Question About The 'edge' Of The Universe.

[Mintaka]

It's my first post here, thanks for making such a great forum and site.

 

I've seen photos on the Hubble site which claim to be of "the furthest visible objects in the universe", clumps of primitive matter whirling around freshly made from the big bang, which hasn't even formed into stars yet.

 

The theory goes ( or seems to a layman like me) that what scientists are saying is that this is looking right in towards the big bang itself, not long after it happened.

 

My question is this:

 

If we could ( in theory) place Hubble on one of these furthest objects, at the limits of our observable universe, and point it in the same direction, what would Hubble see?

 

Would Hubble be looking out into a so-called "void", an empty place devoid of stars because none had formed yet? Or would, in fact, Hubble just see pretty much the same view that he sees now as he orbits our earth......just a further extension of billions of light years of space and countless more galaxies stretching out before him.

 

 

My question is a bit loaded, because i suppose the real heart of it is.....Are we kidding ourselves that these 'unformed clumps of gases and matter' at the limits of Hubble's vision are in fact evidence of the big bang and the beginning of time? Could it just be that these objects are simply as far as Hubble can see?

 

 

To kill two birds with one stone, I'll extend the question:

 

I can't get my head around the idea of there being an 'edge' or 'end'. Somehow mind-blowing infinity seems more believable.

 

After all, when you reach an 'edge' or 'boundary' of something, isn't there always a 'further place' beyond it?

 

Isn't it absurd to think of something outside which there is 'nothing'?

 

Isnt the idea of 'nothing' offensive to a scientific mind?

 

Therefore isn't the word "Singularity" a copout almost on the scale of the idea of "God".

[Tormod]

It seems you are asking about multiple things, so I'll try to give my POV briefly.

 

1. Nothing as absurd to the scientific mind

This is a strange thing to say. The idea of "nothing" is very much a scientific concept.

 

2. Edge of the universe

There would be several types of "edges" to a universe. A physical edge would imply that the universe is finite, there are however various possible shapes of the universe, some of which would give infinite universes yet still keep an "edge".

 

Another edge is the temporal edge, where the universe can be said to have a defined beginning and end. The big bang theory tries to explain what we observe, and as such defines one extreme end of the existence of our universe (the birth). Since it is a scientific theory it cannot be proven correct, especially since we (as of yet) only have a sample of 1 - our own universe. We can only test it by making assumptions about what we would see if so and so had happened, and then make observations, and much of what has been observed matches the expected results. Not everything fits, of course, therefore the theory is challenged.

 

When it comes to the end of the universe, it is difficult to say what will happen. The end result will very much depend of what the beginning was like. We could be living in an endless cycle of universes without knowing it - so this is very much a hypothetical question and much harder to answer than what was before the universe (simply because we know that we do live in a universe, so it must exist).

 

3. What would Hubble see if Hubble was located at the furthest point it can observe

This then becomes an impossibility. What Hubble sees is a view of something that happened more than 13 billion years ago. It did not happen "elsewhere", but in our own universe in the early years. The size of the universe then was much smaller than it is now, but the universe expanded and therefore we can't really say that there was a "middle" or a "given place" where these clouds existed. They were all over the universe.

 

Our universe appears to be isotropic, meaning that it looks the same in all directions because matter is spread equally around.

 

To that we can add that it will also look similar through all ages, in other words at any given time you will see the same from all points of view. So as the universe expands and grows, the view changes but it will still look the same whether you are at point A or B in space. However, if you go from A to B in *time*, things will look different because the universe has evolved.

 

This is why Hubble sees things looking very different when we look very far out into the universe, because we in effect look backwards in time. Note however that it looks the same regardless of which direction we look - so we see the primordial matter in all directions, even though the universe at that time was much, much smaller than it is today. That's a tough one to wrap our minds around.

 

So Hubble would see what it could see at that time - a lot of plasma clouds, and not much else. The background radiation would be much higher than today, and the universe would appear much smaller (but there would be no yardstick against which to measure it).

 

4. Is the singularity a copout or a religious view

The assumed singularity at the beginning of time is a natural result of what happens when we take our observations and run them backwards. Everything appears to come out of a gravitational singularity. The cosmological problem is of course to explain what *really* happened. There have been several attempts. The religious view does away with all attempts and thus is not scientific. The scientific view is to figure out possible ways to explain it and then test it. There are many explanations to date, such as string theory which predicts (basically) that there was no singularity at all, and that time did exist before the big bang.

 

5. Isn't there always something further beyond

This is circular logic. Beyond what? And what is the "something" if it is not part of our universe? When a baby is born, it becomes a single entity. Yes, there is something "further beyond" - there are parents. There may be siblings. There may be offspring one day. But the baby's existence can be explained on it's own terms. The fact that we don't understand how the universe came to exist does not require us to assume that it is part of something bigger.

[HydrogenBond]

If we assume a big bang, regardless of the type of expansion, it goes from smaller to bigger. If we assume it is still expanding, there is a volume of space and time, that the universe will occupy tomorrow, that the universe does not occupy today.

 

If you look at a blackhole, although space-time is higher contracted at the blackhole, all the way to the limit, the space-time impact decays with distance from the blackhole. Since the mass/energy of the BB was finite, one would expect that even its space-time impact would decay in the context of infinite space. If we were to expand a blackhole, the space-time in the center of the blackhole will expand, however, since mass is moving outward it can contract space-time in areas where the original space-time was very decayed. In other words, if a light year away there was negligible impact from the original blackhole, but all of a sudden a chunk of mass reaches that point, space-time contracts more.

 

Relative to the universe, from the original center space-time expands, as matter moves outward. It moves toward where the original space-time impact of the BB was decayed. At this leading edge, space-time is contracting relative to its original state. Where the universe will be tomorrow is where the space-time is contracting. Ironically, the galaxies and stars are contracting space-time as gases and dust get denser and denser. This is may be one edge.

[Mintaka]

Thanks for such exhaustive replies, I can't say I understood all of it, but laymen tend to be good at posing questions which they probably won't understand the answers to..

 

Do philosophers have any part to play in these discussions? Do scientists and astronomers take into account what the philosophers say on the subject of the universe, or is it now really something that can only be understood by people with a higher education in astrophysics or astronomy? Is it possible some great illuminating insight could come from some humble eccentric smoking dope out on the plains of Nebraska with his feet up on his balcony?

 

Last night I saw, for the first time, and with amazement, a red star. I was looking towards Orion with a simple pair of 8 x 32 binoculars and was looking for Beltegeuse, having read that it is a red Supergiant. But to actually see it glowing red was mind-blowing to me. Today I read that in fact this star which is over 800 million km in diameter, could actually already have exploded.

 

I suppose with wonder and curiosity we'll get there in the end, wherever 'there' is.

 

Thanks again..

[Tormod]

Do philosophers have any part to play in these discussions? Do scientists and astronomers take into account what the philosophers say on the subject of the universe, or is it now really something that can only be understood by people with a higher education in astrophysics or astronomy? Is it possible some great illuminating insight could come from some humble eccentric smoking dope out on the plains of Nebraska with his feet up on his balcony?

 

The questions you ask are philosophical in nature and as such relates nicely to cosmology, the study of the universe and our place in it. Cosmology is a nice mix of philosophy and natural science.

 

But it depends on what and who you're asking. What exactly should astronomers take into account? Our current scientific understanding of the universe comes from the ability to look beyond philosophy and study hard facts - but if nobody had asked "why" in the first place, there would not be anything to study. Great thoughts bring great discoveries, which again inspire great ideas.

 

I'm not a scientist myself, so I can't pretend to be talking on behalf on one.

[freeztar]

Those are some very good questions, Mintaka.

 

I think that if we could instantly place Hubble at the "edge" of the universe, that it wouldn't see much. It's tuned to gather light from distant galaxies and the light coming from the beginnings of the universe would most likely be blinding to the poor Hubble.

 

Also, if we could magically place it there right "now", it would see probably a similar view to what we see from our point in space and time. For the light that we see from the "edge" of space right now is not only far away in distance, it is also far away in time - about 13 billion years before the present time.

 

There is no real "edge" to the universe. Or rather, it would be impossible to ever reach one as everything that can be considered "the universe" has photons beaming in every direction at the speed of light. Since light speed travel is impossible for atomic bundles such as ourselves, it will forever be a place we can never go.

[Vox]

It's my first post here, thanks for making such a great forum and site.

 

I've seen photos on the Hubble site which claim to be of "the furthest visible objects in the universe", clumps of primitive matter whirling around freshly made from the big bang, which hasn't even formed into stars yet.

 

The theory goes ( or seems to a layman like me) that what scientists are saying is that this is looking right in towards the big bang itself, not long after it happened.

 

My question is this:

 

If we could ( in theory) place Hubble on one of these furthest objects, at the limits of our observable universe, and point it in the same direction, what would Hubble see?

 

Would Hubble be looking out into a so-called "void", an empty place devoid of stars because none had formed yet? Or would, in fact, Hubble just see pretty much the same view that he sees now as he orbits our earth......just a further extension of billions of light years of space and countless more galaxies stretching out before him.

 

 

My question is a bit loaded, because i suppose the real heart of it is.....Are we kidding ourselves that these 'unformed clumps of gases and matter' at the limits of Hubble's vision are in fact evidence of the big bang and the beginning of time? Could it just be that these objects are simply as far as Hubble can see?

 

 

To kill two birds with one stone, I'll extend the question:

 

I can't get my head around the idea of there being an 'edge' or 'end'. Somehow mind-blowing infinity seems more believable.

 

After all, when you reach an 'edge' or 'boundary' of something, isn't there always a 'further place' beyond it?

 

Isn't it absurd to think of something outside which there is 'nothing'?

 

Isnt the idea of 'nothing' offensive to a scientific mind?

 

Therefore isn't the word "Singularity" a copout almost on the scale of the idea of "God".

 

Sir Roger Penrose Christmas lecture

 

http://www.youtube.com/watch?v=OutKE3tyG94

[36grit]

I think my latest post on this site explains the edge and answers a lot of questions.

 

It took me a while to get this one down

 

http://scienceforums.com/topic/22878-infinite-theory/

[HydrogenBond]

If we assume infinite space, then there would be an edge to a finite universe. As an analogy, say we had a blackhole. It bends space-time to a singularity in its center. But since it is finite in substance, the space-time impact of the blackhole decays quickly with distance. The black hole on the center of our galaxy was inferred from its local impact and not directly by its impact on earth, since its practical impact is too decayed to measure on earth.

 

If we could expand the blackhole somehow, the blackhole would see its local space-time expand, but here on earth we may not notice anything different other than the distant observations of the blackhole would alter as its localized space-time expands.

 

If we assume a finite universe in infinite space, we would get the same type of effect. Far enough away the finite singularity of the BB would decay its impact, even though locally space-time could be highly contracted. The math may say its impact extends all the way to infinity, but in practical terms, its impact within infinite space would eventually get so small, other local effects, even the tiniest would be the more dominant effects. The edge would be where the impact on infinite space is so small it has no practical impact.

 

Maybe we could use a blackhole to generate a calculation, then extrapolate that to our finite universe. Where is the edge of a blackhole in terms of where the sum of other effects makes its decaying impact a non-event. We tend to assume our finite universe is the only thing, which will bias our POV. It would be like the blackhole saying, I am the universe and them assuming where its own practical effect stops that is also where the universe has to stop.

[borgius]

(My) motto: Instead of trying to squeeze the Universe into your mind, expand your mind into the Universe." (www.chess22.com)

 

Anyone believing that the Universe can be explained by the limited human brain is kidding him/herself... and, huge egos make clear vision impossible.

 

"Edge of the Universe"... "Big Bang"... "13 billion years ago", etc... Extremely shallow thinking!

How about "no beginning, and no end"? Galaxies were forming 26, 52, 104, 208 billion years ago, and even 999,999,999,999,999 x 999,999,999,999,999 billion years ago, and so on. So don't even question what Hubble would have seen.

 

"Infinity sounds more acceptable..." reads one of the posts. Indeed, much more acceptable than senseless speculations.