What exists beyond the known universe?

[Tormod]

Originally posted by: Freethinker

Originally posted by: BlameTheEx

light does not have a temperature, but is colored by it."

 

The "color" of light is based on the TEMPERATURE of the black body radiator producing it. Light IS measured by "color temperature".

 

 

For the record...that is my quote you're replying to, not BEX's.

[BlameTheEx]

Freethinker

 

I considered replying to your last message, but lets face it, life's too short already.

 

Tell you what. If you can shorten it a bit, and rephrase your points into a more polite style (one of which, at least, is a good one) I will give it my best shot. But at the moment your not coming over as nice enough to waste the time on.

[BlameTheEx]

Alll

 

My conscience is bothering me.

 

However impolitely, Freethinker did come up with one fair point. extremely red shifted galaxies won't work as a direct source of the 3K background radiation. If it were the case, we would expect more radiation from rather less red shifted galaxies.

[paultrr]

One thing that must be remembered here is not only does red shifting effect the amount of light we can receive, but, also, the speed of light and the age of the universe along with its actual size effects this. If the universe is some 14.5 billion years old and if C has remained constant since the end of the inflation period we can only expect to see light from that many years away. The speed of light sets its own limits on what we can observe. Also, as we look out into space we are also looking backwards in time, not forwards in time. The universe by some estlimates is some 75 billion light years in radius. These are assumptions even if they are based upon some knowns at present and as such are subject to a lot of possible errors. But, if the universe is that big then we only can expect to see only a small portion of that universe at anyone time. Its expansion also plays into this effect. In general if the current evidence for an accelerated expansion holds true what we can actually view will get less and less with time. Its expansion rate would eventually far outrun the velocity of light. Add into that some of the speculation that C may slow down with time and the case gets worse.

 

Part of inflation theory makes the prediction that the early universe expanded by some 10^50th powers. Even at that stage if one assumed C had its current value the whole universe has never been viewable from the inside.

[Tormod]

Originally posted by: paultrr

Part of inflation theory makes the prediction that the early universe expanded by some 10^50th powers. Even at that stage if one assumed C had its current value the whole universe has never been viewable from the inside.

 

A very good point. For some reason we still need to hammer into folks that the big bang theory does not result in the universe having a center. But a lot of people also struggle with inflation and expansion and ask questions like "what does the universe expand into". I discussed this with a cosmologist at the University of Oslo a few years back when I worked as a science reporter and he explained that the problem is basically that people tend to think of the universe as the inside of a balloon, whereas it is much more practical to think about the observable universe as a circle on the surface of the balloon.

 

It means that even though we can only see as far as the curve of the balloon allows, we will be able to see farther as the balloon expands. But the expansion of the balloon as a whole will happen at a different rate than the expansion of the surface. Outside of the visible universe is simply more universe. Outside that - there is nothing, and there is nothing "above" or "below" either. But since we cannot observe it we cannot ever prove it (which was also a point made by John Barrow in his book "Impossibility" [aka "Pie in the Sky"]).

[paultrr]

If the Universe expands into anything under current thinking that something would be hyperspace itself. However, the modeling here on that subject itself differs across the board. The original idea way back was the universe was all there was. More recent modeling throws in the idea of hyperspace. But then again, to a certain extent hyperspace is also looked at under String Theory as the internal compacted space-time. Then you have hyperspace with multiple universes, sometimes refered to as the multiverse.

 

As far as our own perspective goes there is no center. I grant, from the aspect of a space-time or universe evolving from a singularity there should be something of a center to that expansion even if that center is never viewable by any means. We also through out terms like Hawking does about space-time being finite and unbounded. Simply put this means that the universe while finite in size has no outer edge, per say. The terms we use in themselves tend to get confusing.

 

About the only thing we do seem to know is that the universe from what we can tell observationally has no center, we cannot see any real boundary to it, and if there is such a boundary out there someplace that boundary is ever expanding at the present and for lack of a better word if it does expand into something the best discription we have at present is to call that other space hyperspace. What the real properties of that hyperspace are at the present can only be guessed at with theory. Here almost all of us who study cosmology and physics have our own view. But good point. Those are questions that keep getting asked inspite of all the decent popular science books and articles out there on the subject.

[pgrmdave]

why does there need to be anything beyond the universe? If it can't affect us and we can't affect it, how do we know that there's anything there? All the mental exercises have a basis in our own understanding of our universe and so they are inherently flawed to judge properties of a "beyond".

[Tormod]

why does there need to be anything beyond the universe? If it can't affect us and we can't affect it, how do we know that there's anything there? All the mental exercises have a basis in our own understanding of our universe and so they are inherently flawed to judge properties of a "beyond".

 

Yes. I think that is what both I and paultrr are saying.

[BlameTheEx]

pgrmdave

 

One thing we do know with fair certainty. About 14 billion years ago the universe, as we know it, started. We don't know if that is the age of the universe itself, but there is just too much evidence that the contents of the universe are about that age.

 

Where did the contents come from? Perhaps they were always here. A cyclic universe which explodes, expands, and then contracts back to a point again. Perhaps there is another explanation that requires no external influence. However, the evidence IS coming in to eliminate possibilities. A time may soon come when we can say with confidence that the universe could not have started without external influence. If that day happens, we will have proof that there is something outside our universe.

 

If our universe was affected once by something external, there is a very good chance that it is still being affected. That means that we can study the nature of the "beyond" by studying its affects. In principle, we should be able to affect it in return. Communication is thus possible.

 

There is a big difference between something that is possible in principle, and something that is possible in practice. Maybe our dimensions of space, or even time, are local to our universe. If so our universe can interact externally only as a point source as far as our perceptions are concerned. It may have a position, or even features within other dimensions, but they will be of little help to us. We will only be able to affect the "beyond" by affection our universe in general. To make a significant change to our universe throughout space and perhaps time too will be forever beyond us.

[Aki]

I think our universe is a closed system, meaning that nothing from the outside can affect the universe. According to the string theory, many universes are aligned parallely, like loafs of bread. So my guess is there are infinite number of universes outside ours. But really, at the moment and in the near future, no one can possibly have a definite answer to that question.

[paultrr]

As for that which is outside(hyperspace) effecting us inside take this into consideration: One aspect of all the multidimensional ideas out there is that gravity is only weak because it leaks off this brane. In hyperspace gravity by theory should be stronger. That implies that our forces of nature are the way the are because of external differences. So even in modern theory it is possible what is external has influence on us. The real solid difference here with the idea of an external God is that it is nature itself via its own higher dimensions that provides the first cause. Not some outdated faith based version of a creator.

[Aki]

To add on to paultrr, it is mentioned that the only way to communicate with other universe might be through gravity, since it is believed gravity escapes to other dimensions and to other branes.

[adamntm]

well im new hear, and im not so sure about aki's last post. but ne ways to respond to the original post. Ive also done some thinking about this topic as well, and i thought that if there were to be, some type of wall or boundary to this universe, wouldent that be implying that theres something beyond it. hmm thats a biiig statement to start thinking of something like that. i always thought that a 'space' was just a place where something with the same general properties could exist. i mean, hey, if our universe were to be infinite in all directions wouldent that be a kind of boundary? sense we base our thought on expirience we cannot no what we dont expirience and therefore anything outside of this universe is unknown. like what freethinker said ealier and hes entirely right. and as for demensions, well who says there is any demensions, and just because they say there is doesnt mean there right, i mean, how distant does space become if theres nothing inside of it. P.S. dont believe a thing paultrr says, he doesnt no what hes talking about and hes claiming its all true.

[adamntm]

Actually, every thong I've ever seen is almost nothing.

 

 

ahahahahahaahahaahahahahaha

[Tormod]

i thought that if there were to be, some type of wall or boundary to this universe, wouldent that be implying that theres something beyond it.

 

Some good thoughts, adamntm. Just a friendly tip: It would help the readibiliy if you could break up the paragraph a bit. ;)

 

We don't know if the universe has a boundary. We do know that it does not have a center (at least according to current theories). The second seems to rule out the former, but it would depend on how many dimensions the universe really has, and how space-time is curved. If you read through the thread there should be some answers, but this is a rather circular-logic kind of topic which is hard to fathom.

[pgrmdave]

We do know that it does not have a center (at least according to current theories). The second seems to rule out the former, but it would depend on how many dimensions the universe really has, and how space-time is curved.

 

Couldn't the universe be finite but have no boundries? Like the earth, you can move along its surface infinitly, but it is a finite plane.

[Tormod]

Yes, indeed. That is one of the most plausible explanations.