Is the Universe Infinite?

The only infinity that has real clout is an infinity of space containing an infinity of matter. No-one here has yet suggested that that exists, so it's a pretty one sided debate so far.

If there is infinite space around a limited physical universe, then at some point it becomes completely flat, unaffected by gravity, and completely cold. Zero degrees K.
Perhaps not nothing, but fairly close to it.

Monton sounds ok.
I like his book title:
Seeking God in Science
An Atheist Defends Intelligent Design

I don't think that an atheist can do that, but I'll resist the temptation to get the book.

 

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I agree, though I only recently came across him and haven't read any of his work. But a quick review of his books and credentials seem to stand up.

There are a few scenarios that cannot be easily refuted about possibilities of a universe with infinite space, infinite time, and finite energy. They don't fit the FLRW mold and they require reasonable and responsible speculation. The definition of reasonable and responsible though is hard to establish. It can't help but become speculation upon speculation and further and further from any acceptable connection to the consensus.

The first requirement to move from what is considered the standard cosmology and to move to an infinite alternative is to speculate about the cause of the Big Bang. BBT doesn't actually address the issue one way or another accept in the math as I pointed out earlier, i.e. the math of BBT starts with a singularity. But even the singularity becomes moot when you move to quantum gravity and particle physics which are going to have to resolve the existing incompatibilities.

But to be fair, since there is no evidence of any condition at t=0 or before, it quickly becomes speculation upon speculation and that is the realm of pseudoscience.

 

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The universe is "Open". The reason for this is while their is sentient life trying to invent new things and plan for a future, there will always be "new" things developed and "brought into the universe". To "box ourselves in" and define the universe as "finite" would be counter productive.

Incidentally my own person view (which some will disagree with, but there is always going to be that) is that the Universe is made from the pinnacle of our sciences (we just haven't reached that pinnacle yet). Every atom is a Tangent Adaptive Node or TAN unit, capable of interconnectivity with other atoms to create molecular structures. This structuring allows for "computation" (not just at a Quibit[Qbit] level), it doesn't require vast powerstations to supply power to keep data stored like RAM with it's Cyclic Redundancy, it doesn't necessarily require vast powerstations to cause it's change of state.

I guess you could say the atom is like the mythical grail, although in this instance it's something that exists, it's tangible and it does what it does and we too this point have only been "reverse engineering" it, rather than perhaps trying to "bridge" the understanding that "what we reverse, we also build".

Logically chaos theory dictates that we could tangent ad-infinitum and never build to the same blueprints, which means generating a finite structure that is made consensus not just on the linear plane that we currently interpret things on but through a multiversal construct. (Using more than one universe to a common goal of building a multistate construct).

It will seem like fiction to most, but I'd love to hear how others that object to it... do so.

 

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This is an interesting concept but we also have determined that the universe was open using observations. An open universe will expand forever but will end badly if it is finite in content. So aren’t we boxed in by GR either way? Maybe you are saying that the universe is not finite in content?

These atoms had to come from somewhere. According to Big Bang Nucleosynthesis we had the development of deuterium and helium nuclei in the first couple of minutes, an ionized gas of free electrons, protons and helium nuclei form around ten thousand years, and then after about 300,000 years we got neutral hydrogen and the emission of photons from the light gases. Are you incorporating this scenario saying that the atom is there because it emerged from the chaos or because we somehow built it before we existed

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It isn’t the standard cosmology

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. I don’t know if “object to it” is what I’m thinking as much as I have questions about how you derive your view. Do you consider the Big Bang to be the beginning or are you viewing a more perpetual universe or one that has always exited and our Big Bang was just one event in a bigger picture?

Can you be more specific about the statements that seem to put some consciousness into the course of events as if “we also build” what we have become a part of?

 

This is actually a technical term, and something that we can test. It has to do with what two parallel light rays will do.

If the universe is flat, then two parallel light rays will always remain parallel. In this case, the universe in infinite.

If the universe is closed, it is not infinite, and two parallel light rays will eventually intersect.

If the universe is open, two parallel light rays will move apart from each other.

The currently accepted cosmological model has a parameter called \(\Omega_{tot}\). This parameter measures the energy density of the universe, compared to some critical density. If \(\Omega > 1\), the universe is closed, if \(\Omega < 1\) the universe is open, and if \(\Omega = 1\) the universe is flat.

The current value for \(\Omega\) is like 1.005, but the margin of error makes a flat universe just as likely.

So the answer to the thread is that it is not known, but can be tested experimentally.

 

Just a thought but, if the universe could be both open and closed at the same time wouldn't we observe it as being flat? In other words, if space were both expanding globally and recollapsing locally wouldn't we observe a flat expanding universe with deviations around localized areas?

I believe it is. You can have an infinite amount of space confined inside a finite amount of space. For example, there are an infinite amount of numbers between 0 & 1 yet we know that 0 through 1 is finite. In the case of the universe, no matter where you are located that is the center of the universe because the visible horizon (thd visible "edge") will always be at a distance relative to the age of your point in space. The only way to "move closer" to the horizin is to stop the global flow of time which would stop the aging process which is impossible to do. Probably not the best explanation but ...

 

No.

Open and closed are contradictory definitions, like round and square. The universe cannot be both open and closed, it can be open or closed (or flat).

 

I was thinking along the lines of ... Over large scales the universe could be open and over small scales the universe could be closed but when we look out, across the universe, we accentually view it as being flat. You would call this a contradictory statement? I'm not trying to pick a fight or anything, it is just a thought.

 

No I know what you're thinking. And I suppose that it IS possible. But there would certainly be observational evidence, which we don't see. For example, we see the Hubble law being obeyed: the further galaxies are away from us, the faster we see them recessing. If your idea we right, we'd see a turnaround point somewhere.

 

I guess this would still be on topic seeing as it's about the shape of the universe.

What do you mean by 'turnaround point'? I can take this a few ways. It could mean that if I were traveling away from Earth, at some point during my journey, I would get 'turned around' and wind up back at Earth. I thought that this defines a closed universe. Or it could mean that there would be a point, somewhere, where the universe transitions from open to closed (a 'turnaround point' if you will) and because of this we would not see the Hubble law being obeyed?

 

Well really what I had in mind was that there should be somewhere where the expansion stops, and the contraction begins. At that point, the galaxies would be blue shifted because they are now heading back towards us.

But I suppose you mean that the observable universe is an expanding patch inside of a much much larger contracting patch. Is this what you mean?

 

I was thinking of it the other way around. The observable universe is an expanding patch 'outside' of a much much smaller contracting patch.

 

Oh yeah. We would see that I think.

There are things called domain walls and cosmic strings, which signal changes in physics like the one you're talking about (aside from the issues with Hubble's law, that I pointed out above). Domain walls and cosmic strings are topological defects. Morally, these are the same things as defects in crystal structure, as one finds in various condensed matter systems. Anyway, if such a phase transition happened in our universe, at some point in space, we'd see signatures of domain walls and topological defects in the CMB, which we don't see.

I think.

 

You could be talking about energy density differentials.

Take the CMB. It is an equalized energy density environment. If you increase the density by reducing the volume, the temperature goes up. If our patch was contracting we would observe the temperature increasing.

In the case of our observed CMB, it is connected to the Big Bang. It is inflating and inflation refers to the increase in volume as the universe expands. The temperature of the CMB is affected by the expansion and therefore as the energy density of the CMB decreases it equates to a decrease in background temperature. Unlike a spoon that cools when you remove it from hot coffee by radiating heat into the surrounding environment, in Big Bang Theory the CMBR has no place to radiate to. So if the universe stopped expanding the temperature of the background would stop cooling.

I think you are wondering about the possibility that there are patches of differing energy density in the greater universe. You would place us within one such patch. If that was the case, and if we couldn’t see the point where the energy density differential occurs, then we couldn’t detect any other patches that have a different energy density. It is possible that they exist but since we do not see any density boundary change (temperature differential) , we can be safe to refer to the known universe as one huge Big Bang connected expanding energy density environment whose background temperature has cooled through expansion form perhaps billions of K to the current ~2.7 K.

 

This was 'one of those question' that I wrote down a long time ago and never came across an explanation. I agree with Ben, there should be some kind of imprint in the CMB from the first moments.

This is a good point and it happens to be what we observe at small scales (the 'closed side').

 

can't life on earth and it's atmosphere that supports it be considered a universe itself?

it's definitely different from what's outside of it. there seems to be many universes.

no one knows if empty space is infinite.

 

I did check on whether there was a live thread, but I looked for "infinite" rather than "has an end".
That thread started earlier than mine, so perhaps people might better post there.
http://www.sciforums.com/showthread.php?t=98645

 

Ah yes. Univerce.
Shadow is from Tunisia.

You need to use a spelling checker Shadow.

If you use the English version of Google chrome, it will highlight any spelling mistakes.
I find it very useful myself, as the letter W on my keyboard is sticky.