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First I'll explain the background of my question. With the use of telescopes and other systems we can look at objects that are very far away, far enough away so that we can see how they were in the past. This is because we are observing the light that is traveling to us, so things that are many light years away will take years to reach our vision. We have observed events in space such as a supernova that occurred hundreds of thousands of years ago and we have also devised machinery to look into the very beginnings of the galaxy. The Wilkinson Microwave Anisotropy Probe was a project by NASA where they took temperature driven pictures of the universe 13 some odd billion years ago. My question is this.
If we had the technology to look far enough away to the time before the galaxy was created, what would we see?
I was wondering about this earlier today and I haven't the knowledge to answer it. I have some ideas but I'll wait to post them, just in case the answer is really simple and I'm just asking silly questions.
And a Very difficult or at least open ended one at that.
I would also like to add to it, "What direction should we point our new look back device?" (telescope or whatever)
I don't personally buy into the Big Bang, though, so I am more comfortable with the notion of not ever being able to know the "beginning" point or even if that concept can be applied to the Universe. We see things go through cycles and so we have come to assign a beginning to an arbitrary, if somehow significant, point of the cycle and believe that we have proclaimed a truism. I think that this way of thinking is merely myopic (short sighted--being too close to it).
If there were a single big bang, we should be able to determine in which direction is was oriented and then be able to look both back to it and out away from it. Don't you think?
And a Very difficult or at least open ended one at that.
I would also like to add to it, "What direction should we point our new look back device?" (telescope or whatever)
I don't personally buy into the Big Bang, though, so I am more comfortable with the notion of not ever being able to know the "beginning" point or even if that concept can be applied to the Universe. We see things go through cycles and so we have come to assign a beginning to an arbitrary, if somehow significant, point of the cycle and believe that we have proclaimed a truism. I think that this way of thinking is merely myopic (short sighted--being too close to it).
If there were a single big bang, we should be able to determine in which direction is was oriented and then be able to look both back to it and out away from it. Don't you think?
Regards, Aaron (My middle name)
I don't blame you for not buying the "big bang" as you describe it, but that's simply because you have a rather confused idea as to what the actual theory is.
Firstly, the big bang model, or if you want to be more precise the standard LCDM model of cosmology, states that the universe is both isotropic and homogeneous; that is, that there is no preferred place, and no preferred direction in the universe. Thus, the big bang theory did not say that there is one point in space from which the universe exploded, nor that there is one direction from which the bang was oriented. A concise definition of the big bang model would be something like "the universe was, at one time in the past, a lot smaller, and more dense than it is today."
So, back to the original question. Yes, it is indeed true that as we look further into the distance, we also look further back in time. However, I'm not exactly sure what your question is. Do you mean what would we see if we were able to look back far enough to a region in time when a certain galaxy has not formed, or do you seem to think that we could look back to when our own galaxy has not yet been formed? It sound like you are asking the latter, which cannot be true, since in looking into the sky we are not doing anything magical to our local region of spacetime.
~neutralino
If you haven't found something strange during the day, it hasn't been much of a day - John A. Wheeler.
Well I guess the question would be what would we see if we looked over 13.7billion light years away.. or however old the universe is. Could we see a point before the universe was formed, and if we couldn't what would stop us from seeing into that distance?
Just wondering if we can see into something that doesn't exist yet, and if not what would the edge of what is real and what is not yet real look like or be like?
Sorry neutralino I meant universe not galaxy.
So what would the outside of the universe(red circle) be like? The cross from reality to the time before reality is marked by the yellow poof thing. I get that their would be no light outside and we would probably see nothing, or is it impossible to see things far enough away in light years to see before the universe started? I guess that the outsides of the universe would have to travel faster than the speed of light for this to be possible.. or maybe I'm asking silly questions
It's just that we can look back so far.. but can we look to a point before everything started?
Well I guess the question would be what would we see if we looked over 13.7billion light years away.. or however old the universe is. Could we see a point before the universe was formed, and if we couldn't what would stop us from seeing into that distance?
We can certainly, in principle, look further than a distance of 13.7 billion light years, even if the universe is 13.7 billion years old, since that bound on the size is only valid for flat space. However we cannot, even in principle, look to a distance greater than the size of the (observable) universe, simply by definition. To see something we need photons to be transmitted from the object to our telescope. Thus we can only see something if there was enough time for the photons to travel the distance between us and the object. The horizon of the observable universe gives us a bound on this.
There are also other problems like the fact that photons must be decoupled and free to be emitted in order for us to have any chance of seeing anything from that specific time. This hasn't always been the case, and in fact the very early universe was opaque, since photons were bound to the matter. The first epoch where the two decouple is sometimes called last scattering, or more commonly known as the time when the Cosmic Microwave Background radiation was produced. Anyway, this is the topic for another thread!
Well, I hope I've answered your question, I doubt it though, but I tried!
~neutralino
If you haven't found something strange during the day, it hasn't been much of a day - John A. Wheeler.
Last edited by neutralino : 04-15-2008 at 04:13 AM.
Reason: potentially confusing comment
I understand that we wouldn't see anything in the space of nothing, I was wondering about the contrast between the edge of the universe and the nothing after it. What is something that we cannot see? Is it a giant wall, or a street leading to a dead end sign, leaving you saying.. "well, this is the end."
I just thought the concept of the edge of reality was nifty, and being able to see back in time got me wondering. When I think about it more I don't think that their can be an end, but that could just be my mind applying something infinite to explain what I can't.
If we were both on the very edge of the universe, separated by one foot from the universe to the nothing outside of it. What would stop us from moving crossed that line?
I think that the universe would continue to create more space, never allowing us to reach an end, which is all just a feeling and nothing else. Maybe I'm using those infinites again!
It seems you are confusing the notion of universe with that of observable universe. This isn't surprising, since I think most cosmologists uses the former term when sometimes they mean the latter, and vice versa (and I'm sure I've been guilty of doing so above!) To clarify, the observable universe is everything we can possibly observe today; it is a finite subset of space, and is usually thought of as a sphere centred on ourselves. Now, there is no reason to think that the observable universe is the entire universe. In fact, if it were, then it would be pretty weird since we would be sat at the centre of the universe (disobeying the cosmological principle). Thus, the entire universe is a lot bigger than the observable universe and could even be infinite (so there's nothing wrong with your use of infinity!)
However, the important thing to notice is that every point in space has its own observable universe at each point in time; a finite sphere centred on that point. Thus, the event horizon at the "edge" of each observable universe is not a physical boundary in the sense that we walk up to it and encounter a wall, it is simply a boundary past which we cannot see from the centre of the observable universe.
Again, I hope that makes sense. Also, note that I corrected a sentence in my previous post regarding boundaries as it was potentially misleading.
~neutralino
If you haven't found something strange during the day, it hasn't been much of a day - John A. Wheeler.
Thanks neutralino I think I get what your saying. It seems that with that the universe would be infinite, as you could keep moving along the circles of the observable universe.
Yes, one option is that the universe is infinite, however that picture does not rule out the possibility of the universe being finite-- the universe could have positive curvature and be closed. To picture this, let's throw away one dimension of space and imagine living on the surface of a sphere (so we don't see the third dimension in the radial direction of the sphere). In this case, we can continue the diagram you have in your last post ad infinitum without hitting any boundary, but the space is not infinite in its extent. To come back to "real life" the topology of the actual universe could then be equivalent to that of the 3-dimensional surface of a 4-d sphere (something that we can't really imagine!)
~neutralino
If you haven't found something strange during the day, it hasn't been much of a day - John A. Wheeler.
Linear Mode
