181 replies to this topic

[strike]

Does anyone accept the theory of the universe being infinite? I mean in one way it is way less complex, don't have to worry about edges. But on the other end, infinity almost necessitates every possible thing happening, and if there is anyway to travel faster than light through manipulating space or remotely finding life through it's connection to entropy or other ways, it seems like contact with aliens would be almost literally a 100% chance (but then percentages are pretty meaningless discussing infinity). And both those things seem like they could be a reality for THE MOST TECHNICALLY ADVANCED CIVILIZATION POSSIBLE (after how old the universe is).

What I am saying, is an infinite universe really realistic? I mean I know it is possible but it seems like there would be more evidence of that was the case.

-Strike

[David]

The problem is that we can only see things within our own "observable universe". Any light outside that point hasn't reached us yet since it's simply so far away... This makes it pretty hard to find evidence of the universe being infinite, which probably contributes to the concept seeming unrealistic. The only reason we know that it could be infinite is through mathematics and Einstein's laws.

[Kivitoe]

Does anyone accept the theory of the universe being infinite? I mean in one way it is way less complex, don't have to worry about edges. But on the other end, infinity almost necessitates every possible thing happening, and if there is anyway to travel faster than light through manipulating space or remotely finding life through it's connection to entropy or other ways, it seems like contact with aliens would be almost literally a 100% chance (but then percentages are pretty meaningless discussing infinity). And both those things seem like they could be a reality for THE MOST TECHNICALLY ADVANCED CIVILIZATION POSSIBLE (after how old the universe is).

What I am saying, is an infinite universe really realistic? I mean I know it is possible but it seems like there would be more evidence of that was the case.

-Strike

Well, it is always expanding, which means there has to be some end. If it was infinite how would the other universes in the cosmos be there if ours takes up all the space?

 

I guess black holes could be considered to be the end of the universe also because at their singularity, the space-time continuum starts to rip. I just wonder that if the s.t.c. rips there, if the objects and particles that reach the singularity get spit out on the other side of it, possibly another universe like ours that shares our s.t.c. or a void.

Edited by Kivitoe, 04 August 2016 - 10:28 PM.

[David]

Just because the universe is expanding doesn't mean that it has an edge or end. A lot of physicists believe that the universe has no edge; there's no place to go where the universe just ends and you could see what's beyond it.

Think of the surface of a balloon. If you were really small (like an ant, I guess) and you could walk on the balloon's surface, it would appear as though the surface is unbounded. Even though the balloon's surface has a finite number of square units, there's no edge or boundary to it. There's also no center on the ballon's surface.

The universe could be thought of as a three-dimensional version of the surface of the balloon, if you will.

Also, there is no evidence that supports the assertion that there are other universes. It's possible, but with our current knowledge we just don't know. And that's the thing with the universe: there's still so much for us to learn about.

[strike]

My point was that if other beings had the ability to manipulate space time to travel faster than light, wouldn't the observable universe essentially be bigger? Because the reason there is such a hard limit to the edge of the observable universe in the first place is the speed of light, yes? And it seems like the probability for other creatures traveling faster than light would be way, way higher in an infinite universe.

-Strike

[Russ]

The problem is that, with our current knowledge of physics, faster than light travel is impossible. Therefore, you could never travel faster than the rate of expansion of the universe and hit the edge. Plus, as David mentioned, the "edge" might not even be an edge in the way we think of it, but rather just loop around. It's something that (I believe) is still argued about.

(Caveat: Wormholes could possibly be used to, in a sense, travel fast than light, but you're technically never exceeding the universal speed limit, just taking a shortcut. And because it goes to a set destination, you still couldn't use it to hit the edge of the universe.)

[Dark Ice Dragon]

Other that the edge, i'm wondering how is the centre of the universe, if the theory of the big bang is correct, what remain of it after such explosion ? a immense empty place ?   

Edited by Dark Ice Dragon, 05 August 2016 - 04:59 PM.

[strike]

Faster than light travel is functionally still possible though. Like you said with warp holes but aslo Alcubierre (?) drives. And space moves faster than the speed of light often soo.

-Strike

[Timelord]

'Infinite', specifically references the continual expansion factor. If you could suspend time, the size would be finite, but the expansion factor means that by the time you discern the 'edge', it has already moved. The uncertainty of the location is a prevailing component in this model.

Heat death would also give the universe a finite size, if, or when that event occurs, whilst cold death may, or mayn't.

Essentially, the universe is a finite size at any given time, but its size is constantly changing. The multiverse theory is a separate issue to the size of this universe.

Regarding the centre of the universe.

Edited by ZoriaRPG, 06 August 2016 - 06:47 AM.

[Dark Ice Dragon]

New discovery on Pluto, the dwarf planet is emitting x-rays, is weak source  but it was unexpected. 

[strike]

Something I have been wondering about recently. Does the Big Bang need a cause? It really doesn't seem like it does. It is the beginning of time and causation does not make sense without time. It just seems like it does not need one at all.

-Strike

[Russ]

The general view, as I understand it, is that we can't really ask what caused the Big Bang because science breaks down at the Big Bang. There could have been something before it, perhaps, but it is entirely outside our view. For all intents and purposes, the universe, and time, began at the Big Bang so asking for a cause is a nonsensical question.

The Pluto thing sounds interesting. I'm gonna have to look into this.

[Eddy]

That thing on Pluto is really cool. From the little bit I read, it seems that its atmosphere is slowly being stripped away by solar wind. The solar wind collides with nitrogen, carbon and oxygen on Pluto's thin atmosphere, and then that causes electrons from these elements to escape into space producing an X-ray flare from the collisions.

 

I think that's one of the more likely explanations for the weird x-ray activity, but then again I haven't looked too much into this yet and that could be incorrect for all I know.

[strike]

It is only unknowable though because there is no coherent theory about quantum gravity, yes? Also to me it doesn't make sense to not ask a question because we can not 100% answer it yet.

-Strike

[Russ]

It's not a matter of yet. Yes, we lack a theory of quantum gravity, which is necessary for explaining several phenomena in the universe. But, as I understand it, that won't let us ask "What happened before the big bang?" It's not that better science is needed to look past it, but rather that cause an effect break down at singularities. We can't look past a singularity; it had destroyed any evidence of what came before it.

Of note, it is possible that there was no Big Bang after all, and our understanding of the universe is fundamentally wrong. In this view, the universe had no beginning but is not infinite. It could be thought of like earth, which is 2 dimensions (latitude and longitude) wrapped around a sphere, only the universe would be 4 dimensions, rather than 2. I don't pretend to fully understand, but I do not that certain scientists have endorsed this view.