Naked Science Forum
On the Lighter Side => New Theories => Topic started by: OokieWonderslug on 02/06/2022 18:56:35
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Since it has been postulated that black holes form "universes" inside them that forces the question of what happens to things when they fall into the black hole. Logic says if such things exist (the universes) where space and time are reversed then any matter falling into the black hole could not retain any of it's information. Scale would not be compatible. One of our atoms might be as large as a planet in another universe. So my theory is that anything that falls into a black hole creates dark energy that would hasten the expansion of the universe it falls into. So what we observe in our universe is fueled by matter falling in the black hole that "owns" our universe. Anyone else see this as obvious? Or am I way off track? It seems pretty self evident to me. If it's wrong or impossible, how is it like that?
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Since it has been postulated that black holes form "universes" inside them that forces the question of what happens to things when they fall into the black hole.
I don't know any theory that postulates that black holes form universes.
Logic says if such things exist (the universes) where space and time are reversed then any matter falling into the black hole could not retain any of it's information.
Why would space and time be reversed? How is space reversed?
Scale would not be compatible. One of our atoms might be as large as a planet in another universe. So my theory is that anything that falls into a black hole creates dark energy that would hasten the expansion of the universe it falls into. So what we observe in our universe is fueled by matter falling in the black hole that "owns" our universe.
Black holes do not repel things so they would not increase expansion they would tend to inhibit expansion.
Anyone else see this as obvious? Or am I way off track? It seems pretty self evident to me. If it's wrong or impossible, how is it like that?
This is not obvious and I think you are a bit off track here.
There is a lot of great information about black holes on the internet and unfortunately there is a lot of misinformation about black holes. If you are interested, you could start by checking out black holes on the NASA site.
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"I don't know any theory that postulates that black holes form universes."
It is mentioned on PBS Space Time every so often. If you can visualize a star collapsing into a black hole that singularity is akin to a hole in this dimension of space. The gravity a black hole has is a shadow of the mass on the other side of it. The words don't really match what I am trying to relate. Space and time reverse for basically the same reason an image in a pinhole camera is flipped.
"Black holes do not repel things so they would not increase expansion they would tend to inhibit expansion."
In this universe. The expansion of our space time would be related to whatever matter was falling in to a black hole in another dimension. THE black hole that's creation was our "big bang". It still exists in whatever dimension it was formed in. And when it is eating matter that matter fuels our universe's expansion. We can deduce that our 14 billion years and near infinite space would be a place of infinite time and very little space. Universes are like a froth of foam on an infinitely recursive plane.
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If you can visualize a star collapsing into a black hole that singularity is akin to a hole in this dimension of space. The gravity a black hole has is a shadow of the mass on the other side of it. The words don't really match what I am trying to relate.
Again I have seen no theory of black holes that alludes to something like this. Do you have a source for this?
Space and time reverse for basically the same reason an image in a pinhole camera is flipped.
That doesn't make sense to me. There is nothing about a black hole that is like a pinhole camera.
In this universe. The expansion of our space time would be related to whatever matter was falling in to a black hole in another dimension.
What do you mean by a another dimension?
THE black hole that's creation was our "big bang".
Our universe did not come from a black hole.
It still exists in whatever dimension it was formed in.
I think you made that up, there is no theory that says that.
We can deduce that our 14 billion years and near infinite space would be a place of infinite time and very little space. Universes are like a froth of foam on an infinitely recursive plane.
I'm not sure what you are trying to say here.
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Again I have seen no theory of black holes that alludes to something like this.
I think it might be an application of holographic principle (everything stuck on a 2D surface of event horizon), somehow defining a separate universe within. It doesn't address the fact that a universe that isn't closed (always new stuff falling in), isn't really a separate universe.
Space and time reverse for basically the same reason an image in a pinhole camera is flipped.
If one pictures a black hole in radial coordinates, the radial dimension (down) becomes a time dimension, and the old time dimension becomes an infinite spatial one. Hence the physical singularity not being a point in space, but rather a moment in time (a rude abrupt end of time).
Not to defend what's being asserted in this thread, but the rotation of the axes is very much a thing.
It still exists in whatever dimension it was formed in.
I think 'dimension' is being used in a different manner than geometry here, kind of like 'from beyoooonnnnd' (cue eerie music)
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Hi.
You've had some good answers or replies already but it's a fair set of ideas and I'm happy to discuss most things. I am, however, going to start by suggesting that there is less need to answer the questions you presented than you might have thought.
Since it has been postulated that black holes form "universes" inside them that forces the question of what happens to things when they fall into the black hole.
As @Halc suggested, there is a theory for a Holographic universe where all the information for a 3-dimensional space is contained on a 2-dimensional surface. The most interesting situation is that the surface of a black hole can encode all the information about whatever has fallen into it. So it has been suggested that we (our universe) "might be" inside a black hole. There then "might be" other universes inside other black holes. It's all a "might be" kind of thing rather than a "this is how it is" type of thing.
So you asked "What happens to things when they fall into the black hole?" That question has some answers using conventional General relativity. General relativity is just one way of modelling the situation but it's about the best we have.
1. To an observer outside of the black hole (so that could be me on planet earth while watching something fall towards the black hole at the centre of our own galaxy), then it just never ever does reach the interior of the black hole. An infinite amount of time would have to pass for me before the object would have crossed the event horizon. The question is then irrelevant for me and my universe - it just never happens, no object goes beyond the event horizon of that black hole. This is often mentioned with the example of an object in free-fall toward the black hole but it's also true even if something is trying to get into the black hole faster than that. For example, you can fire a beam of light toward a black hole so that's heading toward the black hole at the speed of light (i.e. as fast as anything can go) but it will still take an infinite amount of time (for an observer outside the black hole) before that light crosses the event horizon.
2. We can take a different frame of reference (a LIF = a Local Inertial Frame, GR likes to emphasize that we can't take a frame of reference and expect it to behave properly like an inertial frame if we extend it too far). We could take the LIF that moves with the object so that it is always stationary in that local frame. Then the object can and does cross the event horizon in finite time in those co-ordinates. Once it crosses the event horizon it is causally disconnected from the space and time outside of the event horizon. To say it another way... it doesn't care what happens out there and there's nothing it can do to influence anything out there anyway. We (here in our universe) don't need to care anymore, it is in a region of spacetime that is disconnected from us. That doesn't quite answer your question but it just shows that it's only of interest to the object that crossed the event horizon, it's irrelevant to anyone outside the black hole. So it doesn't "force the question" as you said... it's a perfectly reasonable question but the answer to it need not affect us at all.
There's more that could be said but this post is already long enough. Black holes are weird and it's just important to note that things don't fall into them or through them in finite time for any outside observer. A simpler idea of stuff falling into our universe is the idea of a "white hole", which is discussed in various places if you want to look into it. Stuff from such a white hole would just be all the stuff that is in our universe now... So that will be ordinary matter just as much as the more exotic stuff that might be also be in here (like dark matter or dark energy).
Dark energy may or may not be "stuff", it is just gravity behaving oddly and for which there is no established explanation. It could be "stuff" that is causing this but it could be just an indication that our models of gravity need fixing. The currently favoured theory of cosmology is called the Lambda Cold Dark Matter (ΛCDM) model where dark energy is just considered as a non-zero cosmological constant that should be included in the Einstein Field Equations (it's a modification to the original Einstein theory rather than being some "stuff" that exists in the universe).
Best Wishes.
*LATE EDITING: See later posts. The strikethrough removes the implication that the interior is causally disconnected from the exterior.
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Very interesting, eternal student. In our frame of reference we expect a black hole "evaporate" via hawking radiation even if it takes tens of billions of years. So an object that reaches the event will see time in our external reference frame race forward at infinite speed and the black hole will disappear?
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Then the object can and does cross the event horizon in finite time in those co-ordinates. Once it crosses the event horizon it is causally disconnected from the space and time outside of the event horizon. To say it another way... it doesn't care what happens out there and there's nothing it can do to influence anything out there anyway.
This is not true. Nothing weird happens upon crossing the event horizon, and you can still receive messages ("It's a boy!") from your pregnant wife you left behind. But you can't reply, so it's a one-way disconnection.
So the view of falling in (they have videos of it) is that once you cross the photo-sphere, there is a region of sky from which light doesn't come from distant objects. You can still see everything around you, but the distant universe appears in a finite swath of your field of view, which just gets narrower and narrower until it reaches a point, and then time ends. The event horizon is crossed well before that point with no noteworthy local changes.
In our frame of reference we expect a black hole "evaporate" via hawking radiation even if it takes tens of billions of years.
A lot longer than that. A small one might take 1067 years, and more for a larger one. In 10 billion years, all black holes will be larger, not smaller than they are now.
So an object that reaches the event will see time in our external reference frame race forward at infinite speed and the black hole will disappear?
No, nothing unusual happens. The event horizon is just a coordinate singularity and one can watch the world outside (redshifted, so slowed down, not speeded up) as one falls in. There is a finite time on the outside beyond with a message will not reach the infalling observer before his time is up. So you might learn that it's a boy, but you'll not witness his first birthday.
I will say that if you fall into a black hole, you'd want to pick a big one since the tidal forces of a little one would kill you long before you reached the event horizon. Even in a big one, the tides will eventually be fatal, pulling you apart before time ends.
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Hi.
so it's a one-way disconnection.
Yes. (I did phrase it all badly and it does read like something else). The outside of the event horzon is causally disconnected from the inside but not vice versa.
Also, if those videos are publically accessible, I'd be interested in seeing them.
Best Wishes.
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Halc, if we observe an object approach an event horizon(from a safe distance) we will see it's progress progressively slow down and it's internal clock will also slow by an equal degree. Now supposing we find that a one second interval in the objects clock occurs in one year of our time. Therefore in one second of the object's frame of reference the external universe will be seen to have advanced one year, ie speeded up. Or maybe i'm just stooped.
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Also, if those videos are publically accessible, I'd be interested in seeing them.
This 40 second vid is nice, but it adds grid lines to what you see so you can really tell when you cross the EH. I saw the same video with the same simulation twice, once with and without the grid lines. Can't find it now. But this one is nice because it also shows where you are in coordinate space, the little graphic on the lower left. The observer is spiraling in, not falling straight down.
Now supposing we find that a one second interval in the objects clock occurs in one year of our time. Therefore in one second of the object's frame of reference the external universe will be seen to have advanced one year, ie speeded up.
You're thinking in absolute time terms, so no. The rest of the universe is moving quickly away from you, so their time appears to slow relative to you, mostly due to Doppler effect. During that one second (and the one after it after you have crossed in), you might see perhaps a third of a second happen on Earth. Just guessing.
What is closer to your suggestion is an observer not in freefall but at rest in the coordinate frame. Let's say you instead sit at the surface of a neutron star. Despite that being quite fatal, you'd see the universe speed up from that vantage. Likewise, if one were to actually hover just outside the event horizon rather than be falling, it would be even more fatal, but you'd see the universe progress arbitrarily fast, perhaps at a year per second, depending on the altitude at which you hover. The acceleration you'd need to stay there is arbitrarily high, which is why it would be fatal.
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Also, if those videos are publically accessible, I'd be interested in seeing them.
You might also be interested in the rest of the site https://jila.colorado.edu/~ajsh/bh/schwp.html#geometry
I thought I had posted these in a previous discussion with @geordief but it looks as though the post was truncated without giving the full answer.
I can vouch for the authenticity of these simulations having been involved on proof checking some of the original work, but funding has been diverted to other projects rather than extending to cover other scenarios.