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Unexplained Mysteries Discussion Forums > Science > Space and Astronomy
artymoon
I was just thinking of vacuum tubes and light bulbs, and the thought occurred to me: if space is a vacuum, how can it be infinite as many have said? Would it not have to be 'contained'?
Maybe this has been discussed already, if so, I apologize. original.gif
Any thoughts on this?
Waspie_Dwarf
Firstly there is no such thing as a perfect vacuum, although intergalactic space is darn close.

Think about your question though. In a light bulb why do you need to contain the vacuum? The answer is that outside the bulb there is stuff (mostly air in this case) trying to get in and destroy the vacuum.

If the universe is infinite, by definition it has no beginning or end. Therefore there can be no "outside". If their is no outside there is no stuff outside trying to get in. Therefore what do you have to contain it against?
artymoon
QUOTE(Waspie_Dwarf @ Jun 15 2006, 09:13 PM) [snapback]1233299[/snapback]

If the universe is infinite, by definition it has no beginning or end. Therefore there can be no "outside". If their is no outside there is no stuff outside trying to get in. Therefore what do you have to contain it against?

In order for a vacuum to work, doesn't it need to be 'pulled' though? If the universe is infinite, and a vacuum, what is pulling it?
Waspie_Dwarf
Nothing pulls on a vacuum. However outside pressure will force matter into a vacuum.

A vacuum is simply a lack of matter.

In the case of a vacuum inside a light bulb the air has to be pumped out (is that what you mean by "pulled through"). However in space there is no air, so you don't need to pump anything out.
artymoon
QUOTE
In the case of a vacuum inside a light bulb the air has to be pumped out (is that what you mean by "pulled through").
yes
QUOTE
However in space there is no air, so you don't need to pump anything out.

Why is there no air? Maybe it was pumped out.
AdNauseamSuiGeneris
Something else has always puzzled me as well as what you just said, I have always wondered... If the universe is constantly expanding... what was in the space it is taking up?
artymoon
QUOTE
If the universe is constantly expanding... what was in the space it is taking up?

wacko.gif
That's a fair question for those who believe it is expanding. thumbsup.gif
Avinash_Tyagi
One theory is that this universe is expanding into infinty until it collides with another universe and from the death of these universes other new universes will be created, hence the cyclic universe model.
artymoon
What if there is a force/s on the outer edges of the universe that is sucking in the universe and perhaps releasing what's left out another end. A black hole/s perhaps. I can only visualize it like- say a room(universe), with dust particles floating around(cosmic material). Place a vacuum hose in the air and turn it on. Slowly the dust particles in the room move toward the vacuum(considering the room is well sealed from outside air), even the particles from greater distances are being pulled. On another thread someone mentioned that distance galaxies are known to be moving away from ours...perhaps this is due to their closer proximity to a pulling force or black hole and not necessarily expansion.
Waspie_Dwarf
If your theory was right arty, everything would be rushing towards a single point. This is not the case. As you say everything is rushing away from our galaxy, but more than this, every galaxy is rushing away from every other galaxy.

Imagine a deflated childrens balloon. Cover that balloon in spots. The balloon represents the universe and the spots the galaxies. Now inflate the balloon. The surface area of the balloon expands. As it does so every spot moves away from every other spot. This is what is happening with the universe, except that the balloon is a two dimensional object and the universe is three dimensional.

As to the question of what the universe is expanding into:

Imagine you are a two dimensional being living on that balloon surface, As a two dimensional being you can only conceive of the dimensions forward-backward and left-right. You can not see the up-down dimension. You also can not comprehend that the balloon surface you live on is curved. From your point of view it seems flat. You know that your balloon universe is expanding because you can see that the dot galaxies are moving away from each other, but it is expanding into that third dimension that you can not see or comprehend (except mathematically). Now add another dimension. Think of a three dimensional universe expanding into a fourth dimension we can't see and that is what is happening to us.
artymoon
QUOTE(Waspie_Dwarf @ Jun 15 2006, 11:21 PM) [snapback]1233436[/snapback]

If your theory was right arty, everything would be rushing towards a single point. This is not the case. As you say everything is rushing away from our galaxy, but more than this, every galaxy is rushing away from every other galaxy.

What if more than one force is pulling...say multiple blackholes in multiple locations all sucking in, hence every galaxy 'rushing' away from every other galaxy. Is that a possibility?
Waspie_Dwarf
QUOTE(artymoon @ Jun 16 2006, 05:03 AM) [snapback]1233478[/snapback]

What if more than one force is pulling...say multiple blackholes in multiple locations all sucking in, hence every galaxy 'rushing' away from every other galaxy. Is that a possibility?


Every galaxy is moving away from every other galaxy. Even if you have tousands upon thousands of these black holes you would still have places where galaxies were getting closer together. That simply does not fit with the observations.
artymoon
QUOTE(Waspie_Dwarf @ Jun 16 2006, 12:32 AM) [snapback]1233499[/snapback]

Every galaxy is moving away from every other galaxy. Even if you have tousands upon thousands of these black holes you would still have places where galaxies were getting closer together. That simply does not fit with the observations.

What about Andromeda and the Milky Way? Even if the universe were expanding, galaxies would inevitably cross paths. Surely they wouldn't move away at the same rate...one could potentially catch up to another.
Waspie_Dwarf
It is true that nearby galaxies do merge and collide, but there are not the areas where masses of galaxies are rushing towards each other which would be required if your theory were true.
artymoon
QUOTE(Waspie_Dwarf @ Jun 16 2006, 12:53 AM) [snapback]1233510[/snapback]

It is true that nearby galaxies do merge and collide, but there are not the areas where masses of galaxies are rushing towards each other which would be required if your theory were true.

I'm not suggesting that they're "rushing" towards each other. Imagine multiple groups of galaxies being pulled towards their independent sources, the galaxies closest to their pulling source would potentially move quicker towards the source than the galaxies further away from the same source, creating an expansion effect.
Waspie_Dwarf
For this each group of galaxies would have to have a single black hole to pull it away in a unique direction. What is more these black holes would have to magically have no attraction for each other. It doesn't matter how, or how many times you modify this, it isn't going to work.
noyritus
The subject being discussed can not be comprehended. Maybe computer AI will advance to a point surpassing our awareness and can answer the question of space and time. But will we understand the answer and will it even care to share it.
artymoon
QUOTE(Waspie_Dwarf @ Jun 16 2006, 01:22 AM) [snapback]1233535[/snapback]

For this each group of galaxies would have to have a single black hole to pull it away in a unique direction. What is more these black holes would have to magically have no attraction for each other. It doesn't matter how, or how many times you modify this, it isn't going to work.

Thanks for your opinions. grin2.gif
artymoon
QUOTE(noyritus @ Jun 16 2006, 01:26 AM) [snapback]1233543[/snapback]

The subject being discussed can not be comprehended.

Now you tell me! Thanks a lot. laugh.gif
ThinkFurther
QUOTE(artymoon @ Jun 16 2006, 01:07 AM) [snapback]1233291[/snapback]

I was just thinking of vacuum tubes and light bulbs, and the thought occurred to me: if space is a vacuum, how can it be infinite as many have said? Would it not have to be 'contained'?
Maybe this has been discussed already, if so, I apologize. original.gif
Any thoughts on this?


I think you can ask that, and then you could ask how could it not be infinite. At some point we most likely have to have an infinite "layer" if you will, even if space is not. But if there were something beyond space (although it's unlikely), the laws of physics could be different there, etc. We humans just can't wrap our brains around how it can be possible, because to us it is impossible.

But then, you have no matter in space other than the solid objects like the stars and planets, etc. So if there WERE something outside it, unless the matter outside space were moved in some way, would space need containing? there is no outgoing or incoming force in space, no inertia. If something in space is at a complete halt, it can only be moved by something physically pushing it.

I dunno, it's quite worthless to ponder right now, it's just something we won't know anytime soon.
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