How are we able to know how extremely far galaxies look like? Shouldn’t they be completely covered/invisible because of the huge amount of celestial bodies that are closer to us?

Question

After a certain distance, won’t all the celebrities bodies create some sort of wall where we can’t see further?

In: 0

Answer 1

No. Space is too empty, and the Universe is too small, for that to happen. Almost all lines of sight into space don’t encounter anything until they reach the [cosmic microwave background](https://en.wikipedia.org/wiki/CMBR), at a distance corresponding to a time about 370,000 years after the Big Bang. At that time, the Universe *was* dense enough that light couldn’t travel freely, so that’s where lines of sight end (at least if you’re looking at light, rather than things like gravitational waves).