| scottie said:
@ mysticwolf - it depends on your definition of immortal. An observer on Earth would see you living for millions of years, but for you it would go by in the blink of an eye. It would not give you extra time to do stuff.
@ jay - wall of text commencing.
Relativity (ie what I was describing above) started with the assumption that, no matter what speed you are going at, you will always observe light going at a constant speed, which depends on the material it is traveling through, and is 3*10^8 metres/second in a vacuum and lower in materials. How Einstein decided that this assumption was a good one to make is quite beyond my understanding.
Fortunately, there is now a significant amount of experimental evidence for relativity, implying that Einstein was almost certainly right to make such an assumption. It was demonstrated that if you syncronise two very accurate clocks, and send one on a plane to do some laps of the world, and keep the other in it's original place, the moving clock will start to lag behind. As I mentioned ages ago, there are particles created by incoming sunlight that decay too quickly to reach the ground without relativity. But because they are going fast enough, time slows down for them and they can make it to the surface, or even underground before they decay.
The mathematics of relativity all follows from the assumption that the speed of light is constant, and from the assumption that certain types of events must be observed by everyone,if I observe that two spaceships collide, then someone who is moving at 90% of the speed of light must also observe the same thing. If the speed of light were constant, but the effects associated with relativity (moving objects act as if they had increased mass, moving clocks run slower and moving objects shrink) did not occur, it would be possible for a stationary observer to see someone crash their spaceship and die, but a moving observer see them avoid a collision and live. This is an irreconcilable difference.
This doesn't really answer the question of 'why' it just changes it from 'why dont we age' to 'why do we observe the speed of light to be constant' and I'm sorry to say, I don't know. I'm not sure anyone does. Why is always the hardest question in physics. |
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