Could the real size of the universe be infinite?

[Strange Me]

The observable universe is said to be about 96 Billion light years in diameter!

But after the Big Bang when space was created it might have expanded into Infinity?

Space itself without mass or energy is not limited to the speed of light c! So what stopped it expanding into Infinite size?

Of course size is not really the correct term but you get my drift?

[StringJunky]

It could be infinite. The 96blyr figure is just how far light can travel from out there to the earth before the universal expansion is too fast to reach us. This is what we call the 'observable universe'. We generally don't receive any information outside our observable sphere in any given moment, but the sphere does increase in size, so we gather more information eventually.

Edited July 7, 2021 by StringJunky

[J.C.MacSwell]

Current model for the Universe I think has it that if it is infinite now, it also was at the big bang, only denser at that point.

The Observable Universe has never been infinite.

Edited July 7, 2021 by J.C.MacSwell

[Airbrush]

On 7/7/2021 at 1:42 PM, J.C.MacSwell said:

Current model for the Universe I think has it that if it is infinite now, it also was at the big bang, only denser at that point.

Does that mean that there is no way for a big bang that is finite in size to expand to an infinite size?

[J.C.MacSwell]

2 hours ago, Airbrush said:

Does that mean that there is no way for a big bang that is finite in size to expand to an infinite size?

Based on my understanding of the current model, yes, at least in any finite amount of time.

Edited August 5, 2021 by J.C.MacSwell

[beecee]

On 7/7/2021 at 10:51 PM, Strange Me said:

The observable universe is said to be about 96 Billion light years in diameter!

But after the Big Bang when space was created it might have expanded into Infinity?

Space itself without mass or energy is not limited to the speed of light c! So what stopped it expanding into Infinite size?

Of course size is not really the correct term but you get my drift?

The WMAP probe showed that our universe was flat to within small tolerences, [flatness denotes infinite] still we can not be sure such flatness is not just a smaller part of a much larger curvature. What we do know is that the whole universe is much larger then the part we observe.

Also should be noted that the whole universe was not concentrated into a point at the BB, but the observable universe was.

http://www.astro.ucla.edu/~wright/infpoint.html

 

 

[Airbrush]

Our big bang may either be finite in size or infinite in size.  All we know about "the universe" comes from our view of OUR big bang.  There could be other big bangs or even a multiverse of branching bangs.  We like to call our view of OUR big bang "the universe" but our observable universe is only local.  So it seems like what we witness (big bang expansion) is a finite event, because the difference between finite and infinite, IS INFINITE.  Infinity is a tall order.  Even though it COULD be infinite in size, it is more likely finite in size.  There is more likely a region trillions or quadrillions of light years away where there is simply no matter or energy from OUR big bang.  That would be the rapidly expanding edge of our big bang. 🙂

Edited August 24, 2021 by Airbrush

[StringJunky]

14 hours ago, Airbrush said:

Our big bang may either be finite in size or infinite in size.  All we know about "the universe" comes from our view of OUR big bang.  There could be other big bangs or even a multiverse of branching bangs.  We like to call our view of OUR big bang "the universe" but our observable universe is only local.  So it seems like what we witness (big bang expansion) is a finite event, because the difference between finite and infinite, IS INFINITE.  Infinity is a tall order.  Even though it COULD be infinite in size, it is more likely finite in size.  There is more likely a region trillions or quadrillions of light years away where there is simply no matter or energy from OUR big bang.  That would be the rapidly expanding edge of our big bang. 🙂

WAG

[Airbrush]

8 hours ago, StringJunky said:

WAG

What is WAG ?

Edited August 25, 2021 by Airbrush

[iNow]

Wild Assed Guess

[geordief]

I have been told that "that would be the rapidly expanding edge of our big bang" is simply a wrong concept. (No edge)

[StringJunky]

7 minutes ago, geordief said:

I have been told that "that would be the rapidly expanding edge of our big bang" is simply a wrong concept. (No edge)

The process is one of all-over inflation, not a leading-edge explosion.

[geordief]

1 hour ago, StringJunky said:

The process is one of all-over inflation, not a leading-edge explosion.

Is there any theory as to how this process was initiated?

Which came first ,the observation of this  universal expansion or the theory that the observations validated?

 

(Hope I am not going off topic)

Edited August 25, 2021 by geordief

[StringJunky]

10 minutes ago, geordief said:

Is there any theory as to how this process was initiated?

Which came first ,the observation of this  universal expansion or the theory that the observations validated?

 

(Hope I am not going off topic)

 

Quote

Hubble provided evidence that the recessional velocity of a galaxy increases with its distance from the Earth, a property now known as "Hubble's law", despite the fact that it had been both proposed and demonstrated observationally two years earlier by Georges Lemaître.[10] The Hubble–Lemaître law implies that the universe is expanding.[11] A decade before, the American astronomer Vesto Slipher had provided the first evidence that the light from many of these nebulae was strongly red-shifted, indicative of high recession velocities.[12][13]  https://en.wikipedia.org/wiki/Edwin_Hubble

Someone here may have an idea of the steps leading to the initiation of inflation.

[Airbrush]

5 hours ago, StringJunky said:

The process is one of all-over inflation, not a leading-edge explosion.

I also would like to hear you explain the difference between these.  What is "all-over inflation"?  I've Googled it and wiki'ed it, and still can't find it.  Is it a WAG?

Edited August 26, 2021 by Airbrush

[StringJunky]

11 hours ago, Airbrush said:

I also would like to hear you explain the difference between these.  What is "all-over inflation"?  I've Googled it and wiki'ed it, and still can't find it.  Is it a WAG?

It was just a descriptive to differentiate from an explosion. In inflation, there is no central point of expansion.

[SergUpstart]

12 hours ago, Airbrush said:

What is "all-over inflation"? 

Inflation in the economy is the depreciation of the dollar, and inflation in the universe is the depreciation of the meter.

[swansont]

52 minutes ago, StringJunky said:

It was just a descriptive to differentiate from an explosion. In inflation, there is no central point of expansion.

Inflation and expansion are not the same thing. Inflation is an accelerated expansion (i.e. it's a particular form of expansion)

Having no central point is associated with expansion in general, not just with inflation.

3 minutes ago, SergUpstart said:

Inflation in the economy is the depreciation of the dollar, and inflation in the universe is the depreciation of the meter.

No, not so much. As above, changing scales is a feature of expansion, not just inflation. A meter isn't worth any less owing to expansion. Remember that expansion is only apparent where systems are not gravitationally bound to each other.

[Conscious Energy]

If evolution of time has a beginning, the system could not grow to infinity as it has limited Time to evolve. I think there is also an other limit on time (and so space) which is the current moment of Now. Or in other words the future yet not happened. If the system is Finite I think it is a Universally true so it is true for every physical entity in it meaning Enegy and Matter is not infinitely present in the system. 
 

If Space and Time would be infinite so should be Energy and Matter as well since There would be already infinite time for it to evolve if energy and matter formation would be also a causality. I.e a physical function explains its presence. If there is exactly the same amount of energy since the beginning there would be already infinite time passed to have infinite space between the finite amount of energy we suppose now is present in the system. I say there is absolutely now sign physically that there is infinity,

So I would say that the universe most likely Finite Now. Infinity is the Potential of Time to tick towards the Future.

[Airbrush]

I really want to know where exactly I went wrong with my WAG.  So I separated my points so anyone can easily address them and enlighten me to what is true and what is WAG.  Please be specific and not just ridicule me as a WAG.

1  Our big bang may either be finite in size or infinite in size. 

2  All we know about "the universe" comes from our view of OUR big bang (observable universe 92 LY across). 

3  There could be other big bangs or even a multiverse of branching bangs. 

4  We call our view of OUR big bang "THE universe" but our observable universe is only local and tells us little about what is beyond.  

5  So it seems like what we witness (big bang expansion) is finite, because the difference between finite and infinite, IS INFINITE. 

6  Infinity is a tall order.  Even though it COULD be infinite in size,  more likely it is finite in size.  There could be a region trillions or quadrillions or googols of light years away where there is simply no matter or energy from OUR big bang.  That would be the rapidly expanding edge of our big bang.

 

Edited August 26, 2021 by Airbrush

[MigL]

Where you 'went wrong' is considering the universe being finite with an 'edge', and that 'edge' expanding, or inflating, into something else ( other than the universe itself ).

The expansion/inflation is simply an increase in separation between things that are not gravitationally bound; Stringy gave the analogous description to your conjecture of an 'explosion', where the flame front travels outward.
This is the wrong view, as we can stand 'outside the explosion and see this effect; we cannot do so for the actual universe, as there is no 'outside' view that makes sense.

A lot of people seem to be unconfortable with the concept of infinity, and simply can't wrap their head around it.
But why is an 'edge' to the universe any less unconfortable ?
If you were at the 'edge', could you stick your hand through, or would there be a physical barrier ?
Is the physical barrier then, not part of the universe, needing another physical barrier beyond it ( and so on ... ) ?
And, if no physical barrier, once you've stuck your hand through, information has passed from 'beyond' to our universe, making'beyond' part of our universe ( and again, so on ... ).

Putting an 'edge' on the universe makes things infinitely more complicated.
Are you confortable with an infinity of complications ?

Edited August 26, 2021 by MigL

[zapatos]

3 hours ago, Airbrush said:

I really want to know where exactly I went wrong with my WAG.  So I separated my points so anyone can easily address them and enlighten me to what is true and what is WAG.  Please be specific and not just ridicule me as a WAG.

1  Our big bang may either be finite in size or infinite in size. 

2  All we know about "the universe" comes from our view of OUR big bang (observable universe 92 LY across). 

3  There could be other big bangs or even a multiverse of branching bangs. 

4  We call our view of OUR big bang "THE universe" but our observable universe is only local and tells us little about what is beyond.  

5  So it seems like what we witness (big bang expansion) is finite, because the difference between finite and infinite, IS INFINITE. 

6  Infinity is a tall order.  Even though it COULD be infinite in size,  more likely it is finite in size.  There could be a region trillions or quadrillions or googols of light years away where there is simply no matter or energy from OUR big bang.  That would be the rapidly expanding edge of our big bang.

 

Don't take the description of what you said as a WAG personally.

If you hypothesize something without any data/math/model it is a WAG. Saying something is a WAG is not ridiculing you.

I've made WAGs many times because I've had nothing better to go on and I had to move forward.

[studiot]

3 hours ago, Conscious Energy said:

If evolution of time has a beginning, the system could not grow to infinity as it has limited Time to evolve.

This is a misunderstanding of the nature of infinity.

 

Take an ordinary piece of graph paper.

Now mark scales along each axis, say 0 to 1 each way.

Draw a line from zero to 1, 1, straight or curved, it doesn't matter.

That line you have just drawn contains infinite number of points.

 

This is because of the particular nature of infinity that any sub interval of an 'infinite' line 'contains' an infinity.

[Conscious Energy]

11 hours ago, studiot said:

That line you have just drawn contains infinite number of points.

How can you prove that we do not count the same Planck unit?

Edited August 27, 2021 by Conscious Energy

[studiot]

1 hour ago, Conscious Energy said:

How can you prove that we do not count the same Planck unit?

 

Euclid Book 1 definitions 1,2 & 3.

Another interesting property to consider.

Here is a version of the sketch I asked you to draw.

Although of different lengths, all three lines OA, OB and OC contain exactly the same number of points as shown by the dotted lines putting them into one-to-one correspondence.

This can only happen with an infinite number of points if the lines are composed of 'planck lengths of equal length'