How far back in time can we see?

Question

When we look at the sky we are looking back in time. How far back can we see? Does it depend on optics? Is it practically, or theoretically possible to see the big bang? Is there a place in the sky where we think the big bang might have originated?
Thanks in advance!

Answer 1

Once again everyone seems to have missed. The Cosmic Microwave Background is not a remnant of the big bang it is the radiation that resulted from atoms (proton+electron) combining for the first time. This occurred about 300 000 years after the big bang and this is as far back as we can see (around 13 billion years). Before that time the universe was an optically thick "soup" of particles and light and since light could not escape that "soup" we can't ever see it.
Secondly, and more importantly, if you look up at the sky and write down all the directions of all the galaxies you see and then try and find the point that they are all moving away from you always find that it is you. This is true for every point in the universe. Essentially the big bang happened everywhere, not at some location in the sky. Think of blowing up a balloon from a very small point and then when it's large asking what point on the surface is the centre, they all are. At the big bang every point in the universe was touching and in an infinitely small volume, thus the big bang happened everywhere. Believe me, this is what I do every day.

Answer 2

We can see about 14billion light years back. No, it doesn't depend on optics because it is theoretically not possible to see the Big Bang because of the sub-atomic particle malaise that was going on in the early univers. And no there isn't a place where we think the universe originated because we cant see that far back, and the geometry get distorted when we look very many light years away (of order 10^10 parsecs). Also, how can we say the universe originated in one spot? What would make this place special? The expansion of the univers has no "centre" from which it is expanding outwards from:
Basically because we need to think in four dimensions and not three.

Answer 3

e The farthest galaxies we see do not exist to-day.
Trying to estimates which ones still exist may not be possible
The first stars lit up about 100 million years after the origin.
so it is probably not possible to look beyond the first light that these stars produced.
The red shift may not be a reliable predicator to estimate the distance to remote galaxies or if they actually have a recessional velocity

Answer 4

We can see back to about 300,000 to 500,000 years after the big bang. These are the most distant parts of the universe our telescopes can see, and do not have the usual galaxy formations we see elsewhere.

The background radiation is a remnant of the big bang, but is not looking back in time as such. It is radiation thermalised over time.

Answer 5

Astronomers have observed galaxies 13.7-billion light years from Earth. So far those objects are the most distant we've been able to see. We're seeing those galaxies as they were 13.7-billion years ago so that's how far back in time we can see too.

P.S.
We can *not* see all the way back to the instant of the Big Bang.

Answer 6

There have been two answers saying the Andromeda galaxy is 2.1 light years away. It is not. It is 2.5 MILLION light years away. It was me who gave the two answers thumbs downs to alert people to this misconception.

Answer 7

You can see the Andromeda Galaxy on a clear night. That's around 2.1 light years away.

Answer 8

COBI sees all the way back to the big bang looking at background radiation

Answer 9

We can actually see billions of years back in time. Light from distant galaxies takes millions, even billions of years to reach us.

http://en.wikipedia.org/wiki/Hubble_deep_field

Answer 10

With your naked eye you can see the Andromeda Galaxy on a clear night. That's around 2.1 light years away