Originally posted by Asylum-Fry:
Is it true that if the universe were to stop expanding, then space would become white instead of black?
Just out of curiosity and all...
Here is a little something that I found on the web, This is my understanding of the situation:
In a universe of infinite age and size, every line of sight should end in a star, so why is the night sky largely dark? Assuming a similar average density of stars throughout the universe, then the number of stars in a particular direction increases proportional to distance away. However, the intensity of light from distant stars diminishes proportional to the SQUARE of distance away. Therefore the total average light from any particular direction is inversely proportional to the distance of the nearest star, so some/most directions will appear dark.
Now note, the Universe is neither infinite in size nor age. But, given enough time, there would be enough stars to fill in the gaps. You would end up with a night sky that looked either like the Milkyway looks at night to a continuous haze of white.
But, since the Universe is expanding, everything gets farther apart before the light can build up, and we get out dark sky. If the universe starts to shrink, the reverse would happen (the sky would get lighter and lighter with time).
Hope that helps. I'm sure there is a physicist somewhere lurking that can expand on this.