinder colony of 1 Km radius and 10 Km length has an inner surface area of about 60 million m^2 (plus end caps), could support upto 600,000 people, and masses about 500 million tonnes shielded [b-Johnson, fuel not counted]." Propelling these massive ships would be a major problem but it is mentioned interior lighting would be even a larger problem: "The electric power needed to provide 1/10 sunlight on 60 million m^2 with broad spectrum 30% efficient lamps is about 20 GW." or equivalent to 20 nuclear power plants and this is an underestimate because food growing needs more light intensity. Some energy diversion from the main propulsion system may be possible depending on what system is used.

We now move on to Chapter 10 of the book where the author examines some of the psychological, social, philosophical, political and economical aspects of interstellar travel. The mission is again assumed to function for 1000 years and considers both human crewed and some of the benefits of robotic only missions.

Regardless of the mission duration (very slow or ultra-relativistic), consideration is given to if people would volunteer for such a dangerous mission in the first place: "if the call went out for a hundred or a thousand super-multi-skilled brilliant specialists and generalists, plenty of volunteers would appear for this ultimate trip...[however]... It is difficult to say how anyone would personally benefit after the glory of starting the great voyage wears off in years or decades and isolation sets in. " Some have suggested that 10 people for a very fast starship mission would be the bare bones minimum if the starship is "ultra-reliable" and has near automatic food production. Two of the people might need to be expert medical doctors. However the author's estimate and others give a minimum of 100 people for the skills required onboard and considers the problem of population number fluctuations in a multi-generation starship and genetic variability. One interesting point made on p236:

"The people who leave Earth will not be the ones who arrive at a different star, barring some very major improvements in human longevity, body preservation, or starship propulsion."

Many psychological issues are touched on by the author and notes that for a succesful mission people who decide to go should be doing so for positive reasons as those with negative reasons may not find what they are looking for on a starship: "People would choose to take a long journey for positive reasons such as scientific interest, need for new adventure and challenge, or deep curiosity (not all would have a scientific frame of mind)." and notes that: "People would choose to build a starship if it were at all feasible because some people (mostly men thus far) like to build large difficult, dangerous, systems which move fast and amplify and project personal power." Some further considerations are also given to the social structure in a starship and as suggested for any large technical system, a hierarchical command structure is most efficient especially when dealing with emergencies which would be too slow to be dealt with via a democratic vote by committee. Other social aspects are also discussed noting that for long term success of the mission social stability and commitment is required over several generations.

Several pages are also devoted to discussing political and economical aspects with regards to sending a starship on a long interstellar mission and notes that: "the starship should not be taking significant sums away from the ability to pay for education, health, local research, pensions, and the like." otherwise the whole enterprise would not be popular by the community at large and people have to survive here and now and also notes: "The money spent on the starship is somewhat like money spent on the military: it is spent with no immediate return." and more importantly:

"Already over 10 T$ have been spent on military armaments, enough money to build 10 space colonies or send a small interstellar probe instead. Surely a modest mission to a star would provide more inspirational, philosophical, scientific, and economic benefits to many nations than preparing for war has."

Cost estimates for a starship would depend among many other factors including the propulsion system used however the author gives some comparaisons. The Daedalus project was estimated to cost 1 T$ to 10 T$. The Apollo moon program cost 30 G$ (billion dollars) and suggests because of the million times greater Kinetic Energy that would be required for an interstellar mission, this would be an adequate cost factor estimate however something of the order of 1 T$ would be the minimum for a prototype 1 tonne probe (affordable over 10 years to a determined nation). The author also reminds us that starship construction will have to be built from materials already in space or transported from locations with shallower gravity wells such as the Moon.

In the next part of this book review series we'll look at the following chapter which deals with the possibility of extra-terrestrial life, SETI, galactic civilizations and first contact issues.

Part 5: Book Review - Prospects for Interstellar Travel

2010-02-04T22:47:00.001+11:00

Continuing on with this book review series, we look into Chapter 8 where the author discusses further some of the technical issues which apply to a starship (probe or human crewed) leaving the propulsion side of things mainly out which were already covered in earlier chapters. It's pointed out that "In accord with earlier findings on propulsion, reliable operations for a thousand years is assumed to be needed for a starship unless discussed otherwise." [CI: 1000 years! Back to Engineering Rule 6 ?]

The chapter starts off by considering starships as a closed system (it isn't strictly a closed system because of mass-energy equivalence and propulsion exhaust energy flow) and considers leakage of material and energy to the outside space. Remember that the assumption is for a very long journey so if material and energy leak past the boundary or envelope of the starship then there won't be much left over that time. Small leaks could be by small gas leaks or water vapour, erosion by dust collisions, loose atoms from the outer hull of the starship "avoid painting the starship", radioactive decay from many materials etc. In the diagram on p184, the author sums this all up and also mentions the use of a scoop to make up the loss of material and try to acquire material and fuel along the way from the interstellar medium:

The author then discusses various issues concerning deterioration and reliability of the starship: "Everything except atoms themselves deteriorates over time. In this century, unlike some earlier times, most engineering is limited to equipment lifetimes of a few decades and dependent on continual maintenance. A starship might require near-perfect performance for a thousand years. The longer the mission the more chances for failures at all system levels. Most deterioration has a systemic aspect. Something fails a little, the failure provides a route or feedback for more failure, and so on until catastrophe occurs." Several examples are given notably familiar corrosion and oxidation (inside the starship with oxygen/water vapour atmosphere for the crew), worn bearings, leaking fluids: "once a small flow starts, ions in the water attack the metal parts of the valve, eating it away and increasing the flow until the washer can no longer seal the channel that has formed." and behaviour of metals in a strong electric field.

Wherever there is rubbing of surfaces (lubricated or not), interaction of matter, flow of fluids, collision of particles with matter as in vacuum tubes (older TVs, laser tubes etc), deterioration over time occurs. It mentions that vacuum tubes last decades but working for centuries is unlikely however the use of solid state devices is recommended wherever possible.

The vacuum of space also causes some deterioration and the author points out that some atoms in materials can acquire Kinetic Energy to jump from surfaces and are forever lost in space and there's no atmospheric pressure to stop them: "Many organic solid materials (polymers or plastics) cannot be used long times in vacuum, as their solvents "evaporate", leaving them brittle or without strength. (Same solvents would make an unhealthy atmosphere inside). Most lubricants cannot be used, as most known fluids are not stable in vacuum." [CI: all this reminds me of a recent materials space exposure experiment NASA has done on the International Space Station to study all this, see below:]

Photo: Various materials exposed outside the International Space Station for one year
to determine how they behave long term in the vacuum of space (NASA)

In an attempt to engineer complex systems to be fail-safe, the author points out as discussed in Chapter 5 that systems are made with several layers or levels of self-correction. A good example given of a semi-complex system is an engine with moving parts and discusses the lubrication and cooling systems, the safeguards in place and points out that the example given is relevant because: "rotating systems are likely to be put in starships". Temperature also plays a major role in deteriorating systems such as solar sails and propulsion units because this causes misfits and stress on the various components of the system and long term deterioration, it is pointed out that temperature differences on a starship should be kept minimal wherever possible and: "The warmer a material is, the more agitated its molecules are and the more likely the weaker types of molecular bonds will randomly break." Back to the general engineering rule: the general failure rate doubles with each 10°C increase in temperature and also drives unwanted diffusion of atoms within materials. All this presents problems for example for solar sails approaching relatively close to the Sun to get a boost and a discussion is given on the reliability on semiconductor electronics with temperature. It's also pointed out that some metals and most plastics become brittle when very cold (3K) however gives a reference from which it is found that Titanium alloys, aluminium, stainless steel, copper and nickel keep their strength and toughness at these very cold temperatures, these metals are relatively cheap and easily obtainable which is good news for starship Engineers.

The question of reliability is a major field of engineering: "Reliability results from any or all of several approaches: multiple (redundant) backups, long-term testing during development to establish failure rate and mode, full understanding of the science and multiple-level engineering involved in a device, and identification of all operating conditions in which the device must operate." A discussion is also given with regards to the 1986 Space Shuttle Columbia accident and past nuclear power plant incidents. An interesting case scenario is given for a starship: "If, in a system like a starship with perhaps a million critical parts, each part has one chance in 1000 of failing in 1 year, then about 3 failures per day can be expected. A series of these can constitute catastrophe; for example, the water pump fails, then the power for the shop that fixes pumps fails, then a leak develops in the hull requiring the attention of the same people trained to repair the preceding." and gives another example to bring the point that: "several failures can occur in a short time which are independant initially but afterwards are interactive, making catastrophe out of smaller crises. A longer chain of failures could destroy the starship as a viable system." The Apollo moon program is mentioned to have attempted and achieved failure rates of 1 in 10,000 for all parts for a 10 day mission while the Daedalus study with 100,000 parts required an overall failure rate of 1 in 10,000 over 50 years.

With the possible loss of material from the ship over time, several options are outlined how to recover the material back and discusses the importance of recycling and repairability / maintainability issues including the possible use of maintenance robots and their pros and cons compared to human crew. [CI: The Daedalus study has "Wardens" or mobile maintenance robots able to undertake various tasks on the ship during the voyage.]

Image: Adapted image showing one of the Wardens of Daedalus (This is Rocket Science)

A good deal is covered on the dangers of radiation to the ship and crew, this refers to charged and uncharged high speed particles, energetic photons from material hitting the starship at high speed, interstellar particles and photons, particles from any particle or nuclear drive and solar flares: "At 0.3c, protons carry about 50 MeV and are very dangerous; at 0.1c, 5 MeV and still bad; at 0.01c, 50 KeV and easily shielded. At 0.1c, interstellar protons are encountered at the rate of at least 3*10^12 particles/m^2, bringing energy at a flux (or intensity) of about 10^13 MeV/m^2 or about 1 J/m^2s. The intensity of radiation is approximately proportional to starship speed cubed." It is noted that a shield of a given thickness doesn't absorb all the radiation but as the thickness increases, the amount that gets through exponentially decreases. Radiation from "cosmic rays" in the form mainly of energetic protons and other heavier particles can be a problem as they can range from 10 MeV or lower to 10 GeV or more and can come from any direction but notes that: "radiation from starship motion is much more serious than cosmic background by a factor of about a billion at 0.1c and still a million times worse at 0.01c."

It's also pointed out that radiation from the propulsion can also be a serious problem, in the case of the anti-matter drive, this can put out dangerous 200 MeV gamma rays in all directions for eg. Radiation from a fusion drive might be mainly 14 MeV neutrons depending on the fuel used and would need a 1 m thick shield, for cosmic particles, 2 m of dense material would be required to stop them below 10 GeV. For the Daedalus above, the shield used is made of 50 tonnes of Beryllium only 2 cm thick mainly for dust erosion however 10 MeV protons are expected to be stopped 1 mm into shield at an erosion rate of 1 tonne per year. However this shield isn't thick enough to stop some of the more energetic cosmic radiation. Radiation shielding is important because computers and electronics, data storage devices, sensors etc are sensitive to all this and not to mention the crew. It is also noted that "the Voyager spacecraft were designed to work at the level of 150 kilorads per year (about 1 million rems, depending on the particles), as encountered near the orbit of Io around Jupiter, and did not suffer significant electronic failures" and these days more progress as been made with more durable electronics.

Several active shield systems using electric, magnetic or plasma are then described which could deflect ionized interstellar gas (not neutral gas) and cosmic rays, one system described: "If protons and other nuclei upto 10 GeV in cosmic rays (which inevitably are ions) are the primary radiation problem, then a potential of negative 10 billion volt (10 GV) would be needed to repel those protons." Another option outlined is to try to imitate the Earth's dipole magnetic field (which protects us Earthlings) by creating one around the whole starship using superconductor coils carrying a billion amps. This would deflect some particles and collect others at the "poles". One concern pointed out though is how much of this strong field would penetrate the habitat volume and ship design would have to take this into account. Dust and neutral gas cannot be deflected by fields but a: "foil sail ahead would ionize both as they pass through, so that fields could prevent erosion." Another shield system described also good for larger size dust grains or even small rocks was studied for Daedalus and involved using a "shield cloud" of dust that would be placed ahead of the ship to vaporize these larger objects. 10 Kg of fine dust would be used to create a cloud 100 m in diameter several hundred kilometers ahead of the ship. The dust packet would have its own propulsion system for delivery to the target and this would convert any object less than 0.5 tonne to plasma. Anything larger than small rocks such as comets need to be avoided.

Image: Earth's magnetosphere shields us from the harmful charged particles

from the Sun, good idea for part of a starship's active shield system? (Wikipedia)

In the next several pages, the author discusses various issues regarding computers and long term data storage for use onboard starships. These can handle large numerical calculations associated with ongoing operations and model complex systems. An example is given in the case for navigation on the way out of the Solar System where the computer can predict the effects of non-spherically symmetric gravitating bodies on the starship, effects of dust, solar wind, photon pressure and fluctuations in the drive itself. Reliability and self-diagnosis is emphasised together with backup systems. Self-reproducing systems might be a long way off but mentions that a mathematical theorem has been proved on paper that systems could be organized to reproduce [b-von Neumann; b-Dyson] and that "This abstract work is not purely speculative because biological systems using information coded in DNA follow a similar process. Indeed, the minimum number of coding elements (base pairs) needed by a virus that has its own reproduction machinery is about 200,000." If a system can reproduce itself, it could also fix itself. There would have to be two computers working together so one can turn off/on the other computer to be fixed while it replaces or fixes its parts.

Also mentioned is the use of Artificial Intelligence (AI) especially for interstellar probes on their own: "Probes without human guidance must be adaptable and make good decisions from vague information, even evolve to improve themselves. This capability is widely proposed as necessary for long-term missions that must do new things at new planets, even "talk" with new civilizations encountered, decide what to tell "them", and determine whether they are any danger to us." I like the last sentence of this paragraph: "There are limits to what we can do with logic systems (real computers or software) but no limits to the variety of situations in the Universe that those systems must cope with."

Data storage issues is then discussed and according to the author we would need to load the starship with at least the amount of information found at a major university library or 10 Terabytes plus a wide sample of Earth arts and other material. Various storage media are compared comparing their long term reliability however the last part was particularly interesting: "If a cubic millimeter (about 10 million atoms thick) is used for information storage with each layer of atoms laid down as one kind or another to encode information, it can store 10 million bits. A cubic meter (mass about 3 tonnes) could store on this basis 10^16 bits or 100 times the above requirement. If information could be stored and retrieved atom by atom in the cubic millimeter, it could hold about 10^21 binary bits, enough to satisfy thousands of high-tech civilisations. These are the nearly ultimate limits of information storage."

Possible breakdowns are discussed and points out that at least three or more large power sources should be available at all times onboard the ship, some backup options given include hydrogen/oxygen fuel cells and Radioisotope Thermoelectric Generators. Other ideas have been suggested for emergency power, one of them is the use of a 1 Km coil in the weak interstellar field which would only produce 10 V per turn at 0.1c via magnetic induction.

The chapter concludes with a discussion on transportation issues between a fleet of starships (send several ships instead of only one makes sense safety wise but costs more) and transportation between the starship and moons or planets. Radiation can be a serious problem to the shuttles travelling between the starships at high speeds as pointed out earlier and storage, fuel, maintenance, protection from erosion are also issues that will need to be addressed. Shuttle transport between the starship and the planet is a BIG problem: "Solutions for transport between starship and an Earth-size planet elsewhere can only be speculative." because using chemical fuel rockets to depart larger size planets is out of the question and there are no launch pads with extensive shuttle facilities on the ground at the new destination and unlikely to have nice long flat hard surfaces for the shuttle to glide and land on. The crew also need to get back to the ship even if they landed on the surface. Other ideas suggested include using extremely high strength long cables to lift items from the ground from orbit (space elevator) which maybe feasible depending if the cable made of high strength carbon nanotubes can be yarned into a large and (very long!) cable with similar strength. Other ideas mentioned include using a laser-heated rocket which requires a very large ground based laser with power supply and isn't feasible and an electromagnetic launcher has limited capability. [CI: this problem also demands Engineering Rule 6]

In the next part of this book review series we'll look into the next two chapters of the book namely more biological issues in a starship and personal, social and political considerations related to interstellar travel.

Part 4: Book Review - Prospects for Interstellar Travel

2010-02-03T17:14:00.002+11:00

We move on to Chapter 7 of the book which I found particularly very interesting. There doesn't seem to be much written concerning Interstellar Navigation and the various position fixing methods interstellar voyagers could use (the author names this as "astrogation") so let's have a close look.

An explanation is given on the basics of the celestial sphere and how conventional star map coordinates are setup from our Earth based vantage. It is natural to use angular positions of stars (ie Right Ascension and Declination) however for navigation purposes in interstellar space we may need a rectilinear coordinate system. It is noted that no standard 3D coordinate system in meter or Ly has been established for star listing positions because astronomers haven't planned on interstellar travel but this isn't a problem because spherical coordinates can be easily converted to x,y,z rectilinear sun centered coordinates [CI: for those curious read Spherical Astronomy]. This also applies to the starship's "celestial sphere" when the navigator measures star angular positions and needs to convert these to rectilinear x,y,z coordinates for a position fix on the chart. Moving to the case of the starship in interstellar space: "No absolute reference or coordinate system exists for starship travel or anything else, with the partial exception of the uniform (to 1 part per million or better) background microwave radiation.", in other words we can use any coordinate system we like, Earth centered, Sun centered, Galactic coordinates or other (such as pulsar grids) however as the author points out it makes sense to use a Sun centered system because our Sun is moving 22 Km/s (that's Kilometers per second) in a specific direction compared to the other stars and gas and the travelling ship will somehwat share this motion.

Image: Our galaxy with Sun centered galactic coordinates. (Caltech)

Typical motion of other stars is given at 10 Km/s relative to us or a 0.003 Ly shift in 100 years so we cannot assume they are fixed with respect to the Sun. To give us a perspective on things, it is mentioned that the Sun along with local stars orbit around our galaxy's center at approximately 300 Km/s and our galaxy is also moving about [CI: at 552 Km/s relative to the photons of the background microwave radiation towards the Great Attractor]. Back to our little corner of our galaxy, as the author explains, these previous motions don't affect local interstellar navigation for the starship and we don't have to measure these [CI: however measuring these would be necessary for intergalactic travel, one does wonder sometimes if out of all those 100 billion or so galaxies in our part of the observable universe if there are any beings travelling between these galaxies, will humans one day be able to venture to the Andromeda Galaxy for eg? highly unlikely]. Some further issues outlined include the accuracy of star positions as seen in the sky and their stellar distances. These should be updated wherever possible using probes for interstellar scout missions and send over the data back to Earth as distances to most cataloged stars are unknown or rough figures. Star positions must have an accuracy of at least 0.0001 Ly before a probe or starship is sent on a major mission. The starship "can update its map with new observations, calculate new star positions according to their known motions, update those motions, calculate starship motion in real time (proper and Earth), and use relativistic mathematics for greatest accuracy." Most of these tasks are ideally suited for a navigational computer linked to telescopes/spectrometers and sensors throughout the ship coupled with a 3D virtual star map showing to the crew position, heading and other navigational data. An interesting point made here is: "The first big starship should not be required to acquire accurate information along the way as it may find too late that a major course correction is needed. Course corrections of the order of 1 part in 10,000 can be made as the starship proceeds, but larger corrections are costly at high speed."

It is also noted that as far as getting lost, human voyagers would be able to monitor starship progress and recheck the position of the Sun and destination however for a probe that depends on computers and sensors: "any probe which has an error in orientation due to malfunction of steering jets or gyro, or another failure, must acquire data on bright stars and sort out which ones are to be used for guidance before correcting its orientation. Probes must use an assortment of stars for fixes and might need to measure brightnesses and spectra and compare with prepared desciptions to identify them. Getting lost is unlikely for human missions closer than 100 Ly but always a serious problem for probes."

The faster the starship is travelling, the more pronounced is starlight aberration (apparent position change of the stars due to the finite speed of light c). This must be calculated from the speed of the starship or if the aberration is known, the speed of the starship can be calculated: "At 0.1c aberration causes an apparent shift forward of stars by about 6° for those located to the sides, and less for stars toward front and rear. The apparent brightness is affected by high speed. At 0.1c intensity is increased about 20% front and decreased by 20% behind". [CI: Checkout What would a relativistic interstellar traveller see?]

Image: our view of the stars changes the faster we go due to relativistic effects which will need to be calculated, apart from the position shifts of the stars, note the brightness changes (Physics FAQ)

The author moves on to discuss starship speed measurements which can be made by doppler shift in the spectral lines from any stars or even better using the doppler shifts for known pulsars which send highly regular (millisecond to second range) radio pulses unique to each pulsar and have been accurately measured by radio astronomers (to 6 digit accuracy or better). A pair of radio telescopes on a starship could also be used for position fixing. [CI: Recent studies for a GPS-like position fixing method for use in our solar system and beyond using X-ray pulsars for even greater accuracy is ongoing]. Other navigational instruments mentioned include inertial guidance devices and sophisticated 3-axes gyroscopes using ring lasers: "if accurate measures of acceleration are fed to a computer from the gyro in all three dimensions, it can calculate from prior information on position and velocity the present location without needing outside measurements (relativistic also)." and of course the obligatory atomic clock with an accuracy of 1 part in a trillion or better. [CI: a three axis magnetometer would also be handy for interstellar magnetic field measurements but also could be used for orientation of the starship as a backup system to using stars or pulsars if the magnetic fields are well charted in the space that's navigated ie a sophisticated ship's compass. Checkout this paper: The Orientation of the Local Interstellar Magnetic Field although magnetic deviations onboard the starship may be quite large because of the high energy devices that would be found onboard.]

Another important point mentioned by the author is on the assumption: "that the propulsion force is applied in the desired direction of travel. If force direction differs from the intended direction by a small amount, an increasing error in direction occurs. For example, misalignment by 1" arc results in 100 million Km error after 10 Ly." and goes on to mention that fusion exhaust or photon reflection with large energies aren't perfectly aligned systems just like chemical rockets where the ejected material isn't exactly centered on axis which results in off axis propulsion and these are corrected for by the guidance system or in the case of the starship, telescopes locked on the structure which can detect any changes in direction from a set of star positions. "The average long-term error in direction can be corrected, but the short-term fluctuations should only be measured, not corrected". [CI: similar to the autopilot on boats, everytime the boat goes through a wave, if the autopilot moved the rudder, the steering ram would be working overtime unnecessarily so there's a "wait and see" delay setting.]

Moving on from navigation issues, the author looks at starship manoeuvers that may be required to dodge large micrometer size dust particles along the way for eg and significant changes in course headings will require substantial propulsion energy: "A 6 degrees change requires about 10% additional speed (and about 20% more energy). No way is known to recover momentum from one direction and apply it to another." and points out that changing direction isn't just a matter of rotating the starship by a small angle as it would still continue in the same direction as before until the main drive is used substantially. For minor course corrections mention is made of an inertial wheel and possibly of chemical steering jets. As it was pointed out in Chapter 4, the possible use of interstellar magnetic fields to change course has been discussed using the Lorentz force: "For a radius of turn of 1 Ly at 0.03c, slower than earlier examples yet still very fast, a 1000 tonne starship must use 1 million coulombs." with the mentioned wire requiring to be over 1 million Km long, this whole approach doesn't seem feasible compared to carrying more propulsion onboard.

The author then looks at active detection methods for detecting what's ahead in the first place. We need this information early to give enough time for the ship to alter its course. Just like radar systems, the system would transmit signals ahead and wait for reflected pulses to deduce distance, direction and size of the object however it's pointed out that the best detection is done by observing information coming from distant objects as there is no waiting time however cold dark matter emits only very small amounts of radiation not enough to be easily detectable. Some gases do not emit radio or light waves even if UV light strikes their atoms or molecules and radar cannot make matter respond, it only relflects or scatters.

Fortunetly lasers here come in handy: "Energetic laser light, x-rays, electrons, and neutrons can cause response from distant material to help identify it and determine its composition, density, speed, and temperature." however getting enough intensity for x-rays, electrons and neutrons is much more difficult compared to radio, radar and light. In order to detect sizes ranging from large dust particles to large rocks, radio waves with a wavelength of around 1mm is best and if we use two or more transmitting antennas we get better resolution, for 1Km separation we would get a beam size of 1" arc. The author points out that we still have the problem of dust erosion of the small antennas and these are even more difficult to protect compared to a single 100m dish. Another system example is given: "a system with 1 Km effective aperture can detect objects smaller than 1 mm and locate to an accuracy of 10 m in 10,000 Km. At 10,000 Km/s, there would be a 1 second warning to shift the direction of travel to miss an object. Two gees sideways would be required to shift 10 m in this time, but this amount of drive is probably not available". One option offered as an early warning system is the use of a probe which is travelling far ahead of the starship pushed by an ion drive and powered by the ship via a long cable. Once detected though, the feasible option given by the author is to demolish it by "zapping it" with a high-power laser. There is time for the laser system to confirm the target before main zap, if the starship motion is nonrelativistic. "At relativistic speeds there may not be time for detection and response to objects ahead". [CI: for relativistic speeds, it's not suggested by the author but use of an expendable detachable shield far ahead of the ship may be an option to "clean the way ahead" for the ship (still keeping its main erosion shield on the ship). Let the expendable shield take the damage rather than the vital ship itself]

It's pointed out that lasers would be very useful in detection and possibly zapping objects ahead. An infrared laser is better at detecting finer dust than millimeter radar can due to Rayleigh scattering and because of the typical sizes of dust grains the best wavelength is infrared, larger wavelengths tend to diffract around these objects. The laser light also needs to arrive at the object with enough intensity to excite the atoms in the object for a detectable energy signature for spectrographic analysis.

Image: Porous chondrite interplanetary dust particle, running into one of these at relativistic speeds will cause erosion or some damage to the starship (Institut für Planetologie and University of Washington).

The following paragraph deals with passive observations and makes the case that apart from the need to make accurate observations for interstellar navigation, interstellar and planetary studies, the sensitive scientific instruments mentioned in the previous chapter would also be useful for searching for any signs of Extra-Terrestrial (ET) Intelligence (SETI) however as pointed out: "Observation enroute will be difficult at high speeds because of interference from impinging interstellar hydrogen and dust. Most data must be collected from behind the front shielding." Several frequencies are outlined for observations in the radio spectrum and points out that at a frequency of 10 GHz, the natural noise is the lowest. Bandwidth used (the range of frequency used for one signal) is also important. The narrower the bandwitdth of the signal, the more it stands out from the background noise and the further it can be detected. We can achieve 1 Hz bandwidth or better and so could the ETs. However if broadband receivers are used, the signal could get lost if it doesn't have enough resolution in the spectrum. "Noise in deep space is due to synchroton radiation from electrons all over the galaxy at low frequencies, to background radiation at intermediate radio frequencies, and to quantum noise at high frequencies." and anything warmer than 3 Kelvin emits more radiation than the background. Hyrdrogen atoms emit radiation at 1420 Mhz (21cm) weakly and the author points out that it was first thought that ETs would choose this frequency to broadcast as it is also relatively queit. Extensive searches for unnatural signals haven't been found. Signal leakage from ET civilisations from ordinary activities is more difficult because the fequencies may be in a noisier band: "It has been estimated that if another civilization leaked TV carrier (1 MW typical, 0.1 Hz bandwidth) and radar pulses like ours does, then our astronomers could detect their leakage at about 30 Ly with our largest radio dish, 300 meters at Arecibo, Puerto Rico. Starship radio dishes limited to 100 m diameter might be able to find similar radio leakage from civilizations just a few lightyears away, a marginal capability."

Photo: Arecibo Observatory (NAIC)

The possibility of ETs using laser pulses to send signals is also mentioned and studies have shown that these can be picked out of the starlight if they are distinct from the background light. Further considerations are then given on to communications between the starship and base: "A transmitter with a 100 m dish must put out about 4000 W per cycle of bandwidth at 30 cm to be barely detected 10 Ly away in a 1 m^2 receiver. Only about 0.5 W of transmission in a 1 Hz channel is needed for threshold detection in a receiver at the focus of a 100 m dish across 10 Ly!". For the Daedalus project, the study specified a 2.6 MW transmitter for data transmission at 1 Megabit per second at 2 or 3 Ghz from 6 Ly with a 40 m dish. A 100 m dish is quite large for a starship and we have the dust damage issue to contend with, the Daedalus plan was to use the dead fusion chamber as the main dish to get around this problem. Some studies have also looked into using lasers for optical communications as well.

I'll leave out Chapter 8 "Technological Requirements and Hazards" for the next part of this book review as we have covered quite a lot of material in this part alone.

Captain InterStellar's Big Day Out: walk to the lighthouses

2010-02-02T20:28:00.000+11:00

With the busy season here on Sydney Harbour finished, I'm getting more days off to relax or spend more time with my other Physics and Compass Adjuster studies. Went for a big walk today at South Head (the southern side of the entrance to Sydney Harbour), gave my new DSLR camera a workout and did some peaceful study with the ocean for inspiration and a nice cool sea breeze :-) Caught the ferry from Circular Quay to Watsons Bay and first headed off to checkout Macquarie Lighthouse. This is the first lighthouse you'll see approaching Sydney from sea with the light at 105m above sea level and also is the brightest. The other one I checked out was Hornby Lighthouse at South Head with its nice red stripe colour scheme:

The walk along the cliffs is spectacular and you'll see many remains of the fortifications that were placed with heavy artillery for defense. The canons where no longer needed when the missile era came to age. At the Gap, the only remains of the famous shipwreck of the Dunbar was the recovered admiralty anchor:

As I was contemplating the ocean, a quote from Darwin came to mind:

Part 3: Book Review - Prospects for Interstellar Travel

2010-02-01T22:10:00.006+11:00

Continuing with this book review we move onto the fifth chapter where the author gives a rundown on the various subsystems that a starship could have. It is not about designing a starship but "recognising it as a complex system" with or without people onboard. Placing propulsion temporarily aside the chapter assumes that the ship has 0.01 to 0.1c speed capability and that the human social system is in place to support mission design, construction and long term operation.

Section 5.1: Engineering rules, was a gem: "A number of empirical rules for designing complex systems have emerged from centuries of practice with simpler systems.", this list has sound advice for Engineers working on any complex project:

Engineering Rules

Rule 0: Engineering is setting and making systems that work.
Rule 1: If there is a way for a system to fail, it will happen (Murphy's law). Failure analysis can never be complete, either. For example, some nuclear reactor accidents have involved a chain of 4 improbable failures.
Rule 1a: Design fail-safe. That is, if something fails, try to prevent anything else going down with it, or possibly arrange for a beneficial failure or a self-fixing one.
Rule 2: Humans, at least, tend to build whole from parts. Since a whole system cannot be deduced entirely from its parts, induction is part of the design process.
Rule 2a: The whole can be greater than the parts. That is, the function of the whole system can be qualitatively, not just quantitativly, different from the functions of its parts. (Note latter comments on systems.
Rule 3: Define a problem such as propulsion as broadly as possible. Even more broadly, ask: What is the purpose of interstellar travel? Identify unnecessary assumptions and biases which limit the problem artificially and prevent many kinds of solutions. Do not assume the solution (e.g. a rocket), find it. Avoid vested interest until the final design is very clear.
Rule 4: Once primary and subsidiary problems are well-defined in detail, the solutions may be half accomplished.
Rule 5: Keep everything as simple as possible.
Rule 6: Know the limits set by known science. Engineering cannot exceed known science but must wait (and ask for) further science. This does not mean that engineering cannot find new solutions to problems. The realm of engineering creativity, a result of intelligence working against entropy, is probably far larger than the realm of scientific models and laws.
Rule 6a: Be conservative with technology. This contradicts the wide-eyed technical ideas in most interstellar studies, but this rule is for using established technology at the working hardware stage, not the exploratory stage.
Rule 6b: Work from the known to the unknown. Start with experience, but take early risks to expand that experience.
Rule 6c: Models do not scale up linearly (e.g. strength-mass ratio, fluid flows).
Rule 7: Watch out for interactions. Every functioning part can foul up other needed functions by many parts.
Rule 8: Most systems involve the need to optimize conflicting functions, and trade-offs are needed where each function is less than ideal.
Rule 9: If a system of mass m needs parts, each of which masses 0.1m (or even 1m as often occurs in propulsion), stop and redesign until each part does not call for more total mass than intended.
Rule 9a: If other considerations are equal, the masses of parts of a system (and some other characteristics) might be equal in an optimum design. This rule derives from impedance matching.
Rule 10: A practical system must be reliable (to an extreme and well-defined degree for interstellar travel), operable (reliably controllable), and repairable (or better, easily maintained so breakdown is unlikely).
Rule 11: Use multiple backups for subsystems (3 or 4 for interstellar travel). Each backup must be designed as a main system, not an inferior secondary version. Use a different proven method for each system rather than achieve redundancy by making the same system three times. Hint: use several different propulsion methods. (The Voyager probes did not have backups for many components because Voyager was expected to function less than 50 years. Some of the few backups did need to be used.)
Rule 11a: Where substantial failure rate is unavoidable, use tens or hundreds of identical copies of a subsystem in parallel. (Big example: why rely on one huge tricky drive when banks of identical small independant ones are better. If a few fail, 90% of drive capability should remain.)
Rule 11b: In counterpoint to multiple backups is multiple use of the same system to save mass. This is gambling. (It is better to have 3 sails, each of which can also be an antenna.)
Rule 12: Temperature is a major confounding factor. Beyond "room" temperature (20°C) the failure rate generally doubles with each 10°C increase in temperature, the old Arrhenius rule. The size of materials changes at different rates with temperature, causing misfits and stress.
Rule 13: Systems are rarely self-stabilizing and usually have numerous ways to destabilize themselves. Know the system so well that stability can be made inherent.
Rule 14: Use self-repairing subsystems and hope that this repairs the whole system. (This rule spins off from the space age).
Rule 15: Use monitoring sensors more reliable than system components, else they are worse than worthless, they mislead during breakdowns. (This rule spins off the nuclear age.)
Rule 16: Avoid designs by committee and layers of bureaucratic review. Find the top experts who will live for the project, give them unlimited support, and leave them alone.
Rule 17: Use the same parts in as many different places as possible. (Reduce the number of different parts needed.)
Rule 18 (especially for starships): No repair services are available enroute, and no radio or rescue help after leaving the Solar System.

[CI: I'd like to comment on Rule 6 because this is highly relevant to our current state of affairs regarding our current known science and what this allows for our prospects for interstellar travel. My view on this is that the prospects are not very good with known physics. Despite all the great ideas put forth, current known physics does not allow practical interstellar travel within reasonable earth timeframes. Our known physics doesn't prevent us to venture to the stars but it makes the prospect a considerably difficult and slow undertaking and if there is no new enabling physics, this will not change even if we have a vast space infrastructure centuries from now. This is a problem because our long term viability as a somewhat successful and prosperous civilisation is directly linked to our capability of interstellar travel to colonise other earth like planets in other star systems (for breeding room and safety against extinction: don't have your eggs all in one basket ie Earth). The important question is: does Nature allow for a more practical approach to interstellar travel? Is there hidden physics that would allow this? One needs to ask for more science and question everything. Understanding the physics of the vacuum could be one step forward to answer these questions.]

A general discussion is given on possible starship subsystems subdivided into the big heavy duty systems (structure, propulsion system, powerplant, shield system, ecosystem, electic power supply etc), fine subsystems (sensors, communications, computers, science instruments etc), subsystems for human needs (storage tanks, water, food, atmosphere processing, artificial gee system, work, private and leisure areas, waste processing systems etc) and extra equipment (landing craft etc). Starship size is dependent on a number of factors however how many people it carries is one of them: "One hundred people need at least 300m^2 per person (100m^2 with 3m overhead) in the closed ecosystem habitat for enough room to enjoy being with each for decades or centuries." The author emphasises the importance of the shield which inhibits the need to look ahead: "Ineed at higher speeds, the hail of radiation would prohibit anyone or most instruments from peering around the shield to look ahead. At 0.1c hydrogen gas arrives like 5 MeV radiation."

Another good point mentioned is the importance of redundancy built into the ship systems ie have backup systems to the backup systems and the possiblity of having maintenance robots onboard for maintenance tasks of the various systems together with maintenance and power facilities for the robots themselves [CI: sounds like a good job for R2-D2? ;-)].

The sixth chapter deals with possible mission scenarios, where we might go, who and what we might send over. The author runs through our stellar neighborhood outlining the characteristics of various close stars, their spectral classes, planet formation theory and the possiblity of exoplanets in their habitable zones. Since the author wrote the book, 429 exoplanets have been confirmed by astronomers (as of January 2010), most being gas giants Jupiter-like planets) and the next several years could look promising finding more exoplanets with masses down similar to Earth. Finding an earth-like planet would be a major find for us and this would set the star system as a serious possible candidate as a destination for an interstellar journey with a precursor probe followed by a crewed starship if viable. An Earth-size planet at say 10 Ly would have an angular size about 10^-5 arc seconds requiring multiple large telescopes tied in together as an interferometer array possibly on the Moon for effective observation. Hopefully this earth-like planet will be within 10 Ly from us and not too distant. The author on p146 gives a 3D perspective star map of the forty closest stars within 16 Ly. These days there are freely available excellent 3D interactive star maps such as the flash based Exosolar (screenshot below) or try Celestia.

Image: Screenshot from Exosolar showing some of our nearby stars

Stars just like planets are also in motion, these move around in our galaxy and their stellar motion can also be observed, p147: "For almost any mission, stars move fast enough that accurate astrogation [CI: Interstellar Navigation] requires knowing and accounting for their motion. As mentioned earlier, the present Voyager and Pioneer missions will first pass some stars that will have approached closer to the Solar System at that time [a-Cesarone]. However no stars are moving so fast as to provide special close (less than 1 Ly) interstellar mission opportunity in the next hundred thousand years. Humans must wait about 815,000 years for star DM+61 366, type K and now at 33 Ly, to pass about 0.3 Ly from the Solar System."

In the scientific opportunities section, the author gives a rundown on what kind of science would be done on an interstellar mission which could include observations of stars and their planets, composition of the interstellar medium, measurements of fields and high energy particles and accurate measurements for stellar cartography. Close observation of more interesting objects such as white and brown dwarfs, neutron stars, star forming clouds, pulsars and black holes will probably be out of our capabilities as the known ones are too far away. The Crab Nebula for eg, a supernova remnant, is 6500 Ly away (not wise to get too close though because of the excessive X-ray and Gamma ray radiation levels from the pulsar):

Photo: The Crab Nebula 6500 Ly away (Hubble Space Telescope)

A general discussion is then given on several mission scenarios including those with crew onboard, simple, advanced and self replicating probes and large colony ships and outlines the benefits and disadvantages in each case. The most likely scenario that will happen as the author points out is that before a human expedition, one or more high speed probes will be sent over to the star for science data return and propulsion proof of concept. Following this preliminary scout mission, the importance of sending over people is emphasised on p152: "Once a propulsion method is shown workable locally, there will be interest in a human expedition however risky. Humans carry the ability to monitor a starship carefully, process and study much relevant science along the way, repair many kinds of failures, overcome many kinds of emergencies, and generally may justify the expense of sending them to obtain a successful mission." If viable, the case of large colony ships is discussed however "Interstellar travel will not be able to reduce population pressure because of the cost of travel" but they would be useful for small population transport for new-earth colonisation purposes. For all these mission scenarios, propulsion will be one of the biggest factors for a go or no-go decision.

In Part 4 of this book review we'll look at Chapters 7&8 which touch on Interstellar Navigation, Observation and Communication methods followed by further discussion on starship technological requirements and hazards.

Part 2: Book Review - Prospects for Interstellar Travel

2010-01-30T15:24:00.008+11:00

Continuing on with this book review, we move on to the third chapter which gives an introduction to relativity and what effects this causes to interstellar travellers when one travels at speeds greater than 0.2c (0.2 times the speed of light) this is when one starts to notice relativity effects, the faster one goes from here on, the more pronounced the effects. For different observers mass, length and time differ and another consequence is that it becomes more and more difficult for objects with mass to approach c. At 0.2c the mass of a starship for eg is increased by about 2%, and at 0.9c the increase is a factor of about 2.3. This factor which describes the mass increase is called "gamma" which appears throughout relativity:
\[\ {\gamma &= \frac{1}{\sqrt{1-\frac{v^2}{c^2}}}}\]
Where v is the velocity of the object. Particles at accelerators are routinely accelerated to 0.99c but never at c or beyond. Time dilation is well confirmed and is related to gamma. The particle accelerators in use today would not work if these effects aren't taken into account for eg. [CI: length contraction in practice will probably be unobservable for a long time]. On p75 for eg it mentions "A journey occuring at 0.866c (gamma of 2) results in the flow of time at half rate during the journey. A twin on Earth might have aged 60 years while the voyager aged 30 years.", the famous "twin paradox" which isn't a paradox as the author explains. Hint: it is the starship that accelerates, the Earthlings go about their usual business. One consequence of relativity for interstellar travellers voyaging at high gammas is somewhat troubling, p77:

"Once the regime of large gamma is entered, their Earth is gone forever. There is no way to return to their decade or their century."

In other words fast starships voyaging to distant parts of the galaxy may not return to an Earth they once knew. Assuming interstellar travel at high gammas turns out to be feasible in practice this can be a problem depending on the purpose of the mission. A rundown is also given on how relativity affects the rocket equation and relativistic energy and momentum. The last paragraph of this chapter is worth quoting here:

"Relativity makes energy a serious problem through the limits imposed to prevent speeds greater than light. Relativity also offers tantalizing solutions: the slowing of time and Total Conversion of mass to energy. How closely propulsion might approach TC is explored in Chapter 4. One could hope to find a way to travel without the action-reaction rocket method--no exhaust, no acceleration, little travel time, no deadly beams, no titanic low-mass energy source--but these are still mostly dreams from sf. Thus far it is not surprising that "visitors" from other stars have not appeared recently nor left their garbage laying about. They also must contend with what their Einsteins discover about interstellar travel. If visitors were to arrive, one of the first facts we would want to know is "how did they do it?"."

[CI: This paragraph somewhat deals with the 3 goals of the Breakthrough Propulsion Physics Project and touches on SETI issues as well. Quick BPP recap:

1. Mass: Discover new propulsion methods that eliminate (or dramatically reduce) the need for propellant.

2. Speed: Discover how to circumvent existing limits (light-speed) to dramatically reduce transit times.

3. Energy: Discover new energy methods to power these propulsion devices.]

Following relativity, the author takes us through several drives that would allow one to travel at relativistic speeds greater than 0.2c. This in turn brings in new problems such as possible hazards encountered by the ship at these high speeds.

Earlier the solar sail case was mentioned with the benefit of using sunlight to accelerate the starship while close to the Sun or star. However if the sunlight can be collected and focused by a giant focusing mirror then this could be beamed towards the sail ship over a longer period of time, this is the concept of beamed power propulsion. Not only could sunlight be beamed over but also light from a powerful laser or maser (microwaves), all this circumvents the low photon intensity past Jupiter's orbit. However not only is this system big (to provide a useful beam at a distance of 1 Ly, the mirror and starship sails described are 100km in diameter) there is the problem of stopping the starship at the destination however this wouldn't be a problem is this was for a fast flyby probe mission. Another option described is the photon drive: generate your own photons to accelerate the ship however this is shown to be highly inefficient.

Enter the anti-matter drive: "This drive determines the prospects for interstellar travel for the future as best known science can predict". Compared to fusion drives, anti-matter produces particles with much higher speeds, the author gives a table describing the outcome particles after the annihilation process if we bring together hydrogen and anti-hydrogen. [CI: In the recent Avatar movie the ISV Venture Star has a hybrid anti-matter / beamed power sail drive and a fusion powerplant, the movie people consulted some knowlegeable people in the field for a realistic starship design for the movie plot, note the red hot glowing radiators for excess heat dissipation after the decceleration phase].

Photo: The InterStellar Vehicle Venture Star from the recent Avatar movie.

In the mixed bag of high energy particles we also obtain after the reaction lots of high energy photons (highly penetrating gamma rays) and this is a problem because there are no known ways to deflect them towards the exhaust in one direction so heavy shielding is required for critical areas of the ship such as crew areas. Another problem with anti-matter is that this form of matter is almost never found in nature and currently extremely expensive to make at particle accelerators. Those that are created have limited storage time due to the imperfect vacuums used to store them here on Earth's surface. Highly reliable magnetic bottles would also be required even if a way is found for mass production because no contact can be allowed to normal matter without loosing the anti-matter fuel. In the rocket drive described by the author, high magnetic fields are used to direct the heavy charged particles (pions, muons) towards the rear to provide momentum transfer to the ship:

Several mission scenarios are described and the extremely high cost of anti-hydrogen production is mentioned, one should note that particle accelerators weren't designed to be anti-matter factories so things could look optimistic if more efficient ways are found however "clearly a very rich civilization is needed to produce this most compact fuel for starship propulsion".

Any venture to the stars at high speeds will have to deal with the possiblity of colliding with (hopefully tiny) particles along the way: gas&dust from the interplanetary medium and the interstellar medium, the author gives a rundown on the interstellar medium (ISM) which is mostly vacuum but still has gases and dust dispersed throughout the galaxy with an average density of mostly neutral/ionized 1 hydrogen atom / cm^3, some helium and traces of other elements, in our neighbourhood these particles are moving towards our Sun from Alpha Centauri at 20Km/s (from the reference the author gives). 1% of the ISM is made up of interstellar dust grains of carbon, nitrogen, oxygen, compounds of silicon, magnesium, iron covered with water, methane, ammonia, organic ices and other compounds, dust sizes vary from 0.1 to 0.01 micrometers. [CI: Visit this website for more info on the ISM].

This interstellar gas will produce slight drag and erosion on the forward surfaces of the ship, the dust could cause severe erosion as the ship is rushing at say 0.5c towards gas&dust. The effects of these collisions on the ship material is debated and needs experimental testing however various possible outcomes are described together with protection methods, some outcomes could be localised heat due to the impact and smoothing of the forward surfaces of the ship over time. In the previous photo shown of Daedalus, note the erosion shield on the forward part of the ship. The chapter finishes off by looking at interstellar electric and magnetic fields and a description of how a starship could use this magnetic field with charged wires for a round trip around a star. Several pages are devoted to interstellar ramjets and the Bussard ramjet which collects material (hydrogen) from space as it moves along for use in a fusion reactor for propulsion. The prospects for this method have shown this to be unviable: the scoop for eg would have to be 10000Km in diameter to collect enough hydrogen to get up to 0.1c. Another study has shown that the hydrogen atoms would also simply bounce back from the scoop and mostly not enter the collection point which defeats to whole purpose of the scoop.

In Part 3 of this book review, we'll look at the author's description of starship subsystems and possible mission scenarios (Chapters 5&6).

Part 1: Book Review - Prospects for Interstellar Travel

2010-01-30T11:44:00.004+11:00

Last week I received a copy in the mail of Prospects for Interstellar Travel by John H. Mauldin, 1992. So far I've finished reading the first four chapters and I'm impressed by the amount of thought that went into this book and I'm studying it in detail so decided to write up a comprehensive book review as it seems there aren't that many copies around these days available and helps me digest this book anyway. Although somewhat dated, most of the material is still relevant and covers the prospects and problems of interstellar travel and is highly readable with next to no maths in the main text, for those who like to see what the numbers have to say, there's a comprehensive Appendix as well.

This book is a good read for those who have wondered if it is feasible one day in the not so distant future for us to venture to nearby star systems and their exoplanets. John has done his homework in writing this book with many references along the way from earlier work by Forward, Johnson, Matloff to name a few. According to the short blurb about the author, John has worked at NASA in electronic power engineering for the Voyager missions among other things and has an engineering physics background. Let's get into it. Wherever I put in [CI: this means these are my own thoughts not the author's from the book.]

The book starts off with an introduction to general concepts dealing with interstellar travel explaining what destinations we might want to goto and within what Earth timeframe. This determines mission parameters in the first place (acceleration, speed, time, force, mass etc). Although Proxima Centauri at 4.2 Ly is our closest star, the author points out that "planning for a 10 Ly mission is more realistic" p6, as there are a dozen stars within this distance that could have habitable planets. It would be difficult to justify a mission to the Alpha Centauri system if we are just going to observe and do some scientific sightseeing because of the expected high cost of such a mission. [CI: I read a US magazine article that there's some chance NASA's funding to goto the moon might be scrapped. If the astronomers get lucky and confirm an Earth like planet in another star system within 10 Ly this would be one of the good reasons to justify the cost of such a mission]. There's a table where the author outlines 4 model missions on p9 which shows some of the problems especially the timeframes involved. Note that it makes sense to talk about mission timeframes in Earth years and not the relativistic dilated time for the travellers because we are (presumably) interested in science or material return to Earth.

Moving on to the first chapter, the author explores the basics of space travel explaining such concepts as force, thrust, acceleration, gees etc and newtonian orbital mechanics, the concepts of kinetic and potential energy with rocket propulsion as the focus. The author points out the inefficiencies of using chemical rockets but notes that "chemical rockets handle the most mass per unit of energy making high thrust good for liftoff (and not much else)" [CI: unfortunetly so far we have no other option that will provide this high thrust required to escape Earth's gravity well, more on this later]. I like rockets myself, there're big, they make lots of noise and they go fast ;-) however as the author points they are out of the question for interstellar travel due to the distances involved and the fuel/mass problem required by chemical rockets that they need to carry. It's pointed out that if a starship was 1000 tonnes, it would require at least 50 shuttle missions for the construction parts alone, in other words starships will not be built deep inside Earth's gravity well but in orbit or elsewhere in our solar system, unfortunetly this means having in place an extensive space infrastructure.

An outline is given on planetary gravitational sling shot mechanics and how this can be used to boost a starship's escape velocity to leave the solar system and also dicusses starship course corrections using stars: "If the speed is 1000Km/s (0.0033c), a starship aimed a close 10 million Km from the center of the star would be deflected about 2° from its original course" p32, and also mentions the interesting case of binary star flyby for speed reduction.

In the second chapter the author looks at advanced propulsion methods which carry more energy per kilogram than chemical fuels can or those that leave the fuel behind such as solar powered missions, nuclear fission/fusion, electric ion propulsion and solar sails. Past Jupiter's orbit the intensity of sunlight becomes too low to produce useful power for propulsion. Nuclear fission rockets have more than a million times more energy per kilogram that can be extracted from nuclear fuels such as uranium than from chemical fuels however for interstellar missions this still appears inadequate but looks useful for planetary missions in our solar system. Launching nuclear powered rockets from Earth's surface is not a good idea because of the problems dealing with radioactive waste and potential pollution hazards.

Fusion makes energy production 10 times better than nuclear fission making it a possible candidate for a starship powerplant and propulsion with less problems with radioactive byproducts. Fusion reactor fuel such as hydrogen, deuterium and helium-3 are available in low density in interstellar space and for any long interstellar mission living off the land makes sense. The author describes a fusion drive and how it could work and describes the Daedalus [CI: see Project Icarus] and Orion projects as case studies. A description is given for electric ion propulsion and mass ejector systems however these don't look promising for interstellar missions.

Photos: Right photo, bottom right is Daedalus.

Next we have the solar sail concept described in detail together with several references made to Gregory Matloff's earlier 80's work in this area. With solar sails the big advantage is that one doesn't have to carry fuel and we use sunlight's momentum for propulsion. Some of the problems outlined include the mass problem of the sail (Kg/m^2), the need to bring the solar sail very close to the Sun (to get the boost required to make interstellar trips viable) and issues with the structural fragility of the sail and connecting the sail to the starship. The mentioned designs so far are big (100Km diameter sail). As mentioned earlier past Jupiter's orbit the sunlight's intensity starts to become weak so everything needs to go just right when grazing the Sun's furnace. Towards the end of the chapter on p65, one sentence stood out which I'd like to quote:

"Like other missions involving long-term Earth support of a starship,

they require an extraordinary amount of social commitment."

In Part 2 of this book review, we'll look at Chapters 3 and 4 on relativity and more advanced propulsion systems described by the author.

Australia Day 2010

2010-01-29T15:52:00.000+11:00

It was another great day to be on the water on Australia Day with just about anything that floats on Sydney Harbour out for the day. Several flying machines turned up as well. Some shots from my camera (click on photos for bigger version):

The Known Universe

2009-12-24T02:01:00.001+11:00

Nuts and bolts (15/12/09)

2009-12-15T21:46:00.008+11:00

Some interesting items I came across recently worth a look at:

Interstellar Propulsion Research: Realistic Possibilities and Idealistic Dreams by Les Johnson gives an introductory rundown on the current status of possible interstellar missions and propulsion options. Apart from the mentioned warp drive (update: read this and this), all of the options are based on sound physics however all of them have severe technical and engineering difficulties to overcome if they are going to happen one day. Ironically getting the hardware required into orbit for these big spacecraft could be the biggest hurdle to overcome as using chemical rockets is expensive. The above options are based on our current understanding of Physics and we still have a lot to learn how nature really works.

The Final Frontier: The Science of Star Trek, interview with Lawrence Krauss. I read the first version of his book years ago and found it quite stimulating reading should interest all you Star Trek fans out there. I saw the world premiere opening of the movie at the Sydney Opera House and got a few autographs myself from the (new) Spock, Sulu and JJ Abrams, I liked the movie.

A Blueprint for a Quantum Propulsion Machine, here's also a review from Paul Gilster on this paper by Alexander Feigel. It remains to be seen if these so called "magneto-electric particles" do change the momentum of the quantum vacuum and thereby provide a means to change the orientation of a spacecraft without using propellant although many do this already using gyroscopes for eg however the physics if sound would be very interesting as this would provide another avenue to study the Quantum Vacuum. Another paper on this worth reading is here.

Been busy working on Sydney Harbour most days day and night as it is the busy season here. Some recent photos: Nice sailing boat in Farm Cove and checkout this sailing boat skipper going under the Anzac bridge, got his air draft right! Big tow job Bradley's Head outbound (click on photos for larger version).

Poem mystery author

2009-11-30T22:05:00.008+11:00

Although I can't say I'm a big fan of poetry, I do like a very few which deal with the stars, our Universe and (big surprise here) Man's quest to venture to the stars. When I was a small boy and pointed my telescope to Saturn for the first time, this was one of those moments you never forget for the rest of your life. After countless nights behind the eyepiece (it's quite addictive!), one eventually starts to ponder on thoughts on interstellar travel and watching StarTrek makes it worse ;-) There is one poem which I can't seem to find out who wrote it. I've posted the question to poem newsgroups and contacted various knowledgeable people but to no avail. It's engraved on the back on one of my brass compasses (Dollond London) which I got from a flea market a while ago next the Maritime Museum. Do you know who wrote this poem so I can give this mystery author proper credit?

One of the reasons why I bought this compass was because I liked this poem very much, if I didn't know better my first thoughts were either a Physicist wrote it or an author with deep thoughts on Nature. It talks about time, "a continuum moves and swirls..." (the vacuum?), the celestial sphere and life. Talk about big topics! The vacuum is central to Physics and today is still "beyond my inner sight and imagination" ie Physicists still don't understand it at the quantum level although they are getting better. Actually understanding the vacuum has been central to Physics most of our history, see this very interesting painting.

Some of you who work on Sydney Harbour may have noticed that Thor Gitta was docked in White Bay for quite a while (over a month), the mystery why she was there for all this time has been solved: she was waiting for this barge to unload her big load of cable:

Cosmology, The Big Bang and Entropy

2009-11-17T13:04:00.031+11:00

I went to Sean Carroll's talk yesterday at Sydney University. As many of you are aware, Sean is one of the bloggers on Cosmic Variance and is touring Australia for his talks. He also has an upcoming book titled From Here to Eternity: The Quest for the Ultimate Theory of Time.

Sean talked about all the big ideas that face Cosmologists these days and in particular Entropy and its relation to the evolution of our Universe starting from a state of low entropy / high order progressing towards a state of high entropy / low order. I didn't like his interpretation of time (particularly the "arrow of time") as mentioned in my previous post and as for the state of the Universe, this is ambiguous because we cannot observe the Universe from the outside hence there is no entropy for the Universe either.

Cosmologists have a fairly good idea what the state of the Universe was 1 second after the Big Bang however at "t = 0" (time cannot be defined here as there is no matter at this stage hence no clocks), no one knows as General Relativity breaks down however before the Big Bang? Sean speculated on an idea that our Universe may have begun from a single quantum fluctuation from the inherent energy of the vacuum, ie we live in a baby Universe an offshoot from another Universe. There was quite a good turnup and the lecture theatre was pretty full, all in all enjoyed the talk.

Still experimenting with $\LaTeX$ in Blogger using this script. Testing...

\[\tan(2\theta) = {2\tan\theta \over 1-\tan^2\theta}\]

\[\int \csc^2x\, dx = -\cot x+ C.\]

\[\ P_{r-j}=\begin{cases} 0& \text{if $r-j$ is odd},\\ r!\,(-1)^{(r-j)/2}& \text{if $r-j$ is even}. \end{cases}\]

\[\qquad \lim_{\alpha\to \infty} {\sin\alpha \over \alpha} = 0\]

\[\root n \of {\prod_{i=1}^n X_i} \leq {1 \over n} \sum_{i=1}^n\]

\[\ \cfrac{1}{\sqrt{2}+\cfrac{1}{\sqrt{2}+\cfrac{1}{\sqrt{2}+\dotsb }}}\]

\[\ \nabla \cdot \mathbf{D} = \rho_f \]
\[\ \nabla \cdot \mathbf{B} = 0 \]
\[\ \nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}} {\partial t} \]
\[\ \nabla \times \mathbf{H} = \mathbf{J}_f + \frac{\partial \mathbf{D}} {\partial t } \]

\[\ \boxed{m &= \frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}}\]

Review: LyX and viXra

2009-11-15T14:01:00.014+11:00

Been busy the last few days between work learning about LaTeX. Widely used by the academic and research community to write up high quality documents, scientific papers, books etc and especially useful for writting out mathematical formulae with their many special formatting requirements. The text it produces is beautiful.

I tested out LyX, which is a free Windows based Graphical User Interface (GUI) document processor for LaTeX and automatically will download MiKTeX during installation which is also required for your computer. Seems to work very well on my small laptop. Once you write up your document, you can preview it with Lyx's DVI previewer. Once you're happy with it, export the document in Adobe PDF format and you're done. LaTeX has many formatting tags if you look at the source code and although Lyx has also many GUI buttons, it's useful to sometimes type in the code by hand. There's also an excellent beginer's guide to LaTeX which I found handy called A Gentle Introduction to TEX. Great thing is, MiKTeX and LyX are both free for download! Google Documents also have the ability to insert equations and their online chart rendering feature has LaTeX command options (see links for the following):

A few days ago I also found out about the new viXra.org e-print archive. Unlike arXiv.org, this is open to anyone who wants to publish a paper and you don't need a "sponsor" (which is required by arXiv). This is great for people who aren't affililated with a research institution, university etc or can't find someone to endorse their paper. There are many Physics papers out there that are highly speculative and many academics aren't willing to be affiliated with a paper that at first appearances could be junk. The only problem is this doesn't help scientific progress. Their Why page explains all this in more detail. Because this is open to anyone, many junk papers will be found there however there are some interesting ones as well worth a read, all in all think viXra is a great idea. Worth keeping an eye on.

Attached photos: Students practicing survival at sea skills, liferaft deployment etc at the Qantas training pool, Sydney Airport.

What exactly is time?

2009-11-04T15:00:00.010+11:00

I came across today the following paper reviewed on the arXiv Blog and also on arXiv: Can the Arrow of Time be understood from Quantum Cosmology?

The question itself used as the title is flawed. There is no such thing as the "Arrow of Time" in Nature and after reading the paper suspect this will lead to another Not Even Wrong theory. This is a common misunderstanding in Physics so what exactly is time? It's about time we have a look. There's a wiki article however I prefer the explanation on p40 of the first volume of Motion Mountain:

"Time is what we read from a clock."

That's it! Your first intuition is correct ie you check your clock to find out what time it is. Note that clocks can be the Moon, the Sun, sundials, atomic clocks, Harrison's H1 clock etc.

Schiller goes on:

"Time is a concept introduced specially to describe the flow of events around us; it does not itself flow, it describes flow. Time does not advance. Time is neither linear nor cyclic. The idea that time flows is as hindering to understanding nature as is the idea that mirrors Page 71 exchange right and left. The misleading use of the expression ‘flow of time’, propagated first by some flawed Ref. 36 Greek thinkers and then again by Newton, continues. Aristotle (384/3–322 bce), careful to think logically, pointed out its misconception, and many did so after him. Nevertheless, expressions such as ‘time reversal’, the ‘irreversibility of time’, and the much-abused ‘time’s arrow’ are still common. Just read a popular science magazine chosen at random.

The fact is: time cannot be reversed, only motion can, or more precisely, only velocities of objects; time has no arrow, only motion has; it is not the flow of time that humans are unable to stop, but the motion of all the objects in nature. Incredibly, there are even books written by respected physicists that study different types of ‘time’s arrows’ and compare them with each other. Predictably, no tangible or new result is extracted. Time does not flow."

There you have it, if you were thinking of becoming a time traveller with exotic machinery don't waste your time. However time machines are available for purchase if you want one ;-), they only allow you to see back in time though and we are constrained to seeing the observable Universe.

Because light from the Sun for eg takes just over 8 minutes to reach us here on Earth, astronomical objects you see in the sky are essentially as they were when the light left them and because of the vastness of space and the speed of light, it takes time for the light from these objects to reach us. For eg light from our neighbour the Andromeda Galaxy takes 2.5 million years to reach us so if you look at it with a telescope (or with binoculars), you are seeing the galaxy as it was 2.5 million years ago. The bigger the telescope, the further you can see back:

At time t = 0, current Physics cannot explain what happened as the Physics cube mentioned in the previous post isn't complete. And before that? Roger Penrose gave a good talk in 2007 at Darling Harbour titled: What happened before the Big Bang?

Photos: Claudia I coming into Blackwattle Bay the other day delivering more concrete supplies.

Propulsion Physics and the future ahead

2009-10-29T18:47:00.019+11:00

I recently stumbled on a 2004 presentation by Marc Millis while doing some searches and is well put together. Unfortunetly NASA's former Breakthrough Propulsion Physics (BPP) Project (wiki article here) funding got cancelled a few years ago and today I read in Paul Gilster's Centauri Dreams outlining a report which recommends that NASA reinstate the (also cancelled!) NASA Institute for Advanced Concepts in one form or another, no doubt there are many reasons why they both got cancelled (which I think cancelling BPP was a big mistake regardless of NASA's new lunar or otherwise objectives considering the already minimal funding it received and the great job Marc and others put into it) however unfortunetly this means today that there are no substantially funded organisations dedicated to organising and researching advanced concepts or potential physics breakthroughs that could lead to making interstellar travel practical, economical and a viable proposition so we wait and see what mainstream Physics and individual researchers come up next.

Last night I watched the awesome Ares I-X launch and this is only the little puppy version of the big one they'll be using to launch crew to the Moon (however I'm reading in today's paper that the Moon program funding, yes you guessed could be cancelled!). No doubt money's tight for everyone at the moment but when I see how public money is wasted these days on other things with questional benefits to the public, I wonder...

I've outlined in a previous post why it is important for humans to settle on another planet (preferably on another Earth-like planet which means an interstellar journey to other star systems) and rockets just won't do the job (and are expensive, the Ares launch cost $445m according to the today's paper article).

So it's back to Propulsion Physics and first principles (or revised first principles?). There's no need for me to reiterate on Marc's presentation but the most important points are on p8 and p34:

Mass: Discover new propulsion methods that eliminate (or dramatically reduce) the need for propellant.
Speed: Discover how to circumvent existing limits (light-speed) to dramatically reduce transit times.
Energy: Discover new energy methods to power these propulsion devices.

"These goals are THE breakthroughs needed to conquer the presently impossible ambition of human interstellar exploration."

I'll talk about the Physics of these 3 points in a future post, what striked me in this presentation and what I wanted to mention in this post was on the last page:

"Science community does not address propulsion opportunities, but instead seeks a Theory of Everything. A propulsion focus increases options."

This is a good point, rephrased the Science community seeks to complete the Physics cube below:

Top right corner specifically. This is good as a Relativistic Quantum Theory of Gravity could lead to BPP and answer many unknowns in Physics and the Universe. However only seeking a unified theory of Physics isn't a good approach in my view. String Theorists have spent the last 25 years searching for their unified theory with so far a dead end (Peter Woit's book Not Even Wrong is a good read on this) and makes no new predictions in Physics that are verifiable and testable with the Large Hadron Collider. Even Einstein in his later years searched a unified theory of Physics to no avail. As pointed out earlier the Propulsion focus shouldn't be left out in the mainstream Physics research community. I'm not saying that all research into String Theories for eg should be abandoned (although myself I think it's a dead end) however there needs to be a more balanced focus to propulsion in mainstream Physics research, sometimes approaching a problem from a different angle can lead to productive results and in my view this is why cancelling the BPP Program at NASA was a huge mistake (where they should be leading the world by example). Practical and economical Interstellar flight may turn out to be impossible however while seeking solutions (as history shows in Physics) sometimes people stumble on other unexpected Physics.

What is the current state of affairs? As the BPP site mentions, "No breakthroughs appear imminent." There are many theories floating around however, either the theories haven't stood up to experiment or are inconclusive or there is no funding to test the theories put forth. Out of all the "crackpot theories" submitted each year, if one turns out to be correct, then this could change everything. There needs to be a funded program (like the BPP Project) that investigates and manages all this. For those who wish to dig deeper into all this a very good starting point is the following book: Frontiers of Propulsion Science. For those wondering checkout: What would a relativistic interstellar traveller see? I'll finish this post with a paragraph I like by Walter Drösher and Jochem Hauser in their paper (although I got a bit lost in their Extended Heim Theory and don't quite understand it):

What cats talk about at the Fish Markets

2009-10-28T00:54:00.001+11:00

There are quite a lot of cats at the wharf where the boats are kept and wondered what they sometimes talk about, now I know! :-))

Who said the sky's the limit and is Physics wrong?

2009-10-27T01:08:00.002+11:00

(23/10/09)

I was walking in the city earlier today and saw these ad billboards in the street:

Normally I wouldn't take a second look (I don't even have a credit card myself, think they're a waste of money) but saw a rocket in the stars so had to study it in detail! :-)) These ads actually give sound advice for anyone into Physics&Astronomy! When I looked at the first ad "Who said the sky's the limit?", immediate thoughts were, well Nature says what the limits are and the maximum speed that anything can travel in our Universe is the speed of light, C = 300,000Km/s.This applies not only to light but also matter, radio waves, information transfer etc. Protons, electrons etc are routinely accelerated to 0.99C at particle accelerators but never go over the speed limit.

Einstein's Special Theory of Relativity 101: "The speed of light in vacuum is always C, independent of the motion of thesource or of the observer".

This at first seems counter intuitive after all if you see a car moving at 100Km/h on the freeway then light leaving their headlights should be travelling at 100Km/h + C right? Wrong, light still travels at C! (Don't worry about the air makes very little difference you could do this in space for eg). This makes perfect sense if you think of everything you see around you immersed in the vacuum and this vacuum (which is a complicated "quantum fluctuating soup") doesn't allow light to travel faster then C. Strange things happen as you travel 1/3C or faster (time dilation etc...)

Second ad basically was telling me that although exploring the Universe with telescopes etc is good, get off your butts and build some ships to do some serious exploring beyond the solar system! ;-) Given the distances involved in our Galaxy, the speed limit (C) imposed on us by the vacuum is problematic. Closest star is 4.2 lightyears away for eg however if you're planning your next trip to Alpha Centauri don't despair this isn't the end of the story there are different types of vacuums which are under study... even Roger Penrose (who wrote the masterpiece The Road to Reality) recently mentions that our current theories are "wrong" although some don't agree with all he says it's interesting reading:

http://discovermagazine.com/2009/sep/06-discover-interview-roger-penrose-says-physics-is-wrong-string-theory-quantum-mechanics

Looking forward to some more American Express credit card ads! ;-)

50 years of space exploration map‏

2009-10-27T00:56:00.001+11:00

(17/10/09)

Checkout this beautiful map illustrating where our probes have been so far in the solar system:

http://wanderingspace.net/2009/10/50-years-of-space-exploration-map/

There's a zoomable version at:

http://books.nationalgeographic.com/map/map-day/2008/09/18

Very nice. Checkout the scale at the bottom, you'll see Voyager 1 at 10 billion miles (16.5 billion Kms) way past Pluto's orbit heading into interstellar space and this is the first human made object to leave the solar system. It was launched in 1977 and is still transmitting! No batteries onboard, the probe is powered by Radioisotope Thermoelectric Generators (RTGs):

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator

which should generate electricity for the probe till 2025, at this distance from the sun, solar panels don't work. I think if ET finds the onboard golden record they should have a box office sellout at the movies on their planet! ;-)

Attached photo: Suncat getting ready for the Manly fast ferry service.

Greenwich Longitude turns 125 years old!‏

2009-10-27T00:50:00.001+11:00

(14/10/09)

The Prime Meridian (Longitude 0°) at Greenwich Observatory turned 125 years old! It was born on the 13th October 1884, read about it at:

http://backreaction.blogspot.com/2009/10/125-years-of-greenwich-longitude.html

Gigagalaxy Zoom project‏

2009-10-27T00:42:00.001+11:00

(12/10/09)

Here's a useful website if you haven't got the time to do some stargazing or just wondered what's at the centre of our galaxy, checkout the recently released:

http://www.gigagalaxyzoom.org/

Has high quality photos of our stellar neighbourhoods and you can zoom in and out from some photos etc. If you don't have the time to visit the centre of our galaxy, here it is:

http://www.eso.org/gallery/v/ESOPIA/Quasars/phot-46-08-fullres.tif.html

Don't get too close though, there's a black hole at the centre ;-)

Attached photo: Steve Irwin leaving Sydney today http://www.seashepherd.org/

Submarine neutrino communication‏

2009-10-27T00:35:00.001+11:00

(07/10/09)

Here's some interesting reading for you submarine buffs out there:

http://www.technologyreview.com/blog/arxiv/24203/

This Physicist published a paper on how to use neutrinos as a possible effective communication method for submarines underwater to receive messages only. As you know only extra low frequency (ELF-VLF) radio waves can be used for communications by submarines underwater as the higher frequencies get severely attenuated and because of the very low frequency, only very low bit rates can be used. Neutrinos are particles that are created in certain nuclear reactions and radioactive decays, they travel close to the speed of light and interact very rarely with normal matter. Although we don't realise it, right now your body is emitting roughly 400 neutrinos per second due to the naturally occuring radioactive isotopes of Calcium and Potassium in your bones. You are basically neutrino transmitters.

Attached photos:
- Someone who named this barge "Nebula" must be into Astronomy ;-)
- This catamaran had a Compass Adjuster onboard the other morning, heard them call up Harbour Control on Ch13 when they were using transits in the channel. I better finish the course ASAP!

Saturn at equinox and the same colour illusion‏

2009-10-26T23:49:00.001+11:00

(04/10/09)

Checkout these interesting Astronomy Picture of the Day photos:

http://antwrp.gsfc.nasa.gov/apod/ap090930.html
http://antwrp.gsfc.nasa.gov/apod/ap091004.html

Goes to show when it comes to Science, appearances can be deceiving, don't always trust your brain ;-) Attached photos: Lithgow today under Anzac bridge (with a nice new Rosman Ferries paint job) and tugboats busy with CSL Pacific a few days ago 6am in White Bay, now this ship definately needs a paint job.

Internal Combustion Engines MIT OpenCourseWare now online‏

2009-10-26T23:39:00.001+11:00

(24/09/09)

For those interested, MIT has released today free online course notes for internal combustion engines including diesel engines:

http://ocw.mit.edu/OcwWeb/Mechanical-Engineering/2-61Spring-2008/CourseHome/

Click on "Lectures notes" on the sidebar to donwload individual lecture notes or you can download the lot. Last lecture explains hydrogen fuel cells and other techonlogies. Attached today's harbour photos.

New rocky exoplanet found and first detailed photos of an atom!‏

2009-10-26T23:30:00.001+11:00

(18/09/09)

Lots of good things happening in Physics & Astronomy this week! I read an article in today's MX newspaper but check the articles below for more info:

http://www.eso.org/public/outreach/press-rel/pr-2009/pr-33-09.html
http://www.centauri-dreams.org/?p=9451

The Astronomers did a good job and confirmed that a planet outside our solar system (500 lightyears away) is rocky (not like Jupiter size planets for eg made of gas). Might be a bit too hot for your comfort though so lets hope the Astronomers get lucky and find another Earth-like planet soon because this one is starting to get too crowded ;-) Have a look at these first detailed photos of the electron clouds of carbon atoms:

http://www.insidescience.org/research/first_detailed_photos_of_atoms

The nucleus itself (protons and neutrons) is too small to be seen, between the electrons and the nucleaus itself it's empty space.

Attached photos: ships docked in White Bay last Saturday night. Reef Endeavour has been there for months and Golden Mermaid with the red flashing light on top stank like fertiliser or nitrates, busy discharging into lots of tankers waiting at the wharf.

Lucas Heights nuclear reactor open day‏

2009-10-26T23:23:00.003+11:00

(13/09/09)

In case you didn't know the Lucas Heights nuclear reactor is having an open day for the public on Saturday 19th September (thanks to Tony for the info):

http://www.ansto.gov.au/

Not sure if I can make it that day but if I'm free I'll be bringingwith me my specially modified geiger counter
:-) I checked again tonight (Sunday) how many ships there are anchored off Newcastle on http://marinetraffic.com/ and I counted over 40 ships!!!?! Talk about busy little Harbour!

Live Ships AIS Map online‏

2009-10-26T23:13:00.001+11:00

(10/09/09)

Checkout this website:

http://marinetraffic.com/

Shows on the map live AIS information of vessels around the world including Sydney. Checkout how many ships there are outside Newcastle waiting for coal!! You'll see some of the Sydney Ferries for eg also have AIS and you can click on the icons to get a photo of the boat and other info if available. Attached photos: Cronulla Ferries.

Degaussing range and nuclear powered ships‏

2009-10-26T23:06:00.001+11:00

(07/09/09)

For those who have to sometimes give commentary during the cruise, here's your big chance to impress your passengers by telling them about the degaussing range at Steele Point, Rose Bay where you sometimes see Navy ships hanging around, find out what's going on:

http://www.brighthub.com/engineering/marine/articles/43712.aspx
http://www.brighthub.com/engineering/marine/articles/43714.aspx

Another interesting article on nuclear powered ships:

http://www.brighthub.com/engineering/marine/articles/26364.aspx

If the hydrogen fuel cell water taxi doesn't kick off at least there's the nuclear powered water taxi option ;-)

Learning resource for Marine Engineers‏

2009-10-26T22:55:00.001+11:00

(04/09/09)

Anyone studying marine engineering subjects might find this website useful:

http://www.marinediesels.info/

Although it's geared towards the big ship engines, it has lots of relevant info for smaller ones and associated machinery with neat diagrams/animations.

First Hydrogen Fuel Cell Water Taxi‏

2009-10-26T22:48:00.001+11:00

(03/09/09)

A few months ago you read about the first hydrogen fuel cell commercial charter boat and aircraft in Germany, here's the first water taxi launched in 2003 using this technology:

http://www.marinelog.com/DOCS/NEWSMMIII/MMIIIOct16d.html

Build some nuclear/solar/wind/ocean current power stations to make lots of electricity (these don't pump CO2 into the atmosphere) in order make hydrogen gas from sea water, hydrogen gas filling stations and you have a true zero emission transport system. Another option looked at is an engine that burns hydrogen gas(highly flammable) in a combustion chamber directly rather than using fuel cells to make electricity which drive electric motors:

http://www.atzonline.com/index.php;do=show/site=a4e/sid=5666422124a9fbc2f268fd257932636/alloc=1/id=9413

Photos attached: lifeboat drill today at the maritime museum. Note the plaque has a small typo, should read 21.2KW

How many barges can you tow at once?‏

2009-10-26T22:18:00.001+11:00

(01/09/09)

Checkout these interesting articles:

http://cargolaw.com/2009nightmare_margaret.html

Talk about heavy duty tow job, can you count how many barges they are towing?!?!! And photos about a collision between two ships M/V Marti Princess & M/V Renate Schulte June 2009:

http://cargolaw.com/2000nightmare_singles.only.html

Onboard the Columbian Navy training ship ARC Gloria‏

2009-10-26T22:10:00.001+11:00

(30/08/09)

If you haven't heard the Gloria is in Sydney for another 4 days and is docked in Circular Quay, she's

open to the public (free entry) and went onboard today, unfortunetly I couldn't sneek in the engine room
to take some more photos because of tight security but here are some to clog up your mailbox ;-)

Bee celestial navigation‏

2009-10-26T21:42:00.002+11:00

(30/08/09)

Have you ever wondered how bees manage to tell the other bees where the best flowers are to make honey? It turns out they are very competent at using our closest star and the moon to tell the other bees (by fancy bee dance work) in what direction and distance the flowers are, they even outsmarted the professor while he was doing his bee experiment! So spare a thought next time you put honey in your tea

"It takes about 6 bees life work, and thousands of miles flown, to make one teaspoon of honey"

http://www.space.com/searchforlife/090827-seti-bees-navigation.html

Photo: Another wedding on the Pontoon, Opera House dropoff.

The Matrix revisited: Is the Universe a giant computer?

2009-10-26T20:28:00.001+11:00

(27/08/09)

A nobel prize winner Physicist has recently published a theory (which has problems) that basically concludes Einstein's views that Nature or "God does NOT play dice" when it comes to quantum mechanics ie quantum mechanics is deterministic rather than probabilistic and there is a hidden mechanism that determines if a state is in A or B for eg rather than say 50% chance for state A and 50% chance for state B. Without getting into the physics, it says

"The universe is a cellular automaton in which reality is simply the read out of a giant, fantasticallycomplex computing machine"

http://www.technologyreview.com/blog/arxiv/24044/

You bloody hope that this computer doesn't run on Windows Vista!!! hehe ;-)))
Attached photo: today True Blue pulling into King Street Wharf, still whale watching season.

Ultimo Science Festival starts this friday‏

2009-10-26T20:18:00.001+11:00

(20/08/09)

In case you people didn't know, the Ultimo Science Festival kicks off this friday night at the Powerhouse Museum with "Psychology, live jazz, physics, space-art, dark matter and more…", be there or be square:

http://www.ultimosciencefestival.com/usf09/

I'll be there ;-) Attached some recent photos dumped from my camera:

Photo 1: Golden Georgia in Athol Bay.
Photo 2: Beautiful ferry "Bundeena" at the Fish Markets.
Photo 3: In the bow thruster compartment on Bella Vista.

A moonbow and a rainbow‏

2009-10-26T15:37:00.004+11:00

(10/08/09)

You have all seen a rainbow and perhaps a double rainbow but have you seen a moonbow at night? This time it is the sunlight reflected from the Moon (moonlight) which creates the effect via refraction from water droplets, checkout this excellent video:

Attached some photos sent by Pete, one of my former students who skippers the ferry Sun on the Hawkesbury River out of Brooklyn. This ferry being just under 12m only requires Coxswain, goes to Dangar Island, Wobby Beach and back 364 days a year early morning till evening. There's also the Hawkesbury Explorer and Hawkesbury (both Master 5 boats) which do regular cruises up the river including the last riverboat postman run. I used to work there for a year after I just got my Master 5 ticket a few years ago, all good fun.

Are there realistic options for going to the stars?‏

2009-10-26T15:23:00.001+11:00

(25/07/09)

Some of you may have wondered when looking up the night sky if interstellar flight is at all possible or is it the dreams of couch potato StarTrek fans? We went to Moon, hopefully Mars not too long, what's next? Here's a recently written readable article that gives a good introduction on the subject:

http://www.peregrinus-interstellar.net/index.php?option=com_content&task=view&id=149&Itemid=28

In short yes there are currently options that could work given our current understanding of Physics, however they would be prohibitively expensive, impractical, too slow etc. The other option is to improve our knowledge of Physics to make interstellar flight less expensive, practical and come up with a fast transport method so the question is still open, good for us! Attached photos: Saw this interesting dredger ship De Bougainville in White Bay yesterday, they're doing work in Botany Bay:

http://laperouse.info/?p=551

40 years ago people were on the moon!

2009-10-26T15:12:00.004+11:00

(20/07/09)

Well it's all over the news so no need to elaborate but here are some interesting links for you people if you missed it:

http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html
http://www.space.com/news/090714-apollo11-40th-ann-druyan.html

I like the interview with Ann Druyan (widow of Carl Sagan) especially the last bit:

"pure scientific research can change and even create vast amounts of wealth for us. The Maxwell equations begin as an exercise in mathematics, how to make an equation more beautiful. And they end by completely creating, single handedly, the communications revolution that has made our age."

Attached photo: Tyco, cable layer ship getting refuelled by Amorena last night inWhite Bay (notice the red lights on top).

Re: The Captain is always right‏

2009-10-26T15:04:00.001+11:00

(15/07/09)

Someone forwarded this classic video, most of you have probably seen it already:

The USS Montana should have the following plaque as some boats have in the wheelhouse ;-)

Standing Orders
1) The Captain is always right.
2) If the Captain once isn't right, goto 1)

Attached photo: boat rounding Peacock Point today outbound, roomy wheelhouse!

Stability problem‏

2009-10-26T14:49:00.001+11:00

(30/06/09)

Checkout the interesting slideshow of this boat rolling over while at the berth! The crew might need a bit of brushing up on stability...

http://www.heimsnet.is/iceship/hsmyndir/Slideshow/index.html
http://www.cargolaw.com/2009nightmare_seaflower.html

Hovercrafts at Balls Head‏

2009-10-26T14:42:00.001+11:00

(14/06/09)

Saw these 2 hovercrafts today wizzing around Balls Head, one has an Army colour scheme... Gimme one of these for Christmas! :-) Looks like good fun...

The physics of rogue waves‏

2009-10-26T14:37:00.001+11:00

(06)/06/09)

Might be worthwhile reading this article on the physics of rogue waves:

http://ptonline.aip.org/journals/doc/PHTOAD-ft/vol_62/iss_6/62_1.shtml

Don't like the look of the huge wave in the photo coming towards the ship... beam me up Scotty now! ;-) Attached photo: you know when it's winter in Sydney when a fairy penguin turns up while rowing to work!

Pacific Adventurer containers found + Drill rig in Darling Harbour‏

2009-10-26T14:32:00.001+11:00

(03/06/09)

Here's an interesting page on the Pacific Adventurer incident with underwater shots by the Navy of (what looks like) the missing ammonium nitrate containers:

http://cargolaw.com/2009nightmare_pacific.adv.html

If you're wondering what the drill rig "Sea Lift 2" is doing in Darling Harbour, they're doing core samples for a tunnel for the possible metro link if it goes ahead...

FW: Jenneau Leaving Southport Seaway on Friday‏

2009-10-26T14:24:00.001+11:00

(29/05/09)

Someone forwarded these photos, crazy...

"This guy decided to commence a passage from Southport to Yeppoon yesterday. The forecast was seas 9 to 10 mtrs with a storm warning with winds that had at times been recorded at 61 kts at the seaway. He attempted to go out the seaway at 3pm May 22. Police say he may be charged."

World's first zero emission passenger boat‏

2009-10-26T14:15:00.001+11:00

(21/05/09)

Checkout the world's first ZERO emission passenger boat (25.5m long) using hydrogen fuel cells:

http://www.zemships.eu/en/

Doesn't use diesel fuel, no emissions, fill up with hydrogen gas instead, a full tank of 50Kg of hydrogen will run the boat for 3 days, has twice the fuel efficiency of a standard boat with diesel engines, non-polluting and virtually silent (electric motor drives the propeller, some new ships use electric AZIPODs:

has been certified for commercial operations to carry 100 passengers. Where do you get hydrogen gas from? Water -> H2O. Where do you get water? Look over the side ;-) The only ding is you need lots of electricity to separate in commercial quantities the hydrogen from the oxygen in the water molecule however as you know there are lots of non polluting methods of generating electricity going around, wind, solar, ocean currents, nuclear etc... Of course hydrogen goes with a bang when ignited so they must have worked out lots of safeguards to keep the German Lloyd people happy...

http://www.archive.org/details/hindenberg_explodes

Should have one in Sydney Harbour going around, give it a test run...

Pirate article‏

2009-10-26T14:11:00.001+11:00

(21/05/09)

Talking about pirates, this article was in yesterday's Sydney Morning Herald if you missed it:

http://www.smh.com.au/national/navy-rescues-a-princess-from-pirates-20090518-bcpe.html

this tanker would make good use of a Force 1000 triple barrel Aqua Blaster ;-) or any of the other gadgets mentioned in the previous Email... Thanks to those who got back with other pretty funny ideas :-))

Non lethal anti-Pirate deterants‏

2009-10-26T14:01:00.002+11:00

(19/05/09)

Check out p27 of this month's Maritime Reporter online magazine:

http://dwp.marinelink.com/pubs/nwm/mr/200905/

With pirate attacks becoming a big problem for merchant ships they got some nice new toys such as the (my favourite) "Force 80 Water Canon", looks impressive and can be controlled with a joystick "point&shoot" and can be combined with the radar system/video camera so you can hide inside the ship while the pirates get grumpy etc... nice. Or try the "Mobile Denial System", something right out of 007 slimmy chemical system so it will make it difficult to board your boat... or if you want to feel extra safe you can even hire ex special forces personnel to ride along your boat, the list of toys goes on... advanced night vision, "sound weapon" etc... just make sure you're in the cone of silence before activating this weapon ;-) Anyone got other bright ideas? I was thinking have a "Force 1000 Water Canon" with "bubble bath" soapy solution and fine metal particles for pirate radar jamming so when mixed with the high pressure water the pirates' boat gets engulfed by a huge "bubble bath" and can't see by radar either? ;-))

Ok it was a thought, better get back to the Hubble and space shuttle...

Nice sailing boat‏

2009-10-26T13:53:00.001+11:00

(14/05/09)

Was at the Rocks on Monday night and saw this boat berthed at Campbell's Cove. You'd have to pay me to go on a sailing boat ;-) but this one is quite nice...

If you're missing all the action on NASA TV, the space shuttle is about to catch a big telescope orbiting this planet:

http://www.nasa.gov/multimedia/nasatv/index.html

More photos‏

2009-10-26T13:45:00.001+11:00

(29/04/09)

Been a while since I sent you people some maritime action photos ;-) Last weekend did some volunteer work in the engine room on Cape Don. We fired up the engine for the backup fire pumping system which is in the steering room and tested all the fire hydrants onboard etc... someone took a couple of photos:

http://www.mvcapedonsociety.org.au/weekends/we-18-apr-2009.html

Attached photos of one of the boats I work on, slipped today.

Queen Mary2 in Sydney‏

2009-10-26T13:37:00.003+11:00

(26/02/09)

Here's some photos taken today. QM2 is docked at Woolloomooloo while Saga Rose was berthing in CQ (this is her last trip as she's being decomissioned). QM2 is too big to fit in my camera so had to paste 2 photos together ;-)

http://en.wikipedia.org/wiki/Queen_Mary_2

http://en.wikipedia.org/wiki/Saga_Rose

Does anyone know how I could sneak onboard without getting into trouble so I canhave a peak at the engine room?

Re: Many Earths + Sharks in Sydney Harbour‏

2009-10-24T16:55:00.001+11:00

(21/02/09)

Everyone knows about the recent shark attacks we've had in Sydney lately but I caught one shark red handed on camera trying to have a feed. I saw one in Rose Bay a couple years ago chasing a runabout, obviously the shark must have been really hungry, I've never seen a shark so big before, it was huge!

Does anyone know why there are so many passenger ships coming to Sydney lately? The paper on thursday was saying 27 passenger ships are coming in the next 27 days didn't say much else. Queen Victoria is in CQ at the moment and Queen Mary is coming as well. Just as we were dropping off at casino last night, the Tahitian Princess was departing Darling Harbour...

Following up the many Earths post, for those interested:

- Where are these Earths? NASA is launching its Earth hunter Kepler mission next month (March 5):
http://kepler.nasa.gov/

- How do we get to them? Those into Propulsion Physics might be interested in this year's SPESIF in a few days time:
http://ias-spes.org/SPESIF.html

Many Earths + Rhapsody of the Seas photos

2009-10-24T16:34:00.003+11:00

(‏ (17/02/09

Hi everyone,

There's an interesting article today in the Age worth reading:

http://www.theage.com.au/world/et-there-goes-the-neighbourhood-20090216-8984.html

The idea that there are many Earth like planets scattered throughout our Galaxy isn't new however Astronomers are getting closer to confirming the existence of other Earths via better telescopes/techniques etc. Back in 1695 the famous Astronomer/Physicist Christiaan Huygens wrote about these Earths (click on picture for hi res version):

Most people will agree with the Astronomer's assessment when they actually get to see a detailed photo of one of these Earths when they launch space based interferometers and this would convince the majority of the public. The question is what do we do once we have confirmed there are many Earths in our Galaxy? We can sit down and talk all day about possible ETs, aliens, microbes etc etc but the best way to answer these questions would be to actually go there by sending probes or people to study it in detail. And why bother with all this anyway? Waiting 2000 years for data is too long and it looks like we're running out of $cash at the moment...

Apart from its scientific value there's a more serious side to all this. Some people would argue that the only way for us to survive is by spreading to new lands (looking back in history). Overpopulation, lack of resources, asteroid impact, nuclear holocaust, WWIII, famine, desease etc are all a possiblity in the future and having all your eggs in one basket ie 6.8 billion people (March 2009) all on one planet isn't a good idea.

All that's required to colonize this new Earth would be an engine that would allow interstellar travel to be practical and economical based on new Physics. As mentioned in a previous post, our current understanding of Physics doesn't allow this (rockets etc aren't feasible solutions as far as interstellar travel is concerned) however there's always the fine print at the bottom of the page worth reading ;-)

Also attached some photos of Rhapsody of the Seas anchored in Athol Bay last Wednesday. Rotterdam and Europa took up CQ and Darling Harbour so she couldn't berth. We were doing passenger transfers from Millers Point customs tent to the ship round the clock, I swapped with the next Captain at 5.30 am! Interesting to note that when the passengers/staff board/dissembark they have cards they have to swipe to get in or out the barriers inside so the onboard computer knows exactly who's onboard.

Why is the sea blue? (02/02/09)

2009-10-24T16:15:00.003+11:00

Anyone wondered why the deep ocean is blue? The water in a glass doesn't look blue... What's going on? Reflection from the blue sky? Since you guys work on the water you better go find out! Stephan in his 29th January blogpost gives a good article explaining how "Beautiful physics is hidden below the blue surface of the ocean.":

http://backreaction.blogspot.com/2009/01/water-is-blue-because-water-is-blue.html

There's also a good photo showing the difference between normal water (H2O) and heavy water (D2O). Deuterium is a heavy version of hydrogen in the water molecule, and makes for about 0.015% of all naturally occurring hydrogen in the oceans on Earth. In 1944 a commando sabotaged the ferry Hydro in Norway to stop the Nazis getting hold of a shipment of heavy water for their nuclear physics research:

http://en.wikipedia.org/wiki/SF_Hydro

They made a movie of it on DVD called "The Heroes of Telemark".

Diamond Princess leaves Sydney (30/01/09)

2009-10-24T15:48:00.001+11:00

After comtemplating on the 10g paper boat decided to go have a look at a bigger boat after a few reds at the Orient Hotel last night :-)) She left about 2100, anyone notice the 4 radars to cover the blind sectors! Also has 3 bowthrusters and stern thrusters:

"At 290 metres and 116,000 gross registered tonnage, the Diamond Princess is the second largest cruise ship to visit Sydney behind the Queen Mary 2."

International paper boat competition‏

2009-10-24T13:22:00.001+11:00

Anyone wanting to put their Master 5 Stability skills to good use, here's your big chance. Your mission (should you choose to accept it): is to build a ship made of paper that weighs <= 10 grams to carry a load > 5132 grams (world record), do you have what it takes?

http://www.paperboat.de/

Also attached some photos of Australia Day.

The robot that walks on water‏

2009-10-24T12:47:00.001+11:00

Hi everyone,

You have to see it to believe it!

http://nanolab.me.cmu.edu/projects/waterstrider/

This would make an excellent lure when going fishing ;-) Also attached a photo of NYE, anyone notice the boat with the telescope and falling star light display? Best one ofthe lot I reckon! :-))

Interstellar travel, matter-antimatter rockets, fusion ramjets etc‏

2009-10-24T12:39:00.002+11:00

Hi everyone,

Any of you guys StarWars fans? Decided to goto the PowerhouseMuseum checkout their StarWars gallery and ended up having a field day! :-)) Apart from the models they used in the movies the most interesting display was the one with the concepts previously thought so far based on real Physics dealing with interstellar travel.

Although the concepts thought up so far based on our current understanding of Physics could work, none of them are practical: the matter-antimatter rocket for eg is nearly the size of Texas! All of them rely on the momentum principle (throw something backwards to go forwards) and all of them are bound to sublight speeds due to special relativity: the vacuum of space imposes a maximum terminal velocity, the speed of light, to everything in our Universe. This is a big problem (if you want to travel to nearby stars fairly fast), the 2nd closest star from us is Proxima Centauri at 4.2 light-years which means it takes light 4.2 years to travel to Proxima, all starships would take much longer because matter (the ship) cannot go faster than light.

The good news is our lack of understanding of the Physics of the vacuum of space and why the vacuum imposes this speed limit in nature means that this isn't the end of the story. The world's largest particle accelerator (the LHC) might give some clues when it becomes operational hopefully later this year...

Testing blogsite

2009-10-24T11:36:00.000+11:00

This is a drill!