Thread: Big bang

I have a question. If nothing can travel faster than the speed of light; Then what is the explanation for the rapid expansion of the universe described after the big bang? I read that the universe expanded at a rate many times the speed of light.

Originally Posted by bronco

I have a question. If nothing can travel faster than the speed of light; Then what is the explanation for the rapid expansion of the universe described after the big bang? I read that the universe expanded at a rate many times the speed of light.

Nothing with mass can travel faster than light.
With regard to the BB expansion it was space itself that "moved" so fast.

Nothing can travel through space faster than light. The expansion of the universe is a metric expansion of the space between everything. Nothing is moving through space, there's just more space created at a rate which means that light will never be able to traverse the increasing distance.

Hi bronco, this is a very common question and something most of us have had to learn, ok so here is my attempt at a simple answer: Despite the rapid expansion, nothing actually exceeds the speed of light, this is because it is the space between the galaxies which actually expands giving the impression of greater distance between them. Since this happens everywhere it appears as a multiplied effect the further away an object initially was, this means that there are areas of the universe that may appear further away than it seems they could have possibly travelled during the time that the universe has existed.

Now if none of that makes sense don't worry, took me ages to get my head around it but you'll get there.

Here is a far more accurate answer which has helped many of us, thanks again here SpeedFreek, he wrote this for us all:
Looking back in time....

Is space itself still expanding at the speed of light?

Originally Posted by sculptor

Is space itself still expanding at the speed of light?

Space doesn't expand at a speed. It is a proportional increase in distance over time. So the distance between two points will increase by some (small) percentage every year. If two points are further apart then the increase in distance per unit time will be larger; hence the apparent increase in recessional velocity with distance. The effect is quite small, about 70 km/s per megaparsec.

Sowill be moving away from each other at more then the speed of light., yes, two points sufficiently far apart

Originally Posted by sculptor

Is space itself still expanding at the speed of light?

Ok as far as I understand it, expansion is about the distance between the coordinates getting larger. It's difficult to relate that to speed as it's less about movement and more about creating more space. Now the rate of the expansion of space tells us that the universe is approx, 6 times the distance, in diameter, that something could have travelled, travelling at C for the current age of the universe. Markus or Speed can explain far better than I.