Quote:
Originally Posted by AnotherCat
For those interested with an open mind and not just wanting to be argumentative  I came across this explaining the Ant on a rubber rope paradox.
It explains how if an ant walks along a rubber rope that is expanding in length at a constant rate faster than the ant is walking, the ant will still reach the other end because the mathematical series that describes the ants progress does not converge. So it shows how something travelling towards one at a speed less than the expansion of the medium it is travelling along will eventually reach one even in our own local flat world.
It goes on to briefly use this example to put into intuitive terms why light from galaxies travelling away from us faster than the speed of light will still reach us - I am not sure this takes into account of the less intuitive parts of general relativity, but the effect lives.
It points out that the universe's expansion is believed to be actually accelerating (and the actual rate seems to be up for grabs at the moment) and so that places a limit on the visibility of the furthermost of those "faster than the speed of light" galaxies but those within that limit will be visible (and are, their red-shifts have been measured). |
The light that reaches us was emitted by the galaxy before it reached the threshold. The light it emits after crossing the threshold will never reach us because the intervening space is expanding by more than a light year per year. In no case is any of the galaxies moving at anywhere near light speed.