How can galaxies recede faster than the speed of light?
by 
keithold thanks all baggers
ANSWERS: 1
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Relativity doesn't mean you can't have speeds that are faster than light. For example, imagine a lighthouse with a laser sweeping round once a second. One mile from the light house the light beam appears to move round at six miles a second. 200,000 miles out and the beam appears to move round faster than light. If you see in the distance two spaceships that start together and then each space ship moves away from the other at 80% light speed, then the relative speed between the ships as measured by you is 160% of light (even though each ship only sees the other moving at 97.5% of light speed). The further away a galaxy is, the faster it appears to be moving away from us. A galaxy that is far enough away becomes invisible as it is receding faster than the light which is leaving it. You can also think of it as the space between us and the galaxy is expanding, so the amount of space the light has to cover is increasing faster than the light can cover it.
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