[CorneliusDalvert (OP)]

As I understand it our universe is pretty energetic even the vacuum on space still has high energy radiation whizzing through it and quantum foam bubbling away so why isn't the time space of our universe just expanding to fill a void ?

[Bill S]

Consider, perhaps, that if the Universe is all there is, it is just expanding.  The addition of "into nothing" confuses the issue, because it suggests that "nothing" is something into which the Universe could expand.

[timey]

That's an interesting and thought provoking perspective on 'nothing' at the other end of the scale there Bill! 

[Bill S]

So, where do you stand on this one, Vikki?

[Diogo_Afonso_Leitao]

You can see the expansion of the universe not as objects being being pushed apart, but as the very own fabric of spacetime expanding. This makes the expansion easier to understand.

[ProjectSailor]

The thought that it is expanding shows that it is not infinite.. and therefore there must be something external to the universe.

I feel we are tying ourselves down by saying there is nothing 'outside' the universe. for reasons above there is evidence that there is 'something' outside the universe even if that is void.

When we discuss universe are we discussing the observable universe? which should be everything created in our big bang.. and the question would then be.. could our universe be a bubble in the void with other unobservable bubbles from other big bangs?

The problem with these ideas are.. since they are unobservable they are disprovable and hence you can never confirm nor deny the existence of anything outside of the observable universe.

[evan_au]

It is my view that the universe is infinite, and time goes from infinity to infinity

How do you explain the Cosmic Microwave Background, which has a current temperature around 2.7K, and a https://en.wikipedia.org/wiki/Redshift#Highest_redshifts [Links inactive - To make links active and clickable, login or click here to register]?
- If the universe were much older, the CMBR would have a higher redshift, and a lower temperature.
- If the universe were infinitely old, you should see no evidence of CMBR.

[CorneliusDalvert (OP)]

Hi Bill S Why can't a 3 dimensional space contain nothing ? Could't the energy in our universe be compared to a form of pressure which is rushing out to fill an area of no pressure ? The steady increase in expansion could be caused by the increasing surface area of the "bubble" of our universe ,more surface more effect , just an idea or am I way off the mark ? If I've moved into moron country please feel free to tell me Also in terms of small scale nothing , isn't that what the planck length does , below that size energy has no practical effect so it may as well be nothing ?

[Bill S]

Why can't a 3 dimensional space contain nothing ?

What would stop the sides from meeting in the middle?

Could't the energy in our universe be compared to a form of pressure which is rushing out to fill an area of no pressure ?

In that model, wouldn’t the expansion of the Universe slow, or even stop, as the “pressure” rushed out?

If I've moved into moron country please feel free to tell

I’m poorly equipped to make that sort of judgement. []

Also in terms of small scale nothing , isn't that what the planck length does , below that size energy has no practical effect so it may as well be nothing ?

That’s an interesting way to look at it, but I doubt that the Planck length has any more influence on smaller scale objects than (eg) an inch has on the material being measured.

Saying that “below that size energy has no practical effect so it may as well be nothing” is similar to saying “this thing is so big it may as well be considered infinite.  That may work in many situations, but is only an approximation.

[evan_au]

matter and  antimatter repel

That is a hypothesis that you cannot back up.

Some physicists at CERN hope that this year, they will be able to produce enough low-temperature anti-hydrogen to accurately measure the force of gravitational attraction between matter (the Earth) and anti-matter (the anti-hydrogen).

By the way, most physicists expect that matter & anti-matter will attract. Some have suggested in the past that they might attract less, but we should know sometime this year.

[stevaneq]

I find the concept of the universe expanding into nothing difficult to comprehend as "expansion" suggests the universe is moving outwards and this suggests the universe has an "edge". I don't believe anyone has come up with
a solid and accepted"universe edge theory" but please correct me if I am wrong. Maybe the answers cannot be found in 3 dimensional concept of the universe but lie in the discovery of "other dimensions" which science may reveal in due course...

[timey]

So, where do you stand on this one, Vikki?

Well Bill,  I can see the possibility that it is by means of the gravity field that time occurs, and that between the occurrence of these 2 phenomenon, the dimensions of geometry emerge.

Therefore, under this remit, it is the gravity field that expands the dimensions of time and space.

Where there is no time, existence cannot exist.  How can we describe non-existence?  Can we call it 'nothing'?

[Thebox]

As I understand it our universe is pretty energetic even the vacuum on space still has high energy radiation whizzing through it and quantum foam bubbling away so why isn't the time space of our universe just expanding to fill a void ?

I think most scientists now agree that the visual Universe is just that, not finite but unseen by observation due to light stretching at distance and decreasing its magnitude giving us the inability to see in that zone from our zone.  Likewise can be assumed for objects beyond that boundary, that by time the light reflects from the object and reaches our eyes , there is not enough intensity of the carrier signal to see the object and also there is the inherent distance property of matter vanishing by vanishing point to sight.  A lot of scientists now conceive a multi-verse is beyond our vision boundary, although again this is just speculation of the beyond.  I do not think expanding into nothing is an appropriate term, I would say the visual Universe is inflating into the Unknown, which would be a factual answer with no speculation of the unknown.

[CorneliusDalvert (OP)]

Hi Bill re: What would stop the sides meeting ... I don't quite understand the question , surely volume has no prerequisite to what it contains ? re : In that model ,..Yes it would if the "pressure " could equalize however as it appears that space (not just our universe ) is potentially infinite that inflation ( thanks Thebox ) could continue until all the energy in our universe was spread pretty thin re: small scale everything has a practical limit , water stops being water when you get to  hydrogen and oxygen atoms , when an energy can't effect anything does it have a value of any significance ? I thought that's what the planck length implied below this size no measurable value ? Again if my knuckles are dragging on the floor throw me a banana and I'll be happy

[PmbPhy]

The thought that it is expanding shows that it is not infinite.. and therefore there must be something external to the universe.

That is not at all the case. An infinite universe can still expand. Think of it like this: consider an infinite flat plane which has a grid on in. At t = 0 the distance between a grid line and the next grid line is 1 meter. As time increases that distance increases. So the universe started off as being infinite and then it became even "more infinite". This is very valid concept in mathematics and as well in physics.

[Bill S]

  An infinite universe can still expand. Think of it like this: consider an infinite flat plane which has a grid on in. At t = 0 the distance between a grid line and the next grid line is 1 meter. As time increases that distance increases.

What you say is true of an unbounded space, but to apply it to infinity is at best a misuse of mathematics, and at worst "fairy-tale physics".  Apart from the mathematical approximations that we call infinities, infinity is so far outside the scope of our understanding that to apply to it the rules of our 3+1 dimensional Universe is just speculation.

So the universe started off as being infinite and then it became even "more infinite".

That makes no more sense than saying something started as being perfect, and became "more perfect".

[Bill S]

What would stop the sides meeting ... I don't quite understand the question

By definition a 3 dimensional space is finite.  To be in any way meaningful, if this space "contains nothing", you must be contrasting it with "something" outside.  I was thinking of "something" exerting greater pressure than "nothing".  However, it's probably simpler than that because if the sides are not touching, there is space between them.

[Bill S]

Therefore, under this remit, it is the gravity field that expands the dimensions of time and space.

Where there is no time, existence cannot exist.  How can we describe non-existence?  Can we call it 'nothing'?

Surely, if there is gravity there would have to be matter/energy to cause the gravity to exist.  If there is matter/energy there has to be space for it to emerge/exist in, and time to allow this to happen.  Gravity could do nothing unless time already existed.

[PmbPhy]

What you say is true of an unbounded space, but to apply it to infinity is at best a misuse of mathematics, and at worst "fairy-tale physics".

That is quite wrong. You've always had problems with the concept of infinity and this is another trouble spot for you. Any mathematician or physicist knows this to be quite correct and what it precisely means and it's correct.

That makes no more sense than saying something started as being perfect, and became "more perfect".

Bill - I have no desire to force you to correct misconceptions that people have. I'm only here to answer questions and point out mistakes that people make. After I do my best at that and they simply refuse to disagree with what the physics tells us, i.e. what cosmologists know to be the case and teach in their classes, I simply let it go at that.

All that I'm going to do at this point is to recommend that you download the following text on calculus

Calculus: Concepts and Contexts by James Stewart: http://bookos-z1.org/book/2428040/4cccc0 [Links inactive - To make links active and clickable, login or click here to register]

Turn to the section on infinity and read it very carefully. Good luck.

[timey]

Therefore, under this remit, it is the gravity field that expands the dimensions of time and space.

Where there is no time, existence cannot exist.  How can we describe non-existence?  Can we call it 'nothing'?

Surely, if there is gravity there would have to be matter/energy to cause the gravity to exist.  If there is matter/energy there has to be space for it to emerge/exist in, and time to allow this to happen.  Gravity could do nothing unless time already existed.

What you say is true Bill.  That's why I'm so keen to define the state of non existence, or 'nothing'.
As a mathematical enterprise within quantum mechanics, I suspect that this 'state' could perhaps be calculated, (under the correct remit),  to contain traces of an 'energy', possibly kinetic, that might initiate a quantum fluctuation, that carries mass, and would initiate the resulting gravity field, time, and the geometric dimensions of space , in the microscopic, """simultaneously""" as a reaction.  That this emergence of a fluctuation and it's associated physical effects would be an inevitability of the pre conditions of non-existence.
With regards to an expansion of these physical effects, these fluctuations would have to result in virtual particles that had 'the time' in which to take on the characteristics of real particles.
... This Bill, (chuckle) is of course highly speculative to say the least!

[CorneliusDalvert (OP)]

Hi timey just as with Bill S's over complication of a volume of nothing you seem to be making a mathematical stick to beat yourself with by over cooking the idea of nothing , I realise that time is then thrown into the mix as  "something" but  again other than more mathematical nightmares , I think it's best to view time as a frame of reference not a physical structure . I understand some theoretical mathematicians would disagree but I like a simple option Also I thought my post (" expanding into nothing " ) might get a reaction from the fans of eternal inflation but so far nothing (yes nothing ) 

[timey]

Sorry Cornelius, Bill and I have a bit of a history in talking in terms of nothing and time...in respect of a cyclic universe though... In my case anyway.

So... Inflationary Universe, Alan Guth and Andrie Linde stylie?

Bill , you've got some leaning towards the multiverse, eternal cosmos notion, don't you?  ...also, I think Pete might be a fan of Alan Guth, if I have read his previous posts correctly...

Aquarius, all good here thanks, you?

[Bill S]

After I do my best at that and they simply refuse to disagree with what the physics tells us,

 

Pete, I suspect that’s not what you intended to say, but I know what you mean, and I appreciate your help, and the ability to straighten out my many misconceptions..

You've always had problems with the concept of infinity and this is another trouble spot for you.

I have never argued with the use of infinities in mathematics.  My lack of maths means I would not be qualified to do that, even if I wanted to, which I don’t.  I understand that infinities are valuable in set theory, for example.  I know, in a very basic way, what Cantor discovered; e.g. that there are countable and uncountable infinities, that they can be of different sizes and that there is an infinite number of them.  So far, so good; but try to talk to the majority of scientists or mathematicians about extending thoughts about infinity beyond their “safe zone” of mathematics and it’s a bit like trying to talk to many Born Again Christians about evolution.   

….what cosmologists know to be the case and teach in their classes….

Of course cosmologists are right, and what they teach is invaluable in the progression of science.  I wish I had the opportunity to do the necessary background study, and then take some of these classes.  I would not even be tempted to digress into anything beyond the confines of the subject as taught. 

Having said all that, if something outside those confines made sense to me, I would not necessarily say: this is not what we are taught in class, so I reject it out of hand.

Back in the 1970s, when I was doing some original work on a local geological formation (Oaklian sub group of the Waltonian Red Crag) I made a series of appointments with professionals at the Natural History Museum in London to discuss the fossil fauna with them.  We very soon discovered that I knew more about that specific subject than they did. 

They could easily have said: what do you know about this, you don’t have the qualifications?  They didn’t. They were quite willing to accept some of my points about identification, and to acknowledge that I had taken the known vertical extent from 11ins to 8ft 5ins.

 In no way am I saying this situation is equivalent, only that a degree of open-mindedness is not a bad thing, however expert one may be.   

I'm now going to take your advice and download "Calculus: Concepts and Contexts".  Thanks for that.

[Bill S]

Bill , you've got some leaning towards the multiverse, eternal cosmos notion, don't you?

I try to avoid “beliefs”, I tend to see the multiverse concept as just one way of looking at some basic QM interpretational problems.  I’m not sure that it was ever intended to be “believed” as a physical reality.

The eternal cosmos idea is something quite different from the multiverse.  It arises from a very simple thought process:

1.  Nothing is precisely that – absolutely nothing.
2. If there had ever been nothing, there would be nothing now.
3. If 1 and 2 are correct, something must be eternal.
4. For convenience, I call this something “the cosmos”. 

This may be more “fairy-tale physics”, but it makes sense to me.

[Bill S]

I think it's best to view time as a frame of reference not a physical structure .

Does that differ from seeing time as that with which we measure change? I would be quite happy with that, but I accept that it may be no more than a poorly informed opinion.

I can't agree that seeing nothing as being "absolutely nothing" is in any way complicating the issue. 

BTW, I regard "absolutely nothing" as a tautology, on a par with "absolutely perfect" or "absolutely infinite".

[CorneliusDalvert (OP)]

Hi timey yeah that inflationary universe So as I understand it inflation is what gets our universe from a singularity to where experimental physics starts giving us a clearer understanding of actual events and in eternal inflation that model is used to explain dark energy . Our universe is just one of many and as a result  our universe  inflating into some kind of dense vacuum ? But if ( sorry about this BIG if ) our universe "condensed" out of the collapsing event horizon rather than inflating to fill a reasonable volume from a singularity then no need for inflation ? I understand that this may be physics from the university of never-neverland but as the only singularities that could be are hidden behind an event horizon why not ? After all it's the event horizon where it all starts to get weird and they have a volume
Hi Bill I'm always delighted when my poorly informed opinion makes someone happy , if the first part of this post made you laugh that too would make me happy I don't know enough to know when I'm wrong , so what makes me happy is to be told by those who do know And occasionally sometimes I'm given to tautology    

[puppypower]

I think it's best to view time as a frame of reference not a physical structure .

Does that differ from seeing time as that with which we measure change? I would be quite happy with that, but I accept that it may be no more than a poorly informed opinion.

I can't agree that seeing nothing as being "absolutely nothing" is in any way complicating the issue. 

BTW, I regard "absolutely nothing" as a tautology, on a par with "absolutely perfect" or "absolutely infinite".

If you think about the accelerated expansion of universe (space-time) what that also means is time is speeding up at an accelerated rate. This means the potentials of the universe are being used up quicker.

As an analogy, say we have two furnaces that are identical in all ways. One is placed in a slower more contracted reference and the other is placed in a faster more expanded reference. Side by side, the faster more expanded reference furnace will burn fuel as a faster rate due to time speeding up.

If we substitute factories for furnaces, with each factory making widgets with one defect per hour, the faster reference factory will be adding entropy at a faster rate to the universe. Is the universe observed to be burning itself faster and faster, with the rate of entropy speeding up, relative to the past?

[CorneliusDalvert (OP)]

Hi All Would anyone happen to know if the mass of quark gluon plasma has been applied to the volume of an event horizon generated from its Schwartzchild radius , to see if it generates enough gravity to be stable ? And if not there are  still particles to be cooked into a super dense plasma which could only increase the energy levels and mass ? Brought to you by the research department of never-neverland

[Bill S]

If you think about the accelerated expansion of universe (space-time) what that also means is time is speeding up at an accelerated rate.

In the reference frame of the Universe, surely, time continues to progress at one second per second.  Only if you could establish a reference frame outside the Universe (good luck with that []) would you observe time dilation.  Would you then see time speeding up as the Universe’s expansion rate increased???

 

. One is placed in a slower more contracted reference and the other is placed in a faster more expanded reference.

I acknowledge that this is a thought experiment, but some relationship with the real world is a distinct advantage. 
What are these slower and faster “references”? 
Are they reference frames in which change happens at a different rate? 
Does time pass more quickly in one than in the other? 
What is the relationship between time and rate of physical change in each?

[timey]

Cornelius.  Tbh I have not read much about this inflationary universe concept.   Only the wiki link .  Although, like Bill, I also try to avoid "beliefs" where physics is concerned, my 'leaning' is towards looking at the universe expanding from the very small, into the very large.

Matter condensing from an event horizon?  I watched this recently.

Perhaps black holes and the interpreted observation of the possibility that they may be ejecting matter via superluminal jets might ring some bells for this notion?

Sorry... it's all I could come up with

Also, puppypower... a particularly grumpy physicist, on another forum, once told me in no uncertain terms that the rate of time does not increase proportionally with distance in space.  It is supposed to increase in elevation near mass, but that this observed increase in the rate of time levels off in space. 

[CorneliusDalvert (OP)]

Hi timey thanks for the link I already knew about the high energy plasma in an accretion disc but I read about quark gluon plasma and how dense it was and I couldn't help but speculate about it . I started a new thread on this so maybe some nice cosmologist will tell me if I'm a total idiot