Space also is cold.
Logical conclusion, space is transparent,
therefore it doesn't absorbs much light ( head and energy),
therefore it is colder.
Space is deep and
just the background is dark.
The light takes a long time to travel so it is not really visible to us.
13.7 Billion ligthyears of deepness is much.
Due do the fact space is filled with heat absorbing and radiating Objects and that
space still absorbs a little heat, it continuously expands. So space get's even darker. ^^