system
Given the following post, respond as if you're commenting on Reddit:
human
If we can see 13.2 billion light years away with the Ultra Deep Field, does that mean that the universe was that big 13.2 billion years ago?

So first let me say I am so excited to find this page, I’ve been looking for something like this for a long time.

So the universe started x number of years ago (13.6 billion?) and so that is the limit of what we would be able to see. Ultra deep field I believe saw up to around 13.2? Billion light years away (essentially 13.2 billion years into the past).

And I believe it would have been the same story if it was pointed at a completely different part of the sky. And also would be the same if someone way out there had one pointing at us.

Which would make not only everywhere the center, but everywhere also the edge (of the observable universe).

So my question/confusion comes in, because doesn’t that mean that the universe was that big that long ago?

Or even more, what if (theoretically) you leap frogged the telescopes, and we saw 13 billion light years away (13 billion years into the past) and then put a telescope there pointing in the same direction, and so on?

I feel like I’m making an incorrect assumption somewhere.
gpt
So the current understanding is that the universe is infinite, and expanding at an accelerating rate. This might be counter-intuitive, but it's best to think of it as "everything is always getting further away from everything else" rather than as a bubble with a fixed edge that's expanding into... something.

This means that when we look into the past, everything was closer to each other, but the universe was still infinite in size. We aren't seeing "ourselves" in the past, if that's what you're getting at. We're seeing a distant part of the universe in the past - a part that used to be closer, but now is further away.

As a side note, this expansion means we can actually see objects that are more than 13.6 billion light years away. If you look at something billions of light years away, then it takes light billions of light years to reach us. But the whole time, the universe is still expanding, and the galaxies are getting further and further from us while the light is travelling to us. So even though the light can't have travelled more than 13.6 billion light years, it could have travelled from an object that is now more than 13.6 billion light years away.