Unidentified Object in Space, Scientists Puzzled

[Khamsin]

There is a line of thought that argues our universe is a finite 3+1 D bubble in a larger universe, which may be infinite itself.

Unfortunately, it is rather difficult to even consider ways to prove an idea like that.

Given that the laws of physics here are the same as everywhere, including outside the bubble, and in any hypothetical other universes, wouldn't we be able to determine if such a thing is possible/likely? Or at the least, wouldn't we be able to say that it is not likely given the same reasons it's not likely our own universe is infinite?

Also, given that space is expanding, wouldn't that also mean the space between objects, molecules, atoms, subatomic particles, etc. is expanding, too? Do the forces of attraction between particles have to overcome some other force that would otherwise separate them via this expansion? Do the particles furthest from the center of expansion "drag" along particles closer in, given that the outer ones should be moving further than the inner ones?

[Kaylia]

We can't say anything about a super-universe at this point. People often propose such model because of the black hole, but there isn't any scientific evidence that our universe is anything like this. I've to admit that blackhole and Big bang do share similarities (both involve Plank Scale singularities), but it doesn't mean anything


When we say the laws of physics are the same everywhere (first postulate), we aren't talking about our current understanding of them, but about the actual laws. If there was a higher universe, our current physics would just be a part of a bigger and more general physics, and couln't be used to understand what happen above us.


Any space, including the one between molecules and atoms, should expands. However, the force that ties them togeter won't change, and their actual position will remain the same.

[edit]
Actually, I should say that space itself wouln't exist if there was no matter. The expansion is a consequence of having matter in our universe, and the opposite (expansion affecting matter) would just create an action/reaction loop .

[Max™]

I'm going to agree with Kaylia to a point.

The expansion of space won't affect matter for a very long time, but as there are indications that matter and space may be the same thing (not just my theory it turns out), it can be safely assumed that at some point the persistence of matter will lose out to the cold logic of entropy.

I had a recent thought, very surprising at that, which goes right to my earlier statement that the LHC couldn't produce a black hole, even if the energy densities were technically high enough.

Why do we assume black holes contain singularities?

Because our physics breaks down at the event horizon, and attempting to project them beyond it produces absurd results.

Why do the physics break down? This is tied to why black hole mass seems to correspond to area, not volume.

Because the event horizon is where our physics stop, and anything inside does not necessarily have to correspond to them.

The reasoning behind black holes producing universes didn't come from singularities.

It came from realizing that the event horizon could be simply described as an edge, a terminus, a point where worldlines cannot cross and return. So technically, we know that there are other universes, they're right there inside of the black holes.

This doesn't seem sensible if Hawking radiation and evaporation hold true, luckily, I don't believe they do, as the quantum postulates they're based on are inherently illogical, and as I prefer the model I'm working on where locality is preserved at the cost of absolute causality suffering some.

If black holes don't evaporate, then they violate the strict increase of entropy.

What is a violation of entropy? Maintaining some value of order within a system.

Rather like an egg unscrambling itself and putting it's shell back together.

Where does that order go if black holes don't evaporate?
We can safely assume that the universe is trending towards an entropic heat death.

If the black holes are still there after the heat death, which current signs suggest they will be, even in some versions of hawking radiation models, then the event horizon will not.

What do you get if you have a region of extremely densely folded spacetime with nothing preventing it from unfolding any longer?

A big bang.

[Woozie]

Given that the laws of physics here are the same as everywhere, including outside the bubble, and in any hypothetical other universes, wouldn't we be able to determine if such a thing is possible/likely? Or at the least, wouldn't we be able to say that it is not likely given the same reasons it's not likely our own universe is infinite?

Also, given that space is expanding, wouldn't that also mean the space between objects, molecules, atoms, subatomic particles, etc. is expanding, too? Do the forces of attraction between particles have to overcome some other force that would otherwise separate them via this expansion? Do the particles furthest from the center of expansion "drag" along particles closer in, given that the outer ones should be moving further than the inner ones?

We can't say anything about a super-universe at this point. People often propose such model because of the black hole, but there isn't any scientific evidence that our universe is anything like this. I've to admit that blackhole and Big bang do share similarities (both involve Plank Scale singularities), but it doesn't mean anything


When we say the laws of physics are the same everywhere (first postulate), we aren't talking about our current understanding of them, but about the actual laws. If there was a higher universe, our current physics would just be a part of a bigger and more general physics, and couln't be used to understand what happen above us.


Any space, including the one between molecules and atoms, should expands. However, the force that ties them togeter won't change, and their actual position will remain the same.

[edit]
Actually, I should say that space itself wouln't exist if there was no matter. The expansion is a consequence of having matter in our universe, and the opposite (expansion affecting matter) would just create an action/reaction loop .

Actually, the expansion does affect matter. I think we interpreted Khamsim's question differently, because I'm sure you're already aware of everything I'm about to say here. The answer to Khamsim's question:

"Also, given that space is expanding, wouldn't that also mean the space between objects, molecules, atoms, subatomic particles, etc. is expanding, too? Do the forces of attraction between particles have to overcome some other force that would otherwise separate them via this expansion?"

is yes.

Since the universe is expanding, the space between particles is expanding as well. This does affect the force between particles. Eventually, the expansion is going to be so extreme that stars and other objects on the edges of galaxies will not be able to communicate gravitationally with objects in the center. By "communicate gravitationally", I mean gravitational influences emitted by one will never reach the other. That's because the expansion of the universe will cause objects that far away to expand away from each other faster than the speed of light.

As a result, galaxies will no longer be able to stay together via gravity. They will be ripped apart.

As the expansion increases, this same effect will cause solar systems to be ripped apart. Then stars will be ripped apart. Then planets, then eveutally every single particle in this universe will be completely isolated from every other particle in the universe because the expansion between them is faster than the speed of light, meaning no two particles in the universe will ever be able to interact in any way whatsoever. So the universe will be entirely ripped apart.

This scenario is known as the big rip. It's expected to occur in about 20 billion years.

There's a very interesting article in Scientific American about how the expansion of the universe is going to affect matter and our scientific viewpoints of the universe. What happens is that eventually, all of our evidence for the big bang will disappear. Scientist of the day studying cosmology will never even guess that a big bang is a possible scenario because all of the evidence for it is no longer around (unless, of course, they still have historical records and they can look back and see that at some point billions of years ago, there was plenty of evidence. But if these scientists are starting from scratch, they'll never be able to justify a big bang theory). I can't remember exactly how or why the evidence of the big bang will be erased. I'm going to look for this issue of SciAm to see what month it was in so that you can order the back issue and look it up of you want.

[Kaylia]

If there was only matter and expansion, there would be no Big Rip. You need another increasing form of energy/force (dark energy) to rip apart everything. While we know something like this exist, it's way too early in my opinion to predict the fate of the universe when we don't know half of the parameter.


What I was saying is that space is created because there is matter. You put one atom in a place where "nothing" exist, and space/time will be created around it. The stretching we observe is just a consequence of matter flying around in every direction (and this is a direct consequance of the bigbang, dark energy and gravity).

[Max™]

In my model (interestingly, a similar one to that recently proposed by Lee Smolin for Loop Quantum Gravity) matter is nothing but knotted space.

What we observe is dark energy is tied in my understanding to time in the sense that you can find a direct correlation between the mass of an object and it's interaction with time, same with energy. High mass/energy = low interaction, zero mass/low energy = high interaction.

As the universe grows old, the time interacted with by space has to increase, and thus the amount of energy represented by undisturbed space has to decrease.