# Radial expansion of the universe and the speed of light

1. Dec 15, 2011

### AugustusM

Just wondering if the two are fundamentally linked ?

If the universe is in the shape of a 3 sphere and if it's radius represents time, then does the expansion rate of the radius determine what the speed of light is ?

I've also read elsewhere that the passing of time is linked to the expansion of the universe along it's radius. If the expansion of the universe stopped, would time stop. With timed stopped would light and photons then stop moving ?

2. Dec 15, 2011

### michelcolman

Maybe it's the other way around. The speed of light might be determining how fast the universe appears (to us) to be expanding. After all, the speed of pretty much any process here on earth (down to the speed of chemical and even atomic processes, which still depend on photons and other particles being transfered back and forth at a small scale) can probably be linked to the speed of light. If the speed of light changes, our clocks (no matter what they are made of) and our subjective perception of time will change too. If our clocks slow down (because the speed of light slows down), but the universe keeps merrily expanding at its normal rate, it will appear to be accellerating. Just a random thought...

3. Dec 15, 2011

### AugustusM

Just a simple logical conclusion

1. Just say that the speed at which the radius of the universe is increase is the same as the speed of light.

2. If the universe stops expanding, then time stops.

3. If time stops, then all movement stops.

4. Even light cannot move in this scenario.

5. If the speed of light is now zero (as the universe's radial increase velocity is now zero also) then this means that light cannot move anyways.