# Is it possible to see the history of space if it expands faster than light?

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• ramim
In summary, if you were to stand at the edge of the universe as it expanded faster than the speed of light, you would see all the light from the galaxies that has already traveled to you. You would also be able to see the formation of the universe. However, there is a limit to how far back in time you can see.
ramim
TL;DR Summary
Can we view the history of space from the edge of expansion as it was expanding faster than the speed of light?
I was wondering if it would be possible to see the history of space if one was to stand at the edge of the universe as it expanded faster than the speed of light. If the universe was to be expanding faster than the speed of light right now, and I was able to somehow go there and keep up with it, what would I see if I turned around? I have thought about this and I was wondering if you would be able to see the history of the universe. Since the universe would be moving faster than the speed of light, all the light traveling to the edge of the universe would lag behind it and thus if you turned around and stopped, eventually all of that light would reach you. So what exactly would you see? Would you just see light from galaxies, etc., or would you be able to see the the formation of the universe?
This also leads me into a side question. Since the universe is not expanding at the speed of light, what happens to the light that reaches the edge of space? Does it just move at the speed of the universe expansion? If that is the case, this is why I reached the conclusion above (that you can see the formation of the universe). If the Big Bang is true then as the universe started expanding, that light being emitted is just following the edge and so you would see it if you were at the edge.
Have I made a mistake in my thinking or is this certainly true?

ramim said:
If the Big Bang is true then as the universe started expanding, that light being emitted is just following the edge and so you would see it if you were at the edge.
Have I made a mistake in my thinking or is this certainly true?
There is no edge (and the Big Bang didn’t happen at the center either). Many previous threads here explaining this...

A fundamental principle of our understanding of cosmology is that, on large scales, everything is the same everywhere. So an observer in a galaxy at the very edge of what we can see would see everything around him/her/it looking much the same as it looks here (as Nugatory notes, there's no edge to the universe - but the finite speed of light limits how far we can see to how far light can have traveled since the beginning of the universe). There would be different stars and galaxies, of course, but they would be just stars and galaxies like we see around us here.

ramim said:
Would you just see light from galaxies, etc., or would you be able to see the the formation of the universe?
If you could see far enough, assuming our models of the universe are correct then you could indeed see back to events arbitrarily close to the formation of the universe, yes. The farther away you look, the farther back in time(1) are the things you see.

However, there is a limit to how far away/back in time you can look. If you look back to around 400,000 years after the big bang, you see the surface of last scattering -- this is where the cosmic microwave background radiation comes from. Prior to this time, the universe was opaque to visible light. So you cannot see past this point using visible light (which, due to cosmological red shift now manifests as microwaves in your radio dish).

(1) Here I am implicitly using standard "co-moving" coordinates to establish a standard of cosmological time.

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ramim said:
... or would you be able to see the the formation of the universe?
In addition to what @jbriggs444 already said astronomers could in principle detect gravitational waves produced during inflation, the super-fast expansion almost at the beginning of the universe.

## 1. Can we see the history of space if it expands faster than light?

No, it is not possible to see the history of space if it expands faster than light. According to the theory of relativity, nothing can travel faster than the speed of light, including light itself. Therefore, any objects or events beyond the observable universe cannot be seen.

## 2. How does the expansion of space affect our ability to see the history of the universe?

The expansion of space does not directly affect our ability to see the history of the universe. It is the speed of light and the distance of objects that limit our ability to see the past. As space expands, objects move further away from us, making it harder to see them and their history.

## 3. Is the expansion of space faster than the speed of light?

Yes, the expansion of space is faster than the speed of light. This is due to the fact that the expansion of space is not limited by the speed of light, as it is not an object moving through space but rather the space itself expanding.

## 4. Can we ever catch up to objects that are moving away from us due to the expansion of space?

No, we cannot catch up to objects that are moving away from us due to the expansion of space. As the space between us and the object expands, the distance between us also increases. This means that the object will continue to move away from us at an increasing rate, making it impossible for us to catch up.

## 5. How does the expansion of space affect the age of the universe?

The expansion of space does not affect the age of the universe. The age of the universe is determined by the time that has passed since the Big Bang, which is estimated to be around 13.8 billion years. However, the expansion of space does affect our ability to see the history of the universe, as it makes it harder for us to see objects and events that are further away.

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