Is the universe infinite or finite?

[firedragon]

I think it's infinite, but I have a secret to help me fathom it... maybe it is still generated by a formula.

Please explain.

 

[firedragon]

When asking if the universe is infinite or not, the default is that this is a question about space, not time. And whether space is infinite or not depends, in part, on the curvature. In *that* context, closed means finite volume.

I said I did not mention the geometry of "spacetime".

Tell me Polymath. Can you explain what you are looking for in this post?

 

[firedragon]

The problem is that KCA is full of holes.

So please find a thread that is discussing it as a topic and you can refute it there.

 

[robocop (actually)]

Please explain.

Maybe its infinite but its generated by a pattern like a Mandelbrot.

 

[Ponder This]

This question comes out of curiosity to find the arguments of those who make both sides of the word "or". If this is a false dichotomy I would like to hear the other options to this as well.

A few atheists have been making a similar argument to "the universe is infinite" in this very forum when discussing the Kalam Cosmological Argument, which is the reason for this thought experiment if I may put it that way. Now before anyone derails the thread saying "this is a strawman" let me make it clear that this is not an atheists position in general, but a few do make this positive claim, thus what are the philosophical or/and scientific reasonings for this?

If this is about the Kalam Cosmological Argument, then in its basic form the Kalam argument does not reference the finiteness or infiniteness of the universe. The basic premises are:

1. Whatever begins to exist has a cause.
2. The universe began to exist.​

So it doesn't matter if the beginning of the universe was before an infinite causal chain or before a finite one. The conclusion would still be reached that:

3. The universe has a cause.​

So the objections ought to be to one of the premises and not just be an argument about the finiteness or infiniteness of the universe.

 

[firedragon]

If this is about the Kalam Cosmological Argument, then in its basic form the Kalam argument does not reference the finiteness or infiniteness of the universe. The basic premises are:

No. This is not about the Kalam Cosmological Argument. This is about the topic, an infinite universe.

 

[firedragon]

Maybe its infinite but its generated by a pattern like a Mandelbrot.

Thanks.

 

[Polymath257]

No. This is not about the Kalam Cosmological Argument. This is about the topic, an infinite universe.

And the simple answer is that we don't know whether the universe is finite or infinite in volume. Nor do we know if time is finite or infinite into the past. All four combinations are possibilities.

 

[Polymath257]

I said I did not mention the geometry of "spacetime".

Tell me Polymath. Can you explain what you are looking for in this post?

You asked if the universe is finite or infinite. If that is a question about the spatial extent of the universe, then the geometry of spacetime is relevant to the question. To answer your question requires some understanding of the geometry of space.

 

[firedragon]

And the simple answer is that we don't know whether the universe is finite or infinite in volume. Nor do we know if time is finite or infinite into the past. All four combinations are possibilities.

Can you give a model where the universe is "infinite into the past"?

 

[firedragon]

You asked if the universe is finite or infinite. If that is a question about the spatial extent of the universe, then the geometry of spacetime is relevant to the question. To answer your question requires some understanding of the geometry of space.

So please do provide a model where the universe is "infinite into the past"!

 

[Polymath257]

So please do provide a model where the universe is "infinite into the past"!

Like I said, most versions of quantum gravity have this characteristic.

Most of the systems that are based on the idea of a multiverse have time infinite into the past.

Systems having some version of a cyclic universe have time infinite into the past.

There are systems where things are symmetric about the time of maximum compression. In these, we are in an expansion phase that follows a previous contraction phase. In such, time goes infinitely into the past.

 

[firedragon]

Like I said, most versions of quantum gravity have this characteristic.

Most of the systems that are based on the idea of a multiverse have time infinite into the past.

Systems having some version of a cyclic universe have time infinite into the past.

There are systems where things are symmetric about the time of maximum compression. In these, we are in an expansion phase that follows a previous contraction phase. In such, time goes infinitely into the past.

I am talking about this universe. If you wish, the multiverse "idea" could be discussed in a new thread.

What about the entropy of a cyclic universe?

Think of the Borthe gorde vilenkin theorum. It says that the past eternal cyclic models are simply ruled out. Please provide an explanation to the conflict of cyclic universe model and the problems of thermodynamics.

 

[Marcion]

If the universe is finite, what lies beyond the boundary?

I would think the boundary is where light has managed to travel to. Beyond that boundary there is nothing, not even somewhere that you may call space.

 

[Aupmanyav]

Think of the Borthe gorde vilenkin theorum. It says that the past eternal cyclic models are simply ruled out. Please provide an explanation to the conflict of cyclic universe model and the problems of thermodynamics.

Kindly get the names correct. It is Borde-Guth-Vilenkin Theorem (Borde–Guth–Vilenkin theorem - Wikipedia).

There is no theory which science accepts as complete and final. Physics is a work in progress, perhaps will be that for a long long time. There are people who do not accept Borde-Guth-Vilenkin theorem.
"Theoretical cosmologist Sean M. Carroll argues that the theorem only applies to classical spacetime, and may not hold under consideration of a complete theory of quantum gravity. He added that Alan Guth, one of the co-authors of the theorem, disagrees with Vilenkin and believes that the universe had no beginning."

 

[Fallen Prophet]

This question comes out of curiosity to find the arguments of those who make both sides of the word "or". If this is a false dichotomy I would like to hear the other options to this as well.

A few atheists have been making a similar argument to "the universe is infinite" in this very forum when discussing the Kalam Cosmological Argument, which is the reason for this thought experiment if I may put it that way. Now before anyone derails the thread saying "this is a strawman" let me make it clear that this is not an atheists position in general, but a few do make this positive claim, thus what are the philosophical or/and scientific reasonings for this?

I believe that the Universe is divided into two basic categories - Organized and Chaotic.

Organized Space is the Kingdom of God and it is infinite only in the sense that it is ever-expanding without end.

Chaotic Space is the area outside of God's Kingdom which is filled with energy and matter and has no end.

 

[firedragon]

Kindly get the names correct. It is Borde-Guth-Vilenkin Theorem (Borde–Guth–Vilenkin theorem - Wikipedia).

Apologies. I didnt expect you to get so offended. Correction accepted.

There is no theory which science accepts as complete and final. Physics is a work in progress, perhaps will be that for a long long time. There are people who do not accept Borde-Guth-Vilenkin theorem.
"Theoretical cosmologist Sean M. Carroll argues that the theorem only applies to classical spacetime, and may not hold under consideration of a complete theory of quantum gravity. He added that Alan Guth, one of the co-authors of the theorem, disagrees with Vilenkin and believes that the universe had no beginning."

Okay. It seems like you are of the opinion the universe had no beginning.

Other than Sean Carrolls disagreement with the finite universe, what reasons do you pose to say that it was in fact infinite? Please explain.

 

[Aupmanyav]

Organized Space is the Kingdom of God and it is infinite only in the sense that it is ever-expanding without end.
Chaotic Space is the area outside of God's Kingdom which is filled with energy and matter and has no end.

Right. Got it. No energy or material in God's kingdom, only clouds.

 

[Aupmanyav]

Apologies. I didnt expect you to get so offended. Correction accepted.
Okay. It seems like you are of the opinion the universe had no beginning.
Other than Sean Carrolls disagreement with the finite universe, what reasons do you pose to say that it was in fact infinite? Please explain.

The first person, Borde, is of Indian origin (Arvind Borde). That explains it a little.
No, I belong to the other group who believe that universe has a physical cause for its creation, but it is certainly not God. The cause is related to physics of existence/non-existence. I believe that existence is a phase of non-existence and vice-versa. That is what is mentioned in RigVeda. What exists in the universe is not bound by the limitations of human imagination of existence and non-existence. That is why virtual particles flit into existence and back to non-existence.
Sean Carroll is one who is mentioned in the Wikipedia article. At the moment science has not said if the universe is finite or infinite. There are so many other options including 'many universe theory'. All that is an on-going research. We do not jump to conclusions.

 

[firedragon]

The first person, Borde, is of Indian origin (Arvind Borde). That explains it a little.

Alright alright. I have to give you that credit.

No, I belong to the other group who believe that universe has a physical cause for its creation, but it is certainly not God.

Thats irrelevant. So you can do that discussion in another thread.

Sean Carroll is one who is mentioned in the Wikipedia article. At the moment science has not said if the universe is finite or infinite. There are so many other options including 'many universe theory'. All that is an on-going research. We do not jump to conclusions.

Not what I asked.

So you conclude that you are undecided. Agnostic on this issue. Am I correct? Or do you take a position?