expanding universe >>>>>

[beren]

On page 93 of the March/April edition of Sky and Space is a thought provoking question and answer in the Astro-answer section. *How can the universe expand into nothing*is the question and one that usally pops up when friends and family ask how the astro stuff is going .Without understanding the theory i usally give the inflating ballon example but its a intriging subject and just wondering what other people think and whats your take on it :confuse3:

[Starkler]

I havent given this topic much thought but why cannot space be infinite and just matter from the original big bang expanding into empty space like an inflating baloon ?

As for the universe expanding into nothing it comes down to he definition of the word 'universe'. Is it all of everything, or all of space that encompasses matter ?

[rumples riot]

Two thoughts go through my mind.

One, maybe the universe has always been infinite and the bigbang was an explosion that happened within the Universe. That way the universe itself is not expanding its the material within it that is expanding.

Two, maybe the universe is contained within another space that contains infinite universes. If this is the case it would support some aspects of string theory. If matter in this universe vibrates at a certain frequency and you changed that frequency then it would be possible to slip into another dimension or universe. Some string theorists postulate this notion.

Personally, I think this question is too big for us mere mortals. I think our version of physics is too simplistic to understand this whole issue. If string theory does pan out to accomodate a unified theory then it will no doubt lead to our colonisation of space. However, for now I am happy to know that the universe is expanding and not contracting. Maybe the bigbang did not happen at all. Maybe the matter in our universe was the ejection of matter from a black hole from another universe, and it is expanding as a result of that ejection.

Man I don't know and now my head hurts.

[janoskiss]

The baloon analogy does not work like that. Ignore the fact that we appear to live in three spatial dimensions and pretend we live in just one! Then on the surface of the baloon imagine that two independent coordinates (say latitude and longitude) represent the space and time coordinates in our one dimensional universe. The expansion of the baloon represents an expansion of spacetime (and everything in it, which by the way defines it, ... General Relativity! :) ). In the beginning the baloon is a point, a signularity; time, space, everything are one. Then the Big Bang and the following inflation of the singularity into the "baloon" brings the myriad of seemingly distinct things you see before you and some others that you don't.

[ballaratdragons]

I personally agree with infinite space. What happens at the edge of the universe? A black wall? No way.

If the Universe did have an edge what is beyond the edge (and that is a common question put to scientists but they cannot say).

In my view, there cannot be nothing. The universe, if it has an edge, has to expand into something and that something is more space (remember, that's just my view of it).

I cannot prove anything, no-one can, but it seems pretty obvious that something cannot invade an area without an area being there to invade.

This is one of those debates that has lots of scientists saying dozens of theories and not one of them can prove anything, yet they stress over it.

I'm quite happy to know that space is out there, and we can look at it with a few bits of metal, plastic and glass from our humble little viewing spot here in our piece of the Universe. If it runs out, so be it. If it goes on forever, all the better.

Unlike Paul's problem, I DON'T want my head to hurt. I'll just accept space as space, and you can bet your bottom dollar that some ding-a-ling's going to come along and bring up the tired old comparison about a Flat Earth Theory.

[janoskiss]

Ken,
The points you raise are very much like those that would have been discussed hundreds of years ago on iceonearth forums, by people to whom it would have been "obvious" that the Earth (the ground) is flat.

If the flat Earth is not infinite then it must have an edge and then there must be something beyond that edge, even if it's not solid ground. Hence it must be infinite after all. But now we know the Earth's surface is finite AND it does not have an "edge"... And level ground is flat, even though it's curved. What bizarre nonsense!

Same sort of thing with the rest of the world. It may be infinite but need not be. And if it's finite, there is no issue with things beyond the edge because, somewhat like the finite ground under our feet, a finite universe does not need any external boundaries.

[ballaratdragons]

That's what I said,

"I think it goes on forever!"(infinite space).

I am a very curious person, that's why I am staring into space. I would love to know the answer, but I am not going waste my time debating something none of us can answer and I am certainly not going to burst a foofle valve worrying about it.

Space is space and I am going to enjoy looking at it, not debating about it.

Like my signature says "Look up and Smile" not "Look up and burst a brain cell"

[janoskiss]

One of us will just have to bite the bullet and do the experiment! :lol: Only real proof of any theory is expérience! :)

[RAJAH235]

Janos, How can *WE* exist/live as 3 dimensional beings in a 1 dimensional Universe to start with??????????? Thoughties??? :poke:
They/we, will never ever know, or be able to get to where ever the *edge/end* is to find/fall off anyway, so why not debate something that is more productive and understandable? Gees, Why worry about it? My first missus freaked out when you mentioned anything about infinity AND beyond???? WHAT is beyond infinity??? Give it a rest and enjoy our brilliant night skies while we have the opportunity to do so! Lifes too short! Let the Profs. hurt their brains. Can't even get to our nearest b***** star, never mind the ,,/m$%^^4u&@*&8nv. //mkih YAHHHHHH!!! L.
ps. I've worn out my fingers. :D
Coffee anyone ?

[ballaratdragons]

The Fact??? 3 dimensions???

Pretend??? I do live in one!



The Big Bang created everything???? inside nothing?????
Where did the Big Bang happen if there was nothing. That means there was nowhere for it to happen. It had to happen somewhere!

Look up and Smile, Look up and Smile, I must Look up and Smile.

Now I'm going Goo-Gaa, must be all those dimensions.

[janoskiss]

Beren, Have you read enough about "what other people think" yet? :P

[ballaratdragons]

Don't blame Beren, he lives in this 1 dimension with us.

It is a thread about what people <b>think</b>, not unfounded so-called facts.

Geez, MiG would love this one.

[RAJAH235]

Let's all get BEREN! Where is HE? L. :tasdevil: :thumbsup: :rofl:
ps. Thoroughly enjoyable. Thanks guys.

[janoskiss]

That's why I can't put anything past you, Ken! hehehe

What if other people like to think about such "unfounded so-called facts"? :P

[ballaratdragons]

:zzz2: :zzz2: :zzz2:

[rumples riot]

Interesting points guys, personally I don't think any of us is anywhere near qualified to answer this problem. Hey even the so called experts can't really agree. This is where I can't see one opinion being more right than another.

As Blackstone CJ once said "it is through powerful argument that great truths are established". Maybe there is no answer to this problem. If we apply 3 dimensional physics to the problem I would have to say that the universe is expanding into something. Because is has no logic to say that the universe is expanding, but not into anything. It is just expanding. 3D physics does not accept that notion.

Anyway all interesting arguments.

[RAJAH235]

Think I'll hang myself! Anyone got any STRING?? L.

[janoskiss]

Uhmm. Would you prefer a nostalgic 26+1 dimensional one or a modern 11-dimensional go-getter? hehe

[mickoking]

The universe is exanding into 'nothing' because space was created with the universe. The big bang did not happen in some pre existing void ie the universe was not created in a particular place at a particular time. And also time was created with matter and space at the big bang.


I also believe there are infinite universes ;)

[ballaratdragons]

LOL! Micko, It might help to start your post with the prefix 'I believe'.

[mickoking]

Sorry mate;) What I said I assumed to be the accepted model of the big bang.

BTW what do YOU believe? How do you think the universe can expand into nothing?????

[ballaratdragons]

It can't, that's why I believe the Universe is infinite.

My belief is that it goes on forever . . and ever . . and ever . . .

[mickoking]

If you think the universe is infinite do you believe it's existed forever?

Does it have infinite mass?

;)

[ballaratdragons]

Yep! I believe it's always been there and and always will be. The stuff in it changes but the 'Universe' just 'is'.

Does it have infinite mass? I dunno, I'm just an amatuer observer, what do I know about Mass.

Oww, there goes my brain again :sad:

I don't know the answers, but I love looking at it all :)

[mickoking]

Stevo's with me:rofl: :rofl: :rofl: :rofl:

[Orion]

All I can say is...now that's a smile :P

[avandonk]

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I know I should not do this but here goes.

Before the Big Bang there was nowhere and nowhen. That is Space and Time did not exist.A fraction of a second after a very large amount of energy was expanding so causing the existence of space and time. We cannot know what happened before as there was no before. As this energy cooled due to expansion then elementary particles could form protons electrons etc. the only atomic nuclei that were produced was Hydrogen Helium and a litte bit of Lithium. To produce all the elements we see today stars had to form by the gravitational accretion of these elements. These stars could only produce the heavier elements up to Iron by nuclear synthesis. Elements with a greater atomic number can only be produced in a Supernova.<o:p></o:p>

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The universe is not expanding into anything. It is just expanding and it need not have a boundary. If you don’t believe something can come from nothing it is happening right now everywhere particles appear and disappear due to quantum effects. This can be measured.<o:p></o:p>

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The really scary thing is because of entanglement every particle in the universe is entangled with every other particle as they were all once in the same place. This quantum entanglement is not understood and works over vast distances apparently faster than the speed of light. This really bothered Einstein. Dark Mass and Energy must somehow be related to this Quantum Entanglement. These connections must be through other dimensions we cannot perceive directly.

Life is just an inevitable result of the Universe heading towards more complexity rather than the reverse. Consciousness is an even more remarkable inevitable outcome. My firm opinion or belief is that all things are connected at a quantum level as it explains a lot of the unexplanable. Your body's physical boundary has no more reality than the physical boundary of the Universe. You are inexorably linked to everything else both through Space and Time.

Makes you think doesn't it.

Bert
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[janoskiss]

I really enjoyed reading the longer version of your post Bert! The one I got by email about quantum entanglement and such. :eyepop: Undelete, please! :prey2: It would be a great read for everyone; give that old grey matter something to do besides going over the same old same old. :)

[mickoking]

G,day Bert,

I really enjoyed reading your post and I am very much in agreement with it. It is a difficult subject to get one's head around because it is a long way from classical/ Newtonian science and is somewhat Metaphysical.

[gaa_ian]

Great post Bert
Very well put, you are correct that many of these phenomena are measureable.
This was really bought home to me by a lecture given up here in Gove by Prof Ray Norris from CSIRO.

[janoskiss]

Bert, sorry, I didn't realise your post was still here in its entirety! In the browser I was using only the first 3 and the last sentences show up followed by "Bert" and then the signature. :shrug: In Firefox I can see the whole post. :confuse3: I thought you deleted most of it after posting it. :doh:

I source view mode I see in there is some xml stuff / formatting in there that this browser does not seem to understand...

[avandonk]

I am in the habit of typing posts in MS word since after a long type lost the whole lot due to a crook connection to IIS.

I realized some years ago that Chaos Theory virtually discounted the idea of Destiny and Fate (clockwork universe). The Universe is far more forgiving as it allows you to take limited control of your own future by your own actions. My interest is because of forty years of reading the latest and best of science. I do not have all the answers but a lot of questions. I have long tried to put together everything I have learned and seen from all fields. It is difficult as I am only a limited life form that is not too smart. To put these ideas into plain English is difficult to say the least. I am surprised I have got so far.

Bert

[space lover]

Wow, so many answers and theorys.
Well, the universe is expanding, but has any one thought that it could somehow shrink as well? And simce the universe is expanding could it also stop becasue of some sort of barrier?

[janoskiss]

Yes, it could shrink, and it could stop expanding too. Not because of "some sort of barrier" like a balloon expanding inside a room and hitting the walls, but because of some inherent "potential barrier", a critical point where the process might reverse, like a pendulum's swing reaching its highest point, stopping, and reversing direction.

There is no external space in which the universe is doing its expanding. It is space itself that is expanding. The distance between any two points is increasing over time, that is all. Whether space is finite or infinite has nothing to do with this. And if it is finite, it is more in the sense of a circle having a finite circumference even though you could traverse it round-and-round for ever (i.e., finite but no boundary), and not in the sense of a straight ruler which has a finite length because it has two end points a finite distance away, which you can go beyond and step off the edge.

[space lover]

Good answer.
But, does anyone know at what rate the univers ie is expanding?
Could the rate be fast enough, so thats space expanded so much that the Andromeda galaxy woul never reach us, since Andromeda is heading towards us at 148,000kmh. Or is the expansion of the unviverse much slower.

[mickoking]

Not only is the universe expanding it is Accelerating.


Our universe gets more interesting all the time ;)

[janoskiss]

I have Peebles' "Principles of Physical Cosmology" here, which I'm slowly working my way through. (Picked it up by chance at a book sale for $10 last year. It's a great book on cosmology with lots of detailed observational evidence and not much beyond high school maths. Anyway...)

For the expansion of the universe, we have Hubble's law which says that the distance between two points is increasing at a rate of Hubble's constant times the distance. So the further apart things are the faster they are moving away from each other. Kind of like when you stretch something (rubber band, a piece of fabric, balloon): two points close together move apart slower than two points farther apart.

Now let's see what this says about Andromeda, after a bit of googling.

- The distance between us and Andromeda is 2.9 million light years
- Hubble's constant is about 2.5 x 10^(-18) Hertz (2.5 billionth of a billionth of an inverse second)
- That gives a rate of expansion (the product of the above two quantities) of about 250,000 km/h between us and Andromeda.

If Andromeda is heading for us at around 150,000 km/h like you say, then what Hubble's law says is that if it was not for the expansion of spacetime, Andromeda would be approaching us at about 400,000 km/h.

[Argonavis]

My understanding is that the expansion of space time does NOT affect the local group, or any other galaxy cluster. Andromeda is unaffected by the expansion of space time as demonstrated by Hubble. This is because this expansion is overcome by the effects of the local gravity field. If you took the expansion of space time away tomorrow Andromeda would still be speeding towards the Milky Way at the same speed as now, as this is driven purely by gravity and not by the "Hubble flow". Conversely, if it wasn't for the gravitational attraction within the local group, then Andromeda would be accelerating away at the rate of the Hubble flow, just like the rest of the Universe.

The gravitational effect within clusters is called the "peculiar velocity" and it is only when you get beyond the local group of galaxies do you observe the effect of the Hubble flow expansion of space time. All galaxy clusters will maintain some sort of integrity in spite of the expansion of space time, due to the effects of local gravity, principally from their dark matter halos.

Eventually, all the visible galaxies and galaxy groups will expand over the edge of the visible universe and we will be just left with the local group of galaxies to observe in our telescopes, or rather what is left of them after various merger events and exhaustion of their gas and dust through star formation.

[danielsun]

Or is the big bang just one of many cycles? Has it happened before?

[danielsun]

Although with the universe expanding and accelerating it would brobably dissmiss that theory. but then again you would think that all the material in the universe had to come from somewhere even at its compressed state before the big bang, and what triggered it to bang?

As a youngster when i first read about the big bang i thought that maybe all the black holes would eventually suck in and cosume thier host galaxy's and then maybe eventually collide with other black holes (and dead star black holes) and merge and keep consuming everything and so on until the pressure so compressed cause another bang!!!
just my 2 bobs worth!!!
At the moment im reading Stephen Hawking's UNIVERSE IN A NUT SHELL very interesting read!!!!!

[mickoking]

Black holes will inherit the universe........well maybe ;)

[rumples riot]

Got to find one of them first. No real conclusive evidence, just some corrobative evidence at this stage. Maybe blackholes are just the doorway to the next universe. Still it makes you wonder what our universe is expanding into??????

[hector]

Hi all
In answer to rumples last responce "TOMORROW"

The expansion of the Unvierse must include the increase of time.
Time is a one way effect. the law of cause and effect is a very real thing.
This is best demonstrated by Entropy.
so any discussion of an expanding universe must include the expansion of time.
Even if the spacial dimensions of the Universe were static it could still be said to be expanding due to the passage of time.
:scared:
I must be getting OLD!!!

[janoskiss]

Yes expansion is meant to apply to spacetime, i.e., space and time which Einstein showed are different aspects of the same thing.

If the expansion is allowed to continue unimpeded then for time that means a "kind of" slowing down and an eventual stop. I say "kind of" because things can only really slow down if someone with a stopwatch can measure that slowdown. But in this case the stopwatch would be slowing down too...

The concept of time has to do with the ordering of events and, in practice, with relating the frequency of seemingly regular events to other more random seeming ones. But when all things get far enough apart and there are no observable events left at a given location in space then time ceases to have any meaning there. But there can be no one there to appreciate the end of time, because if there was then their very existence would be defined by a series of many events and their order, and hence time.

Time cannot exist where nothing ever happens. It's kind of the other end of the breakdown of physics in the Big Bang picture: the distant future... As opposed to the distant past, the event of the Big Bang itself, which cannot be understood, or more precisely, makes no sense in the context of our current understanding of the physical universe.

[mickoking]

As our universe continues to expand it will eventually become impossable for sentinent beings to exist (for a variety of reasons). When this happens the universe will cease to exist, because no one is around to percieve it.


This might sound airy-fairy but thats my view on the subject. The universe is because we are.:confuse3:

[janoskiss]

Is that a tree falling in the woods...? :)

[mickoking]

Exactly