The Big Rip

[johnhuey]

I have a question: As inflation expands space at ever increasing speeds, it has been proposed that it will begin to tear apart the very structure of matter. The so called Big Rip - So what is the theoretical impact of the Big Rip when it hits a Black Hole?

[freeztar]

Interesting question, but I believe an unanswerable one because:

How can you have a black hole 'beyond' space?

 

I'm not familiar with the Big Rip concept, but if it tears matter apart, then one has to wonder how the matter exists beyond inflation. Looks like I have some reading to do...

[jungjedi]

micheal green has proposed a model in which calib-yau space can rip.

New Developments in String Theory

[TheFaithfulStone]

That is interesting.

 

A quick search reveals that apparently the effect of Hawking Radiation, which is theorized to evaporate black holes - gets more and more pronounced as the amount of dark energy (and thus presumably the gravitational pressure differential between the event horizon and "normal" space) grows. This means that the black holes start to evaporate faster and faster, and eventually, like everything else, just vanish.

 

I guess, this means, that normally, space kind of "eats away" like an Alkaseltzer in water. Imagine the temperature differential of the water and the Alkaseltzer getting bigger, and larger and larger chunks of the Alkaseltzer coming off. I think.

 

NB: I pieced this together from reading reviews and abstracts of this Gonzales-Diaz article from around the internet.

 

My understanding is probably incomplete. YMMV.

 

TFS

[TheFaithfulStone]

After reading your article (with some difficulty, and a curse for the web designer who set white Georgia on a black background on that body!) I am struck that in addition to being a neat mathematical concept Calabi-Yau Space would make an awesome name for an interstellar alien empire.

 

"We represent the Third Protectorate of Calabi-Yau Space! Submit to our holonomy, or we will crush you in our differentiable manifolds!"

 

TFS

[our hero is terrified of differentiable manifolds, but soldiers on anyway]

[Southtown]

After reading your article (with some difficulty, and a curse for the web designer who set white Georgia on a black background on that body!)

Right, I can't endure that ****, at least not for string theory.

[freeztar]

Right, I can't endure that..., at least not for string theory.

 

Use print preview.

Set the magnification.

Read.

 

It's a good read.

[InfiniteNow]

Use print preview.

Set the magnification.

Read.

 

It's a good read. :hyper:

 

Or... copy the text and paste it into the word processing software of your choice.

 

Or... select the text with your mouse so the colors appear reversed.

 

 

Or...

[Southtown]

Use print preview.

Set the magnification.

Read.

 

It's a good read.

Well, I guess I can figure something out, since you say it's good.

[Southtown]

HAHA! Trippy, and highly entertaining. I must thank you for suggesting it. Now I know what Lee Smolin meant about the extra dimensions in string/m being constrained beyond detection. String/m may make predictions someday after all.

ResearchChannel - The Trouble with Physics

The Trouble with Physics

Essentially, Calabi-Yau manifolds are shapes that satisfy the requirement of space for the six "unseen" spatial dimensions of string theory, which may be smaller than our currently observable lengths as they have not yet been detected.

--

Calabi-Yau manifold - Wikipedia, the free encyclopedia

Also, a couple questions: What would a hole in space consist of... matter? And didn't Hawking retract his Paradox?

[johnhuey]

That is interesting.

 

A quick search reveals that apparently the effect of Hawking Radiation, which is theorized to evaporate black holes - gets more and more pronounced as the amount of dark energy (and thus presumably the gravitational pressure differential between the event horizon and "normal" space) grows. This means that the black holes start to evaporate faster and faster, and eventually, like everything else, just vanish.

 

I guess, this means, that normally, space kind of "eats away" like an Alkaseltzer in water. Imagine the temperature differential of the water and the Alkaseltzer getting bigger, and larger and larger chunks of the Alkaseltzer coming off. I think.

 

NB: I pieced this together from reading reviews and abstracts of this Gonzales-Diaz article from around the internet.

 

My understanding is probably incomplete. YMMV.

 

TFS

 

Why would the Dark Energy increase the rate of Hawking Radiation? Looking at the equations in Wiki-pedia is seems to me that the rate of Hawking Radiation is determined only by the mass of the Black Hole. I can see where the Big Rip would 'clean up' the environment around a Black Hole so that no more mass was going in but I don't see how it would effect the amount of radiation coming out?

[johnhuey]

If we are dealing with the universe in the far far far future where all matter has been moved beyond the bounds of the observable universe and there is nothing left except one lone Black Hole does the idea of distance have any meaning anymore? If there is nothing on the outside of the event horizon does the Schwarzschild radius still mean anything?

 

Also, if inflation from Dark Energy means that empty space is expanding at an increasing rate and that this expansion is resisted by gravity then wouldn't the Big Rip and a Black Hole be in sort of a tug of war? But a tug of war where the Big Rip just keeps getting stronger and, once there is no more matter for the Black Hole to consume, the Black Hole stays essentially the same size. So, what would happen when the balance of strength shifts to the Big Rip?

[johnhuey]

Pardon me for heaping on questions but I been thinking hard on this idea all day and my mind keeps coming up with things and making connections that I don't know make any sense or not.

 

This is what my fevered intuition (unsupported by facts or theory) suggests would happen if the Big Rip hit a Black Hole and all the rest of the observable universe was empty. Due to the lack of any relative frame of reference the concepts of mass and distance really cease to have any meaning. The Gravitational Constant, in effect, ceases to have any meaning. The Big Rip, which by now represents an incredible amount of energy, essentially opens up the Black Hole like a birthday present. All the mass of the Black Hole plus all the energy from the Big Rip should combine to make one hell of a mess. What that mess is I don't know but I would guess it is another Big Bang.

 

Is this just a restatement of the Multi-verse idea or is this different?

 

My brain hurts.

[TheFaithfulStone]

Okay, we're getting into bits of physics that I don't understand now, but I'll take a stab.

 

A simple model of Hawking radiation is that when a virtual pair is produced very close to the event horizon, one falls in and one escapes. The one that falls in must have negative energy in order to conserve total energy, and thus the total energy of the black hole is reduced.

 

If normally (and innaccurately), the energy of the vacuum state is 0, then the particle production should yield a -1 energy state for the particle that goes into the black hole, and a +1 for the particle that comes out. It appears that the black hole has just emitted a particle. The black hole is now a particle down, the rest of the universe is a particle up, and energy is conserved.

 

OKAY, now for the Big Rip to occur, you need to have an increasing cosmological "constant." That is that Lambda needs to get bigger and bigger and bigger. (Or actually more and more pronounced, which means it needs to head negative. So is that smaller and smaller?)

 

Now, here is where I get pretty iffy. Black holes in expanding space time are represented by the Schwarzchild- De-Sitter Metric [math]\frac {\frac{1 - 2m} {r - \Lambda}} {r^2} = 0[/math] where [math]\Lambda[/math] is the cosmological "constant." So basically, as lambda get SMALLER (in the negative), the Scharwzchild radius for a black hole of a given mass increases. With a larger event horizon, there should be more particle events near it, which should result in a increased evaporation effect.

 

 

I think. You know what, that's about as smart as I am - I can't really take it any farther than that. I'm not absolutely positive I've even done that bit correctly.

 

TFS

[johnhuey]

Okay, we're getting into bits of physics that I don't understand now, but I'll take a stab.

 

A simple model of Hawking radiation is that when a virtual pair is produced very close to the event horizon, one falls in and one escapes. The one that falls in must have negative energy in order to conserve total energy, and thus the total energy of the black hole is reduced.

 

If normally (and innaccurately), the energy of the vacuum state is 0, then the particle production should yield a -1 energy state for the particle that goes into the black hole, and a +1 for the particle that comes out. It appears that the black hole has just emitted a particle. The black hole is now a particle down, the rest of the universe is a particle up, and energy is conserved.

 

OKAY, now for the Big Rip to occur, you need to have an increasing cosmological "constant." That is that Lambda needs to get bigger and bigger and bigger. (Or actually more and more pronounced, which means it needs to head negative. So is that smaller and smaller?)

 

Now, here is where I get pretty iffy. Black holes in expanding space time are represented by the Schwarzchild- De-Sitter Metric [math]\frac {\frac{1 - 2m} {r - \Lambda}} {r^2} = 0[/math] where [math]\Lambda[/math] is the cosmological "constant." So basically, as lambda get SMALLER (in the negative), the Scharwzchild radius for a black hole of a given mass increases. With a larger event horizon, there should be more particle events near it, which should result in a increased evaporation effect.

 

 

I think. You know what, that's about as smart as I am - I can't really take it any farther than that. I'm not absolutely positive I've even done that bit correctly.

 

TFS

 

Thanks for your reply. I'm confused by two things (well many things, but thats another story):

 

1.) Why are all the particles that fall into the Black Hole of negative energy? I would have thought that which particle falls and which escapes would be 50/50 random. Does the gravity of the Black Hole orient the particle production?

 

2.) If the pair of particles that are created are photons, one photon goes off in one direction and the other in the exact opposite so the energies of the two photons balance. But looking at any one of the photons independently is there any reason to tag one as positive energy and the other as negative?

 

I have other concerns about how the particles would interact within a Black Hole but I think I should address them in a Black Hole thread rather than this Big Rip thread.

[TheFaithfulStone]

Basically, picture a line, which is the event horizon.

 

Virtual Pair production will occasionally create a particle pair "straddling" that line. One of the particles will be within the event horizon, and one will be without. One of the particles will be sucked into the black hole, and the other will be able to go free.

 

Since they can't annihilate each other (as they normally do), and you can't add a particle to the universe since you'd be violating conservation of energy - to keep the energy equation balanced, the particle that the black hole captures must have negative energy. To the outside observer, it appears that the black hole just emitted a positive energy particle.

 

The particle that was just added to the universe is balanced by the particle that the black hole just lost. Effectively, the original particle is completely destroyed, but conservation is maintained.

 

Of course, there's a problem here, which is that black holes appear to completely destroy information. That's not really possible, and it doesn't make any sense. If you can figure out what happens to the information in a black hole conclusively, congrats, you've probably just made a career in theoretical astrophysics. :(

 

TFS

[johnhuey]

Basically, picture a line, which is the event horizon.

 

Virtual Pair production will occasionally create a particle pair "straddling" that line. One of the particles will be within the event horizon, and one will be without. One of the particles will be sucked into the black hole, and the other will be able to go free.

 

Since they can't annihilate each other (as they normally do), and you can't add a particle to the universe since you'd be violating conservation of energy - to keep the energy equation balanced, the particle that the black hole captures must have negative energy. To the outside observer, it appears that the black hole just emitted a positive energy particle.

 

The particle that was just added to the universe is balanced by the particle that the black hole just lost. Effectively, the original particle is completely destroyed, but conservation is maintained.

 

Of course, there's a problem here, which is that black holes appear to completely destroy information. That's not really possible, and it doesn't make any sense. If you can figure out what happens to the information in a black hole conclusively, congrats, you've probably just made a career in theoretical astrophysics. ;)

 

TFS

 

I'm really beginning to feel like one of your inquisitive idiots from your tag line. I read your explanation and still didn't understand, then I thought about it and thought I did understand. Now, I'm back to not understanding.

 

Let me explain my thinking on the conservation of energy from the particle pair and perhaps you can tell me where I go astray. Think of the conservation laws as a double entry accounting system: for every credit in one account of the system there is an equal debit entry(s) in a different account. However, when you look at any one of the accounts separately what you see are just positive numbers (typically). The negating of the entries is inherent in the math of the system (the definition of the account) not in the sign of the value in the ledger. So, following this analogy, then a black hole is composed of mass and energy that came from the Universe (say the credit side) so when the Hawking radiation makes a credit back to the Universe account it has to make a debit to the black hole account to balance. In side the black hole the debit then cancels with an earlier credit - hence the loss.

 

So, I guess my question then becomes what is the mechanism that the black hole uses to determine that the new particle is a debit instead of a credit?