General Relativity

Originally posted by sonhouse
Here is a nice problem for relativitists: I just heard about these cosmic rays coming in from across the universe, billions of LY away but have so much energy, they are going almost at C. They said if a light beam takes 300 million years to travel that many light years, this cosmic ray would take 300 million years, and ONE microsecond more.
So how much in must take something like matlab to do properly. Anyone got one of those advance math programs?

You made such a huge approximation by making 3.1536E7 = 3E7 (an error of 5.12% ) that I don't think any answer will make sense anyway. 🙂

Got to admit that it would be interesting to know 1.67262158 × 10^-27 kg will be that close to the speed of light (extreme approximations aside).

Originally posted by wormwood
the speed of light is not constant, it depends on the medium, and can be as slow as only a few meters per second.

but general relativity is based on the notion that there exists a top speed which is constant, and in practice that's assumed to be the speed of light in a vacuum. there's nothing to suggest that speed of light in vacuum ...[text shortened]... akes no assumptions of what the actual top constant speed is, only that there is one.

Wouldn't it depend on what its moving through also?

Doesn't gravity also move at the speed of light? That should mean it would have to be contant or pretty darn close to it I think.