Univers Inside a black hole

[Edgard Neuman]

hi,

 

I read that there's evidences indicating that black hole could host universes.
I have some idea about how it could be, inspired by bending of space-time

- the radial dimension from our point of view would become the time line of the inner univers
- the surface dimension would be the holographic (see the holographic theory) version of the content of the inner univers.

My idea is that since relativity tells us that something going at the speed of light should apear to us frozen in time, and since the general relativity tells that what is inside the black hole horizon seems to us going at that speed, the inner univers should be frozen in time. So the space-time content of the univers should appear to us like a story in a DVD. In a way time dimension would become a space component in ours (like the written data stream line of the DVD is a dimension)
It's also a good idea of the next limit of the univers : since we understand that space time is a "whole", everything we could possibly imagine "outside" would be localisable in it, except in the futur (which would be outside of our own black hole container).

What do you think about it ?

[ajb]

I read that there's evidences indicating that black hole could host universes.

Can you tell us what evidence so we have a better idea if what you are talking about?

 

It is possible for black hole that are large enough that the tidal forces are not too strong and that planets could be on stable orbits inside the horizon.

 

Also, of sorts our Universe is inside a black hole, that is we live inside a Hubble horizon!

[SamBridge]

Also, of sorts our Universe is inside a black hole, that is we live inside a Hubble horizon!

How come we haven't actually seen galaxies moving at near or past the speed of light or disappearing into going past the speed of light at 13.8 billion light years away if space is expanding faster than light after the hubble volume? And so how is the observable universe exceeding the hubble volume?

Edited April 19, 2014 by SamBridge

[ajb]

There is some slightly different notions at play here.

 

So if we consider the so called particle horizon which is the largest comoving distance from which light could have reached us in a given specific time, and we set that time to be the age of the Universe (forget surface of last scattering etc) then we get 14.3Gpc, which is the radius of our Observable Universe. This changes as we wait, we see more and more as light had more time to reach us.

 

The true event horizon would be defined as the largest comoving distance from which light could ever reach us. If the Universe just expands for ever then this distance would be infinite.

 

The third notion may answer some of your questions. In an accelerating universe, which we seem to live in there is also a de Sitter horizon. There are events that are truly unobservable to us. Recall that an external observer can never actually see something pass the event horizon of a black hole due to the red shift and time dilation effects. The external observer only sees the object get fainter and fainter but never actually disappear. Even if the object sends some special signal at the point he crosses the event horizon the external observer will never see this.

 

The same thing can happen in an accelerating Universe and I think this is why we have never really seen these objects disappear. They would be too faint to observe anyway and they would never actually totally disappear.

[SamBridge]

There is some slightly different notions at play here.

 

So if we consider the so called particle horizon which is the largest comoving distance from which light could have reached us in a given specific time, and we set that time to be the age of the Universe (forget surface of last scattering etc) then we get 14.3Gpc, which is the radius of our Observable Universe. This changes as we wait, we see more and more as light had more time to reach us.

 

The true event horizon would be defined as the largest comoving distance from which light could ever reach us. If the Universe just expands for ever then this distance would be infinite.

 

The third notion may answer some of your questions. In an accelerating universe, which we seem to live in there is also a de Sitter horizon. There are events that are truly unobservable to us. Recall that an external observer can never actually see something pass the event horizon of a black hole due to the red shift and time dilation effects. The external observer only sees the object get fainter and fainter but never actually disappear. Even if the object sends some special signal at the point he crosses the event horizon the external observer will never see this.

 

The same thing can happen in an accelerating Universe and I think this is why we have never really seen these objects disappear. They would be too faint to observe anyway and they would never actually totally disappear.

But this is somewhat different than a black hole because the gravitational pull of a non-rotating black hole doesn't cause things to accelerate past the speed of light, they accelerate space-time differently. At a certain distance from us, there should theoretically be an acceleration where space accelerates faster than light and thus photons can never reach us from that distance away, but this is not true of black holes, there is merely a distance where time dilation becomes so extreme it may appear to stop from an outside frame or 4-D curvature becomes enough that light waves can't travel outward.

But, if we teleported to that point that distance away where the expansion of space didn't permit photons to reach Earth, we would see the same thing happen to Earth where it started disappearing as it got further away, even though we know Earth isn't being ripped apart or traveling backwards in time from super-luminal travel. I mean of course we'd say the Earth is the center of the universe, that's the point where we'd spherically observe everything from, otherwise I also see no evidence to suggest the big bang happened as a spherical explosion few miles away from my house, and the same effects we observe from Earth should happen from any other point in the observable universe.

 

The third notion may answer some of your questions. In an accelerating universe, which we seem to live in there is also a de Sitter horizon. There are events that are truly unobservable to us. Recall that an external observer can never actually see something pass the event horizon of a black hole due to the red shift and time dilation effects. The external observer only sees the object get fainter and fainter but never actually disappear. Even if the object sends some special signal at the point he crosses the event horizon the external observer will never see this.

I thought being frozen was an old model with Swarchild mechanics and now we actually have accurate models than can model particles as they travel past the apparent horizon of a black hole. Red-shifting makes sense, but it doesn't really make physical sense that we'd see a physical object stuck at the horizon, because if they did stay frozen, we should never measure the black hole gaining mass and growing a horizon, but since it did, its event horizon would extend engulf a previously un-engulfed point.

Edited April 19, 2014 by SamBridge

[ACG52]

 

 

How come we haven't actually seen galaxies moving at near or past the speed of light or disappearing into going past the speed of light at 13.8 billion light years away if space is expanding faster than light after the hubble volume?

Because the furthest we've been able to see is 13.3 billion lys.

[SamBridge]

Because the furthest we've been able to see is 13.3 billion lys.

And at 13.3 it doesn't look like galaxies are almost traveling near the speed of light? And what about this one? http://www.telegraph.co.uk/science/space/10400568/Furthest-known-galaxy-found.html

And, if things disappear after 13.8 billion years or whenever the hubble volume is, how are we suppose to view anything resembling a big bang? If we're really the center of the universe why don't we just look for remnants of the biggest black hole ever our solar system? But we don't actually model it like that, what it models like is anywhere we go, we observe things expanding away in a sphere, and that's probably because the big bang wasn't an "explosion" so much as a creation of space.

Edited April 19, 2014 by SamBridge

[ACG52]

And at 13.3 it doesn't look like galaxies are almost traveling near the speed of light?

It does. Why would you think it doesn't. The fastest observed galaxy is receding at 0.9880532 c.

[SamBridge]

It does. Why would you think it doesn't. The fastest observed galaxy is receding at 0.9880532 c.

Well we're trying to get a look at the early universe, but if space is expending away from us faster than light at the distance where we say we can see the early universe, no matter where we look from we can't get a visual confirmation of it, so how else are we suppose to prove it? If we travel 13.8 billion light years to where we think we can see the early universe, we just see the same effects on our previous position and a bigger observable universe, unless for some weird reason there just happens to be a line that somehow has nothingness outside of it and somehow Earth actually is the literal center of the universe. I just don't understand how scientists are eager to look at the early universe and act like we proved what happened with the big bang when according to our own models there can't be a physical way to prove it.

Edited April 19, 2014 by SamBridge

[ACG52]

 

 

say we can see the early universe, no matter where we look from we can't get a visual confirmation of it, so how else are we suppose to prove it?

Well, this galaxy is at a distance of 13.3 billion lys. It doesn't get much earlier than that. And it's visual.

[md65536]

I agree with the idea. My own ideas and science news blurbs I've read seem to fit well, though not all of my own ideas make sense.

 

My idea is that since relativity tells us that something going at the speed of light should apear to us frozen in time, and since the general relativity tells that what is inside the black hole horizon seems to us going at that speed, the inner univers should be frozen in time.

Yes, black holes were once called "frozen stars" because time at the Schwarzschild radius is infinitely dilated, and light that is directed outward doesn't move in our coordinates. However, locally, to an inertial observer that light is traveling outward at the usual speed of light. If I understand that correctly it means that a black hole that is roughly fixed-size in our coordinates, can be expanding at the speed of light to an observer who enters, and maybe even faster to observers closer to the center. This is similar to how we measure the size of our universe. That alone suggests that from the inside, the observable size of the black hole is the same as that of their observable universe. Edited April 19, 2014 by md65536

[SamBridge]

Well, this galaxy is at a distance of 13.3 billion lys. It doesn't get much earlier than that. And it's visual.

The article I posted said over 13.7 billion years, but we still see no giant explosion or even incredible density, all we see are things fading away. If we have a telescope that can see 15 billion years, are we ever going to see an almost infinitely dense object that is exploding or any sort of spontaneous creation of matter, energy and space or even quark-gluon plasma? It doesn't seem like we will from any frame of reference.

 

I agree with the idea. My own ideas and science news blurbs I've read seem to fit well, though not all of my own ideas make sense.

Yes, black holes were once called "frozen stars" because time at the Schwarzschild radius is infinitely dilated, and light that is directed outward doesn't move in our coordinates. However, locally, to an inertial observer that light is traveling outward at the usual speed of light. If I understand that correctly it means that a black hole that is roughly fixed-size in our coordinates, can be expanding at the speed of light to an observer who enters, and maybe even faster to observers closer to the center. This is similar to how we measure the size of our universe. That alone suggests that from the inside, the observable size of the black hole is the same as that of their observable universe.

Well we don't know for sure what actually happens "at" the speed of light, tachyon physics suggests it doesn't matter much what's before or after the speed of light and that time may count in a different direction, just at the speed itself is what matters and not 100% before it because you still get a division by zero. Maybe there is some kind of infinite time dilation, but I don't think we'd actually measure it as such, we'd see them only indefinitely approach being frozen and red-shifted before some other variable we forgot to consider like event horizon growth swallows them. As far as I know, if you only consider classical relativity, gravity only propagates at the speed of light, so a change in the event horizon would otherwise never happen faster than light, but we also model black holes as changing in size from outside inertial frames because we need to in order to explain how black holes in the centers of galaxies got to be so big and also Hawking Radiation says they evaporate which scientists are now attempting to use in some fashion to explain how matter and energy we see came from a super-duper huge black hole-like object that was evaporating to create a big bang.

Instead of saying "infinitely dilated" I would just say 'indefinitely" dilated and that something redshifts enough that we can't see it anymore, but as you said a particle itself should measure everything normally and pass through the event horizon like nothing happened, except when they look back up, they will see the universe very differently.

 

On the interior of a black hole, if you look at the "ball on a net" model, do you think the curvature of space-time ever exceeds 90 degrees? In the ergoshere of a rotating black hole which is a lot more closely related to the geometry of space-expansion than a gravity field, it's a different type of curvature that does permit superluminal travel, one that apparently doesn't happen asymptotically like gravity does. If you have a really massive star, there is no amount of time that you can spend free-falling towards it that will get you past the speed of light, and that's due to the fact that the curvature of space caused by non-rotating gravitational fields is hyperbolic in nature.

Inside a black hole, we still don't know exactly how time would act. Why wouldn't someone in a black just observe the entirety of all events in the outside universe happening all at once if the rest of the universe is counting time that much faster? If you traveled at the speed of light, you could speculate a similar thing happens since you travel indefinite distance without time passing, supposedly, it's like saying finite velocity = infinite velocity, it's weird, it doesn't make sense, there's still some things to work out.

Edited April 19, 2014 by SamBridge

[ACG52]

 

 

The article I posted said over 13.7 billion years, but we still see no giant explosion or even incredible density, all we see are things fading away.

That's because there's no light. Photons were not free to travel until 380,000 years after the BB. We see those as the CMB. From then for another 400 million years, there were no light sources. So we can see the CMB, but that's as far back as light can take us.

 

BTW, there was no giant explosion.

[SamBridge]

That's because there's no light. Photons were not free to travel until 380,000 years after the BB. We see those as the CMB. From then for another 400 million years, there were no light sources. So we can see the CMB, but that's as far back as light can take us.

I guess there were other particles though even if there weren't photons which I hadn't considered before, I guess it could be possible to see something closely resembling an ultra-high density of a particular particle, but otherwise you're right, so I don't see how we're suppose to confirm everything else about what's prior to that. You have predictions like "a few nonseconds after the big bang..." but there's no way to know that, so what are we suppose to do to actually confirm anything?

 

BTW, there was no giant explosion.

:facepalm:

Edited April 20, 2014 by SamBridge

[ACG52]

 

 

You have predictions like "a few nonseconds after the big bang..." but there's no way to know that, so what are we suppose to do to actually confirm anything?

We look at the predictions made by the theory, and compare them with the actual universe. If they match, that's evidence that the theory is correct. The theory predicts a certain amount of primordial helium was created, and that matches what has been observed. The theory predicts the black body spectrum of the CMB, and that matches exactly with what is observed.

 

You seem to take the position that if emitted photons don't enter your eye, there's no way to confirm things.

[SamBridge]

 

You seem to take the position that if emitted photons don't enter your eye, there's no way to confirm things.

Well the closer we get to the actual moment of the big band, the less clear things become because we have less information and we also approach seemingly seemingly paradoxical or nonsensical consequences. We observed large amounts of hydrogen and helium in the universe first, then tried to explain it. But, we don't see a bunch of multiverses, we don't see a physical boundary past which we can say there's nothingness, we can't even really agree on how many dimensions there are, we don't even see dark energy. But, there were other particles weren't there besides photons weren't there, I wonder if that would amount to anything.

Edited April 20, 2014 by SamBridge

[ACG52]

Well the closer we get to the actual moment of the big band, the less clear things become because we have less information and we also approach seemingly seemingly paradoxical or nonsensical consequences. We observed large amounts of hydrogen and helium in the universe first, then tried to explain it. But, we don't see a bunch of multiverses, we don't see a boundary or any sort of nothingness, we can't even really agree on how many dimensions there are, we don't even see dark energy. But, there were other particles weren't there, might be worth looking into. Wonder if a cosmic dark-matter particle background would amount to anything, it makes up a lot of the apparent universe.

No, the mathematics of the BB theory predicted the amounts of primordial helium and hydrogen. Observation confirmed the prediction. BB theory doesn't say anything about multiverse, that's something else. Your statement 'we don't even see dark energy' makes perfect sense, since dark energy doesn't emit photons. There's LOTS of things that we can't see. Does that mean they don't exist?

[SamBridge]

No, the mathematics of the BB theory predicted the amounts of primordial helium and hydrogen. Observation confirmed the prediction.

But we observed through spectral analysis that most of what we see is hydrogen first, we didn't make a conjecture on the composition of the universe before we even looked at it.

 

BB theory doesn't say anything about multiverse, that's something else.

Older BB theories don't, but, some theories combine the big bang with a vacuum fluctuation model in order to explain where it may have come from which suggests different universes expand differently and the ultimate effect of dark energy is variable because there were different fluctuations in other universes creating different amounts of matter, some with enough mass density to ultimately overcome the dark energy expansion.

 

There's LOTS of things that we can't see. Does that mean they don't exist?

Did you read what I said? I was suggesting the use of dark energy like a map as we did with the cosmic microwave background if we ever figured out how to measure it. There still may have been other particles that were free to travel which is actually a good point. Another thing that still doesn't remain clear is the actual total mass and energy in the universe. We can say "there were a billion photons for every nucleon" during the photon epoch, but it doesn't seem like we have anything to suggest any sort of limit or size or content of the entirety of observable matter and space, even with a Hubble volume we can say that any inertial frame would see the same effects of expansion of equal distances away. And how exactly does every point expand from every other point in purely flat space? It would make sense in a curved universe, but apparently we don't see the triangulation that would suggest a curved universe. Although I guess there is a sort of 5th dimension of space that's being mathematically explored and there is more than one way space can be bent, but I'm not sure exactly how it would happen in the case of expanding from every point in flat space.

 

Photons were not free to travel until 380,000 years after the BB.

If photons were so dominant in a period before 380,000 years, why would so few be visible? Matter couldn't have been that dense 380,000 years after the BB, and we can't say the entire universe had a finite size.

 

And just as a different segue even though I already said it, it still seems weird. If I'm 100% far enough away that space expands faster than light, the photons at that distance will never reach me, but then I move a few light years in a particular direction and now the previously invisible photons in that direction will now eventually reach me at some point in time. I guess it's weird because, couldn't I just move a few light years towards something so that it has the potential to reach me, and then wait until it's potential to reach a particular point has exceeded my original position and then move back to my original position to see those photons that were originally invisible from that position? Something about that doesn't seem right.

Edited April 20, 2014 by SamBridge

[ajb]

But this is somewhat different than a black hole because the gravitational pull of a non-rotating black hole doesn't cause things to accelerate past the speed of light, they accelerate space-time differently.

I think all we need is an acceleration to have horizons like that.

[ACG52]

 

 

If photons were so dominant in a period before 380,000 years, why would so few be visible?

Because prior to that, the universe was filled with free electrons which absorbed the photons. When the temp of the universe dropped sufficiently to allow electrons to join with protons, the photons were free to travel.They've been traveling and being absorbed for the last 13+ billion years, so there aren't that many (comparatively) left.

[MigL]

Come on Sam.

 

"Did you read what I said? I was suggesting the use of dark energy like a map" ???

 

Dark energy is the equivalent of vacuum energy/cosmological constant, or it acts exactly like it. How would you map that ?

 

"If photons were so dominant in a period before 380,000 years, why would so few be visible" ???

 

They ALL are, but most are red shifted down to 2.7 deg K. Do you know what the CMBR is ?

[SamBridge]

 

They ALL are, but most are red shifted down to 2.7 deg K. Do you know what the CMBR is ?

Read what he said.

That's because there's no light. Photons were not free to travel until 380,000 years after the BB.

Take it up with him. And if they're redshifted beyond a certain point anyway, we can't see them. Are you trying to imply that if we had a good enough telescope that could see the faintest possible photons we'd see space pico-seconds after the big bang?

 

 

Dark energy is the equivalent of vacuum energy/cosmological constant, or it acts exactly like it. How would you map that ?

Dark energy is still creates measurable effects like negative pressure which can possibly vary in small fluctuations anyway, and it could exist in quantized amounts and must have some particle that mediates its force.

Edited April 21, 2014 by SamBridge

[ACG52]

 

 

Are you trying to imply that if we had a good enough telescope that could see the faintest possible photons we'd see space nano-seconds after the big bang?

No I'm telling you that the farthest back we can look is 377,000 years after the BB started. That's what we see when we look at the CMB.

Edited April 21, 2014 by ACG52

[SamBridge]

No I'm telling you that the farthest back we can look is 377,000 years after the BB started.

I was talking to the other guy who seems to say otherwise.

But anyway,

Because prior to that, the universe was filled with free electrons which absorbed the photons. When the temp of the universe dropped sufficiently to allow electrons to join with protons, the photons were free to travel.They've been traveling and being absorbed for the last 13+ billion years, so there aren't that many (comparatively) left.

But despite the universe being filled with fermions, there was still a billion photons per fermion, even with a universe that had a density of the core of a star, the photons from previous times should still be able to escape as they actually do in stars which means the CMB should give us information from before 380,000 years, but only reflect the "shape" of the universe from 380,000 years ago, which is exactly what it does, I'm just not so sure we can't see that far back entirely since our best telescope only sees 700,000,000 years after the BB.

Edited April 21, 2014 by SamBridge

[ACG52]

 

 

But despite the universe being filled with fermions, there was still a billion photons per fermion, even with a universe that had a density of the core of a star, the photons from previous times should still be able to escape as they actually do in stars which means the CMB should give us information from before 380,000 years, but only reflect the "shape" of the universe from 380,000 years ago, which is exactly what it does, I'm just not so sure we can't see that far back entirely since our best telescope only sees 700,000,000 years after the BB.

Here, maybe reading something will help clear it up for you.

 

http://en.wikipedia.org/wiki/Recombination_(cosmology)