Is the universe infinite or finite?

[Aupmanyav]

So each mind is a universe in itself?
Or there is only one mind, and one universe, but one which is experienced subjectively by it’s various components?

I think the universe is a dream within a dream within a dream. And for there to be a dream, there has to be a dreamer; it follows that the dreamer must exist beyond or outside the dream, therefore beyond time and space. This dreamer we may choose to call God. And we may choose to think it benign.

Of course I cannot prove any of this, using science or anything else. Better minds than mine are coming close I think, and may one day do so. But probably not to the satisfaction of their fellows. So it goes on.

I do not think so, though evolution has created brains in a species with very similar ways to perceive and respond. I do not believe in any universal mind. Where will it house its machinery?

Yeah, Advaita Hinduism and Buddhism accept the illusionary nature of the perceived world - 'maya'. The interesting thing is that we, the supposed perceivers too, exist in the same environment. We cannot normally dissociate with our environment. Being able to observe phenomena as disinterested observer is known as enlightenment, jnana, nirvana, moksha.
Well, theists have various beliefs in religions including in Hinduism and Buddhism (Mahayana). Call it God, Allah, Bodhisattva, etc.
Keep at it. Perhaps some day you will be able to sort out your beliefs in a way that is suitable for you.

 

[firedragon]

I do not think so, though evolution has created brains in a species with very similar ways to perceive and respond. I do not believe in any universal mind. Where will it house its machinery?

Yeah, Advaita Hinduism and Buddhism accept the illusionary nature of the perceived world - 'maya'. The interesting thing is that we, the supposed perceivers too, exist in the same environment. We cannot normally dissociate with our environment. Being able to do that is known as enlightenment, jnana, nirvana, moksha.
Well, theists have various beliefs in religions including in Hinduism and Buddhism (Mahayana). Call it God, Allah, Bodhisattva, etc.
Keep at it. Perhaps some day you will be able to sort out your beliefs in a way that is suitable for you.

I think a new thread should be opened to supplement every single other thread in order to facilitate your propagation of Hinduism and occasionally Buddhism even in a non-religious discussion about the universe.

 

[RestlessSoul]

You seem to have slipped from boundary to 'limits' - not sure if you mean the same thing. The surface of a globe doesn't have a centre.


No. You don't need an actual globe, in a third dimension, in order for the surface to make logical (mathematical) sense all by itself. The same could be true of the universe if it's closed in that way.



Don't get this at all. Why and in what way 'measurable'?

The surface is integral to the globe. Conceptually, these two are one.

The surface of a globe, without the globe, exists only as an abstraction.

Anything that can be measured must, by definition, have limits. The surface of a sphere can be measured.

 

[firedragon]

For the second law to be satisfied, universally, the usable energy of the universe has to be decreasing over time, since energy needs to go into entropy, which itself has to increase over time. Energy is being bled off into increasing entropy.

I asked this question from the proponent of the cyclic universe in this very thread but it was brushed off. Lets see with repetition it will be attempted.

 

[firedragon]

The surface is integral to the globe. Conceptually, these two are one.

The surface of a globe, without the globe, exists only as an abstraction.

Anything that can be measured must, by definition, have limits. The surface of a sphere can be measured.

I think you have not understood an analogy.

Some scientists explain the space-time curvature of the General theory of relativity with a cloth and ball. That does not mean the cloth is taken as a physical part of the universe. It is an explanation of how the universe behaves.

 

[ratiocinator]

The surface is integral to the globe. Conceptually, these two are one.

The surface of a globe, without the globe, exists only as an abstraction.

Conceptually, the two can be separated. The surface is has a self-consistent geometry and topology regardless of the actual globe. You need to get that we can't always use intuition in these circumstances. We know that the universe defies human intuition in many ways.

Anything that can be measured must, by definition, have limits. The surface of a sphere can be measured.

But has no boundary and no centre.

 

[Aupmanyav]

A surface is a boundary, surely?

Yeah, read about 'manifolds'. Manifold - Wikipedia

2 dimensional manifold, 3 dimensional manifold, 2 dimensional slice of a 6-dimensional calabi-yau manifold

 

[Aupmanyav]

I think a new thread should be opened to supplement every single other thread in order to facilitate your propagation of Hinduism and occasionally Buddhism even in a non-religious discussion about the universe.

I was not the first to use the word God in the topic. Our friend RestlessSoul did that in his post #68. I am an atheist and I do not have anything to do with Gods or Goddesses.

 

[RestlessSoul]

I think you have not understood an analogy.

Some scientists explain the space-time curvature of the General theory of relativity with a cloth and ball. That does not mean the cloth is taken as a physical part of the universe. It is an explanation of how the universe behaves.

I think I have understood perfectly well, thank you.

I am unconvinced by the analogy, which I consider too limited in it’s parameters to encompass the complexity of the question, and too imprecise to define it’s simplicity.

 

[ratiocinator]

The surface of a globe, without the globe, exists only as an abstraction.

Perhaps it would help if you consider that we can define self-consistent (and closed) surfaces with different properties that do not directly directly correspond with any three-dimensional object at all. The Klein bottle is such a surface, which we can sort of visualise in three-dimensions but only by making it pass through itself (see the diagrams and models on the page) but the mathematical surface does not have that self-intersection.

 

[firedragon]

I was not the first to use the word God in the topic. Our friend RestlessSoul did that in his post #68. I am an atheist and I do not have anything to do with Gods or Goddesses.

Very good.

 

[firedragon]

I think I have understood perfectly well, thank you.

I am unconvinced by the analogy, which I consider too limited in it’s parameters to encompass the complexity of the question, and too imprecise to define it’s simplicity.

Alright. Cheers.

 

[RestlessSoul]

Conceptually, the two can be separated. The surface is has a self-consistent geometry and topology regardless of the actual globe. You need to get that we can't always use intuition in these circumstances. We know that the universe defies human intuition in many ways.



But has no boundary and no centre.

But the surface, when separated from it’s object, has no material existence. For it to do so, it must be the surface of something.

I concede that intuition, like everything else in the observable universe, has it’s limits. I don’t expect to ever unravel the mysteries of the universe, and if someone far better educated than me ever does, I doubt many people, myself included, will understand whatever model he or she produces to explain it.

No reason not to grapple with these mysteries though.

The surface is a boundary. Geometrically, that’s arguably all it is.

 

[RestlessSoul]

I was not the first to use the word God in the topic. Our friend RestlessSoul did that in his post #68. I am an atheist and I do not have anything to do with Gods or Goddesses.

My bad, as the young people say.

 

[ratiocinator]

But the surface, when separated from it’s object, has no material existence.

Yes but the sphere is just an analogy that helps to visualise how the universe can be closed (finite) without a boundary. The actual theory involved (general relativity) is formulated on the basis that space-time is a four-dimensional pseudo-Riemannian manifold and that space is homogeneous and isotropic. The last conditions lead us to conclude that, on a large scale, the curvature of space is constant. If it's constant, it can be positive, negative, or zero ('flat'). The curvature is intrinsic and describes the geometry, there is no need for another dimension for it to curve in. In the case of positive curvature, the simplest topology is to assume that it's like (not is) the surface of a 3-sphere (a sphere in 4 dimensions). If it's negative it can't even be represented as a surface in higher dimensional Euclidean space.

This isn't just speculation - the analogy is a simplification of what the best theory we have about these things is telling us.

 

[Polymath257]

A surface is a boundary, surely?

The surface itself has no boundary. There is no place where you 'fall of the edge of the Earth'. So the *two* dimensional surface is finite in area and not bounded.

In a similar way, it is possible for a *three* dimensional geometry to be both finite in volume and not bounded.

 

[Polymath257]

Sure. Its interesting to discuss this in another thread and I can learn something.



Let me try and explain my question. A cyclic universe should have reached thermodynamic equilibrium because of increase of entropy, but it has not. The universe might reach the minimum protocol for entropy exchange because it could also decrease the size of cycles. If the total effect could mean the arrow of time reverses. The idea of a cyclic universe leaves the BGV theorem aside. In fact it rules the cyclic universe out. Also consider the so called "space traveller" who if keeps travelling at a critical or non-critical increase in speed he will achieve the speed of light eventually. This according to the BGV model makes the past eternality an impossibility. It also makes eternal inflation with no beginning an impossibility.

Please do explain what your position is since you proposed the cyclic universe.

Once again, entropy is a *statistical* property. it is very probable that it increases, but in the long run it would necessarily decrease at times. This is described by the notion of a Poincare recurrence time. This is related to the length of time it would take for the universe to return to a nearly equal state after a considerable time. necessarily, if this happens, entropy will decrease along the way.

Yes, the BGV theorem has assumptions that may not always hold, thereby negating their conclusion. In particular, the assumption that entropy always increases is violated. it is also quite possible that general relativity is not a complete enough model (because it ignores quantum mechanics) to say what is or is not possible.

When quantum effects are taken into account, the type of repeated 'bounce' that leads to a cyclic universe is still possible. Entropy is NOT a consideration because the relevant numbers of states (from which entropy is calculated) does decrease when going through a bounce.

 

[firedragon]

Once again, entropy is a *statistical* property. it is very probable that it increases, but in the long run it would necessarily decrease at times. This is described by the notion of a Poincare recurrence time. This is related to the length of time it would take for the universe to return to a nearly equal state after a considerable time. necessarily, if this happens, entropy will decrease along the way.

Yes, the BGV theorem has assumptions that may not always hold, thereby negating their conclusion. In particular, the assumption that entropy always increases is violated. it is also quite possible that general relativity is not a complete enough model (because it ignores quantum mechanics) to say what is or is not possible.

When quantum effects are taken into account, the type of repeated 'bounce' that leads to a cyclic universe is still possible. Entropy is NOT a consideration because the relevant numbers of states (from which entropy is calculated) does decrease when going through a bounce.

Cheers.

 

[Polymath257]

One practical problem with an infinite universe and a cyclic universe is connected to the second law. The second law states that the entropy of the universe has to increase. While an increase in entropy will absorb energy.

For the second law to be satisfied, universally, the usable energy of the universe has to be decreasing over time, since energy needs to go into entropy, which itself has to increase over time. Energy is being bled off into increasing entropy.

The energy being constantly bled off and lost by the universe, into entropy, will be conserved, but not in a net reusable way by the material universe, since the entropy of the universe has to net increase. The universe is not a perpetual motion machine as many seem to claim. The second law suggests a one time occurrence with a finite self life. The universe is like a living thing that ages due to the second law.

The question then becomes, what is nature of the energy stored within entropy? We know that it is not net reusable by the universe, due to the second law. Entropy is considered a state variable meaning any given state of matter has a specific entropy value that is measurable. Water at 25C and 1 Atmosphere, has a fixed amount of entropy that is always the same. In that respect, the energy within entropy is similar to specific information about a very specific state. We can retrieve some of energy in entropy, by simply changing the state; go to water at 20C and 1 atmosphere. However, we cannot get the entropy energy back while also leaving the state unchanged.

The living state, in general, and the brain, in particular ,generate a lot of entropy. The energy within that entropy, if conserved, would mean your essence or your many states of life and being; soul, are conserved by the universe within the universal entropy pool. The energy for that data storage come at the expense of the universe aging.

The problem with this reasoning is that entropy is mostly a description of the number of accessible quantum sates. We have observationally seen cases where the entropy of a system can decrease.

it is quite possible that the phase changes that occur that lead to 'Big Bangs' reset the number of available quantum states (most likely to one), thereby resetting the entropy value at each bounce.

The second law is a *statistical law*, NOT a fundamental one.

 

[Polymath257]

Cheers.

So you don't want to address the issues I raised?

I have given reasons why an infinite universe is a logical possibility. You have done little to argue effectively against those possibilities. In the case of entropy, it is simply true that entropy will decrease at times if the universe is infinitely old. But that is NOT a violation of any fundamental physical law, only a statistical law. And those low probability events *will* happen in an infinite time.