Tuesday, October 27, 2009

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


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:


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

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