27 Oct '07 20:06

OK, this is neither a poser nor a puzzle. But I know all the smart people hang out here so I thought I'd ask.

I'm trying to understand relativity a little better, and have been reading some books.

One of the foundations of relativity is that the speed of light (in a vacuum) is a constant. From this it can be then shown that the speed of time is variable (i.e. time slows as speed approaches c). I understand all that (mostly), and the math behind it.

This all seems counter-intuitive to most people, who instead want to suppose that a) time is constant and b) the speed of light varies.

Can anyone propose an informal proof by contradiction to show where this breaks down. That is, assume:

a) Time is constant and cannot vary

b) "c" can vary

and demonstrate these lead to invalid conclusions?

I'm trying to understand relativity a little better, and have been reading some books.

One of the foundations of relativity is that the speed of light (in a vacuum) is a constant. From this it can be then shown that the speed of time is variable (i.e. time slows as speed approaches c). I understand all that (mostly), and the math behind it.

This all seems counter-intuitive to most people, who instead want to suppose that a) time is constant and b) the speed of light varies.

Can anyone propose an informal proof by contradiction to show where this breaks down. That is, assume:

a) Time is constant and cannot vary

b) "c" can vary

and demonstrate these lead to invalid conclusions?