Thread: What's Out There?

I was never sure exactly on what the expansion referred to-- either the vacuum itself or the matter at the edge of the vacuum increasing the practical size of the universe.

And yes, there is 'something', and only one something you can ever be fully sure of: your own consciousness

It is space itself, not the matter. The universe sprung into existance with the big bang, it wasn't just a "matter" explosion inside the universe (I think). We will probably never comprehend "the outside". So it's the same question as the meaning of existance.

Originally Posted by person

The universe is supposed to be constantly expanding, but what is it expanding into? Is the absense of matter still considered the universe?

Imagine there was no limit, then where are we really? EVERYTHING is so confusing in that sense, I mean, if there is no universe, what is there? Does there have to be anything?
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Limits are useful as a frame of reference. We cannot effectively investigate any given topic without limits. Otherwise, a interaction would have no intent. Our entire culture would be in an ADD induced Stone Age.

We live in a universe made of matter and energy. As you said, this matter is expanding outward. The lack of said matter and energy is vacuum. Nothing exists within this vacuum. Scientifically, it is not considered a part of the universe.

Originally Posted by Merlin38

Limits are useful as a frame of reference. We cannot effectively investigate any given topic without limits. Otherwise, a interaction would have no intent. Our entire culture would be in an ADD induced Stone Age.

We live in a universe made of matter and energy. As you said, this matter is expanding outward. The lack of said matter and energy is vacuum. Nothing exists within this vacuum. Scientifically, it is not considered a part of the universe.
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Hmm, well vacuum spawns partcles all the time, which quickly dissapear again. The big bang spawned the whole universe eaven the vacuum. If you take out the matter and energy, as you say is the universe we live in, you will still be in the universe. A better word for it would be space.

So, your saying that the before the Big Bang, there was just a vacuum?

Hmm I guess then that there is no end, like if you lived in a room all your life, you couldn't comprehend an outside world. Just like we can't comprehend what's 'outside' the universe.

Shows how little we know or understand.

Matter is constant in the universe though isn't it?

Originally Posted by person

So, your saying that the before the Big Bang, there was just a vacuum?
Matter is constant in the universe though isn't it?
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If you're asking me, I'm saying that there was nothing (for us) beore the big bang.

Yup. a vacuum wouldn't accurately describe it, since a vacuum only has meaning when there's air to compare it to.

I've always been under the impression that there were an endless amount of universes, galaxies, dimensions, etc... and that if you could reach the end of this universe, you would just go into another one. There may come a day when the universes have become nothing but a chaotic mass once more, b/c in the future, all of the galaxies are supposed to be completely obliterated by the black holes that are in all of them (yes, even ours ). Though, even after that happens, the universe itself will still exist.

My guess is that there are other universes outside our universe. In all of the known nature, whenever there is something, there is another something outside of it. So I see no reason to believe that the universe would be different. But was is outside of everything including all the universes? I find the idea of infinite space impossible to comprehend, and I found the idea of finit space equaly impossible to comprehend.

Originally Posted by Chaos

I've always been under the impression that there were an endless amount of universes, galaxies, dimensions, etc... and that if you could reach the end of this universe, you would just go into another one. There may come a day when the universes have become nothing but a chaotic mass once more, b/c in the future, all of the galaxies are supposed to be completely obliterated by the black holes that are in all of them (yes, even ours ). Though, even after that happens, the universe itself will still exist.
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Yes, but if the universe exists long enough, the black holes will evaporate. There are many scenarios like that. Will it keep growing, or will it shrink, etc. Exit mundi handles scenarios like. It's quite a cool website. And besides there is nothing sad about black holes and other stuff like that, I think it's very cool .

My prefered representation of the "expansion" is this one: (described in the book The Fabric of the Cosmos)

Picture an infinite plane with dots at each integer coordinates: (x=0, y=0); (x=1, y=0); (x=42, y=-13)... forming a sort of grid. There is an infinity of dots, going already to the infinity. Those dots may represent galaxies at the present time.

Now, 1 second later, the "elastic" plane has inflated by a factor 2: dots have now moved to coordinates which are even: ..(0, -4000) ...(0,0) (0,2) (0,4)... (20,16), ....; There are still as many dots; they still go to the same "infinity" (infinity doubled is still infinity); but they are twice distant than before. You could say that all the distances in the "universe" have doubled, but the universe as a whole has not expanded in something else outside: it is still the same infinity, only more diluted.
And after n seconds, the dots are on coordinates of 2 at the power n.

If you reverse the time to go back to the "Big bang", you won't find a very dense dot at the "middle" of a "small" universe: instead, you will find that there is an infinity of dots which are 1/2 unit apart, before that 1/4, ... 1/billionth.... but still covering the entire plane. The "Big bang" would be an infinite plane completely black because "dots" are everywhere.

So it's more "empty space" (the space time itself, not just "vacuum") which is created inside the already infinite Universe, than an universe expanding inside something else.


Keep in mind that there is of course no absolute (x=0, y=0) origin which is the "center"; any point could be chosen and the final result would be the same.

I read somewhere that the universe was a fluctuation in nothingness. So assumably the edge of the universe would be nothing...

Maybe it's donut-shaped... so when you eventually get to the "edge" you appear on the other side like Mario Bros.

Of course. When in doubt, turn to video games.

What you are describing sounds more like a worm hole then the edge of the universe.

Well, I was being serious. I was saying that the universe might wrap around in a circle, making a donut shape. It might be a bit off topic though.

Originally Posted by Jeremysr

Well, I was being serious. I was saying that the universe might wrap around in a circle, making a donut shape. It might be a bit off topic though.
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No, it's not off-topic. That a theory as good as any others.

I've theorized that, if a person were to successfully reach the edge of the universe, and continued going. This person would simply wind up on the complete opposite side of the universe. This would be similar to a person traversing a planet, in a straight line, only to wind up where he or she started, from the very beginning.

Say you know the centre of the universe (if it is a sphere shape), then if you took a spaceship to the most far away star/planet/whatever then would you be at the 'edge'?

You're right Dodobird, the ideas of both an inifite and a finite universe are hard to comprehend.

Another point is if you look at the universe as a baloon. You can blow it up - the universe expanding, and it keeps growing. Now if you were in this universe then you would assume the edge of the baloon is the edge. But on the outside it is just growing into other space.
Does that make our universe inside others?

Anyone remember that Doctor Who episode where they had the other universes and the Cyber men...

Originally Posted by person

Say you know the centre of the universe (if it is a sphere shape), then if you took a spaceship to the most far away star/planet/whatever then would you be at the 'edge'?[/b]

I don't know if you were asking me personally. But based on my theory, there really wouldn't be a true edge. Think of "Pac-Man", and what happens when you move pass the edge of the screen.

But if you warp around like in pacman, then it should be sphere shaped, and a sphere is a finite shape, so what's upside of the sphere?

Well I think the 'sphere' they are talking about is a 3 dimensional representation of something consisting of a higher dimension. Thus, 'outside of that 4/5/6/whatever-dimensional sphere really doesn't exist.

I kind of hate the whole 'dimension' terminology.

Anyhow.

Perhaps just like pac-man. There is no world as pacman knows it outside the screen. And pacman can never know for sure about that world beyond his. I think it is the same for us.

Originally Posted by dodobird

But if you warp around like in pacman, then it should be sphere shaped, and a sphere is a finite shape, so what's upside of the sphere?[/b]

There would be no "warping". Don't look at the universe as a sphere, and when passing the edge, will magically warp you to the other end. Instead, look at the universe, as a domain, with a never ending edge. With no set boundary or limit. Look at is as, if I keep going, I will just keep going and going, until I end up where I originally started (x,y,z). Just like on Earth. If I start where I'm at now, and continue in a straight line long enough, I will end up right where I started again (x,y). And not because I magically warped there. I look at the universe as the same, but on a higher dimensional perspective.

Originally Posted by dodobird

Well I think the 'sphere' they are talking about is a 3 dimensional representation of something consisting of a higher dimension. Thus, 'outside of that 4/5/6/whatever-dimensional sphere really doesn't exist.

I kind of hate the whole 'dimension' terminology.

Anyhow.

Perhaps just like pac-man. There is no world as pacman knows it outside the screen. And pacman can never know for sure about that world beyond his. I think it is the same for us.[/b]

Exactly.

Originally Posted by petersonad

I've theorized that, if a person were to successfully reach the edge of the universe, and continued going. This person would simply wind up on the complete opposite side of the universe. This would be similar to a person traversing a planet, in a straight line, only to wind up where he or she started, from the very beginning.[/b]

I didn't quite understand what you meant earlier, but now I understand your theory. Seeing as how most astronomical bodies rotate in some form of circular motion, that makes sense.

Yeah it does.

Any thoughts on black holes?