There is a fascinating PBS Space Time video[1] about black holes that questions the very existence of whatever is "inside" a black hole.
They point out that as you approach a black hole, your proper time is advancing slower and slower when compared to an observer located far away from the black hole (like us, on Earth). That means that from the point of view of this far observer, nothing happens inside a black hole until an infinite amount of time. In other words, what is inside a black hole is separated from us not by a space-like frontier, but a time-like one. Events behind the event horizon are postponed to "the end of times".
Does it even make sense to say that those events exist, then? Are they any more real than fairy tales or mathematical equations? If not, we can make any speculation we want, including the existence of alien civilizations.
Here's something I've wondered about black holes, related to what's inside. Simplistically, there must be mass inside, i.e., every black hole has a mass that can somehow be measured, e.g., by orbital velocities of satellites. And the mass-energy has to equal the mass-energy that has fallen in. So far so good.
But the stuff that falls in is not purely described by its mass. It also has angular momentum, electrical charge, maybe a few other quantities such as charm and strangeness (speculating here). So the black hole must have a net angular momentum, electrical charge, charm, and strangeness. Electrical charge could be measured by holding an electrometer next to the black hole. And so forth.
So far I've described 5 quantities that "describe" a black hole. So my question is: How many more are there? What's the total number of numbers that accompany a particle as it gets sucked in?
Suppose it's a small number, like 11. Does that place an upper limit on the information content of a black hole, and hence the possibility of describing a "civilization" inside it?
That's the thing that never made sense to me about the black holes. The closer you are to the event horizon, the faster the time passes for the universe around you. So reaching the event horizon should take infinite amount of the "outside time", so right before you reach the horizon, you should see the whole future of the universe, including its end, if there's any.
off-topic a bit: does anyone have suggestions for paths for the layperson toward being able to reason and intuit about this stuff at one level beyond pop physics claptrap?
I have heard "the theoretical minimum" suggested in the past, but I haven't heard from anyone who has actually used it to go from zero to say, general relativity, only people who think it sounds good. It also seems like a steep investment -- I just want to have a decent enough grasp to separate sense from nonsense and hold a picture in my mind.
One related thing I have wished existed was a good place to ask questions about and discuss topics like this while learning them, but it seems like in theoretical physics, everyone (including myself) has an infinite number of different stupid questions and misconceptions, to the point that we drown each other out, and answers to our questions often have little cross-applicability.
No it doesn’t make sense. That explanation is privledging remote observers frames of reference to “explain” what happens in another frame of reference. That’s a violation of our modern understanding of physics.
I’ve wondered this too but I just had a thought. I ended up asking myself why any black hole is ever bigger than critical mass if this is true.
Take a black hole that’s been slurping matter in and it’s all at the event horizon because as you say, it takes forever to cross. But as that mass builds and builds doesn’t the event horizon move? Take the scene to the limit. Say a black hole never absorbs anything. The amount of mass parked just above the horizon becomes so great that another black hole forms. Now you have two overlapping horizons, which can’t stay that way. What really happens is that the density of mass inside the radius near the black hole is sufficient to be a black hole of a larger diameter and then it just... is.
I think that what this means is that you never get to the event horizon, but the horizon comes to you.
I imagine this as time asymptotically slowing as you approach the singularity so that the singularity is forever stuck at the time of the supernova explosion that gave birth to it. You can never reach it because you and your movements too, slow down the closer you get. Is that correct?
If you've not come across Lee Smolin's (speculative) writing on the Fecund Universes theory, you'll probably also love it. Don't have any links as I've only read about it in one of his books, but it's a fascinating idea.
Our own past (say, 1974, for example) is also “separated from us not by a space-like frontier, but a time-like one“. Would you say that the past is not real?
not an physicist, but from the point of view of the thing going on the black whole, time still goes on smoothly. My understanding is that the inside of the black whole becomes like a new universe, effectively cut from the previous one from the perspective of causality
This strikes me as an issue between understanding these events from the point of view of an external observer, and a test particle or person falling into the hole. From the POV of the observer, your statements are largely accurate, for certain types of universes. For the test particle, there is no freeze frame, all proceeds normally.
The key is the Relative in Relativity.
Truthfully, there is no clear answer as to what a black hole has for an interior, or if it really has one. Holographic theorists would argue that the event horizon is the black hole, String theorists would argue that there is an interior, but no singularity. We just don’t know.
Between reality and maths, the maths are the more fundamental thing that is used to explain reality. What you call reality is just some circumstances that your brain got used to.
> Events behind the event horizon are postponed to "the end of times".
Thank you. To me, this has been obvious since I learned about the time slowing required by GR. Since then, I was unable to understand why people are talking about things "falling into" black holes. (There's an episode of SG-1 where a team is trapped by a black hole, and times keep slowing, but they never realize that this means that team WILL NEVER DIE.)
Reminds me a bit of the old short story The Crystal Spheres. In that universe, once a civilization had attained a certain level of advancement, they intentionally migrated to a black hole to await the arrival of others (the idea being that all advanced civilizations in the universe were separated by so much time, that they suffered from a sort of loneliness).
There's another book whose name is on the tip of my tongue that has a similar premise, except the planet instead of the entire system is encased in a sort of time-dilation field. Naturally, humanity thinks it's an attack.
Wonder if they also explored the possibility that we are in a black hole and the universe structure is recursive.
Maybe the background radiation is the part of the hawking radiation that falls inward. And we perceive it infinite but it’s the dilatated space between the hevent horizon and the naked singularity at the center. And the big bang was the supernova that left the black hole.
I've always liked toying with the idea (in my own head, not an astrophysicist) that space is cyclical, or in your words, recursive.
I love animations where it zooms out farther and farther into space, until it gets to the point where galaxies start to resemble molecular structures.
And then of course The Simpson's did a couch gag where exactly this happens and they zoom out and out into space until it finally zooms out of Homer's own head.
That's a very interesting idea! Although, if the cosmic background radiation is the hawking radiation falling back toward the event horizon, where is the residual radiation left behind by the supernova (because in the traditional interpretation, CMB the afterglow of the big bang).
We are inside of infinite number of recursive black holes. We are inside infinite number of Homer heads. But we are too small to view whole picture even for level above.
We are in a black hole. The event horizon of the entire universe is on the same order as the observable universe. We are inside the black hole of the universe.
I don't think that's possible. Perhaps the singularity itself will survive a "Big Crunch", but I doubt anything between it and the event horizon will. And without the ability to survive the end of the universe, life is unlikely to emerge inside an orbit within a blackhole. Because of the time dilation, life will evolve there hundreds if not thousands of times slower compared to the rest of the universe. So the lifespan of the universe itself may be insufficient for life to form there.
But if the black hole can survive the big bang, therefore it can exist longer that rest of the universe so it seems to have plenty of time to evolve anything.
Fredric Pohl scifi fans might enjoy Hechee Rendesvous, which is near the end of the Gateway series. Somone finds a way to live inside both Kugelblitzen and black holes I think.
Definitely an almost amusing overlap between different senses of “singularity”.
Such civilizations might be like “simple germs”, their self-sustaining black hole vessels interacting and stirring things together; perhaps the cores of the most “interesting” galaxies are sentient, waiting for one femto-tech civ to arise from a trillion slime-ball planetoids — to make first Contact...
The more general possibility of “intersecting” reality at right angles has been taken up in a few additional works I can think of: in Count to Infinity and Excession.
> There was a second, unrelated paper that suggests that aliens can live inside black holes.
[ ... snip ... ]
> In theory, highly advanced aliens could live on such planets, being unobservable from outside while exploiting the high energies and large time dialtions available.
Wouldn't the aliens just need to wait for the black hole to evaporate in order to escape? We're talking a long time, but still possible? If it was planned just right, perhaps they could make it so they emerge in the new Universe.
Also, isn't the assumption that there is a "big crunch" (also a good name for a cereal if it doesn't exist)? We're not sure whether there is a big crunch or heat death? This still seems plausible whether there is a big crunch or heat death - either way a black hole may be the only way for a civilization to stay alive at "the end".
Being emitted as undifferentiated Hawking radiation, after the black hole has shrunk to microscopic size, and when it finaly ceases to exist doesn't sound like much of a happy ending.
If the universe expands in a big bang, collapses in a big crunch, and then expands in another big bang, then it’s not a different universe.
The black hole wouldn’t be older than the universe. The black hole is just older than the last, most recent big bang, and the big bang doesn’t explain anything anymore.
It’s disproven as an event of creation. The big bang just becomes different parlance for turtles all the way down.
what if our universe is expanding because there are other bubbles of universes that pull in all directions?
what if Buddha was right in that there are thousand fold universe systems each with their own unique civilizations?
If there are blackholes older than the universe itself, what if that suggested the universe was cyclical and that we may be in some gazillion-th iteration?
what if big bang was just a universe eventually being consumed by a monstrous blackhole that collapses itself?
What about the strange UFO occurences that pentagon acknowledged, are we getting visits from aliens within our universe or from another universe? Have they figured out how to travel between multi-verse, that is if you believe in it?
No proof, no way to find these answers but it really makes me wonder, especially when particles behave strangely like being coupled regardless of distance...but how could Buddha have known that blackholes existed?
>What about the strange UFO occurences that pentagon acknowledged, are we getting visits from aliens within our universe or from another universe?
The Pentagon has never acknowledged the existence of extraterrestrial craft, or of UFOs as being anything but hoaxes and misidentified, mundane phenomena.
>but how could Buddha have known that blackholes existed?
He didn't, any more than the Norse knew that wormholes existed when describing the Bifrost bridge or the World Tree. Reading modern scientific meaning into ancient religious ideas is a common way to attempt to validate religion, but doing so does a disservice both to the religion and to science.
The Buddha may have had many insights, but none of them involved the relationship between spacetime and gravity.
Yes there are. Answering such questions is why physicists are searching so hard for a unified micro/macro theory. Black holes are both quantum mechanical (at their singularities) and relativistic.
> how could Buddha have known that blackholes existed?
[+] [-] grondilu|8 years ago|reply
They point out that as you approach a black hole, your proper time is advancing slower and slower when compared to an observer located far away from the black hole (like us, on Earth). That means that from the point of view of this far observer, nothing happens inside a black hole until an infinite amount of time. In other words, what is inside a black hole is separated from us not by a space-like frontier, but a time-like one. Events behind the event horizon are postponed to "the end of times".
Does it even make sense to say that those events exist, then? Are they any more real than fairy tales or mathematical equations? If not, we can make any speculation we want, including the existence of alien civilizations.
1. https://www.youtube.com/watch?v=vNaEBbFbvcY
[+] [-] analog31|8 years ago|reply
But the stuff that falls in is not purely described by its mass. It also has angular momentum, electrical charge, maybe a few other quantities such as charm and strangeness (speculating here). So the black hole must have a net angular momentum, electrical charge, charm, and strangeness. Electrical charge could be measured by holding an electrometer next to the black hole. And so forth.
So far I've described 5 quantities that "describe" a black hole. So my question is: How many more are there? What's the total number of numbers that accompany a particle as it gets sucked in?
Suppose it's a small number, like 11. Does that place an upper limit on the information content of a black hole, and hence the possibility of describing a "civilization" inside it?
[+] [-] olegkikin|8 years ago|reply
So how do black holes gain any mass then?
[+] [-] wcarss|8 years ago|reply
I have heard "the theoretical minimum" suggested in the past, but I haven't heard from anyone who has actually used it to go from zero to say, general relativity, only people who think it sounds good. It also seems like a steep investment -- I just want to have a decent enough grasp to separate sense from nonsense and hold a picture in my mind.
One related thing I have wished existed was a good place to ask questions about and discuss topics like this while learning them, but it seems like in theoretical physics, everyone (including myself) has an infinite number of different stupid questions and misconceptions, to the point that we drown each other out, and answers to our questions often have little cross-applicability.
So, would love ideas for either!
[+] [-] pwaai|8 years ago|reply
This is mind blowing...shatters my misconception of blackholes....is there any more books on this?
[+] [-] garmaine|8 years ago|reply
[+] [-] hinkley|8 years ago|reply
Take a black hole that’s been slurping matter in and it’s all at the event horizon because as you say, it takes forever to cross. But as that mass builds and builds doesn’t the event horizon move? Take the scene to the limit. Say a black hole never absorbs anything. The amount of mass parked just above the horizon becomes so great that another black hole forms. Now you have two overlapping horizons, which can’t stay that way. What really happens is that the density of mass inside the radius near the black hole is sufficient to be a black hole of a larger diameter and then it just... is.
I think that what this means is that you never get to the event horizon, but the horizon comes to you.
[+] [-] hliyan|8 years ago|reply
[+] [-] teh_klev|8 years ago|reply
I also really need one of these:
https://store.dftba.com/collections/all/products/heat-death-...
[+] [-] gooseyard|8 years ago|reply
[+] [-] brianberns|8 years ago|reply
[+] [-] v_lisivka|8 years ago|reply
[+] [-] make3|8 years ago|reply
[+] [-] IntronExon|8 years ago|reply
The key is the Relative in Relativity.
Truthfully, there is no clear answer as to what a black hole has for an interior, or if it really has one. Holographic theorists would argue that the event horizon is the black hole, String theorists would argue that there is an interior, but no singularity. We just don’t know.
[+] [-] dustingetz|8 years ago|reply
[+] [-] mdpopescu|8 years ago|reply
Thank you. To me, this has been obvious since I learned about the time slowing required by GR. Since then, I was unable to understand why people are talking about things "falling into" black holes. (There's an episode of SG-1 where a team is trapped by a black hole, and times keep slowing, but they never realize that this means that team WILL NEVER DIE.)
[+] [-] jcadam|8 years ago|reply
https://en.wikipedia.org/wiki/The_Crystal_Spheres
[+] [-] pavel_lishin|8 years ago|reply
[+] [-] Flow|8 years ago|reply
A similar theme is in "Pushing Ice" by Alastair Reynolds.
Someone has built machines that capture beings and then use near-light speed travel to align civilization in time.
[+] [-] Balgair|8 years ago|reply
[+] [-] dghughes|8 years ago|reply
>They would also be brightly illuminated by the central singularity and by photons trapped in the same orbit.
That sounds creepily like a typical description of heaven. Timeless, ageless, godlike beings all in a region of intense uniform brightness.
[+] [-] samstave|8 years ago|reply
[+] [-] v_lisivka|8 years ago|reply
[+] [-] teraflop|8 years ago|reply
http://www.gregegan.net/PLANCK/Complete/Planck.html
[+] [-] LoSboccacc|8 years ago|reply
Maybe the background radiation is the part of the hawking radiation that falls inward. And we perceive it infinite but it’s the dilatated space between the hevent horizon and the naked singularity at the center. And the big bang was the supernova that left the black hole.
Trippinng!
[+] [-] neilsimp1|8 years ago|reply
I love animations where it zooms out farther and farther into space, until it gets to the point where galaxies start to resemble molecular structures.
And then of course The Simpson's did a couch gag where exactly this happens and they zoom out and out into space until it finally zooms out of Homer's own head.
[+] [-] hliyan|8 years ago|reply
[+] [-] v_lisivka|8 years ago|reply
[+] [-] dlwdlw|8 years ago|reply
[+] [-] garmaine|8 years ago|reply
[+] [-] hliyan|8 years ago|reply
[+] [-] zmyrgel|8 years ago|reply
[+] [-] imglorp|8 years ago|reply
[+] [-] aagha|8 years ago|reply
[+] [-] dave_sullivan|8 years ago|reply
[+] [-] ThomPete|8 years ago|reply
Could it be that these type III civilizations are simply consuming so much energy that that in itself becomes the black holes?
The KARDASHEV Scale explained. https://www.youtube.com/watch?v=9k-Kuc9esDI
[+] [-] jweissman|8 years ago|reply
Such civilizations might be like “simple germs”, their self-sustaining black hole vessels interacting and stirring things together; perhaps the cores of the most “interesting” galaxies are sentient, waiting for one femto-tech civ to arise from a trillion slime-ball planetoids — to make first Contact...
The more general possibility of “intersecting” reality at right angles has been taken up in a few additional works I can think of: in Count to Infinity and Excession.
[+] [-] machinshin_|8 years ago|reply
[ ... snip ... ]
> In theory, highly advanced aliens could live on such planets, being unobservable from outside while exploiting the high energies and large time dialtions available.
reminds me of Frederick Pohl's Heechee Saga.
[+] [-] bArray|8 years ago|reply
Also, isn't the assumption that there is a "big crunch" (also a good name for a cereal if it doesn't exist)? We're not sure whether there is a big crunch or heat death? This still seems plausible whether there is a big crunch or heat death - either way a black hole may be the only way for a civilization to stay alive at "the end".
[+] [-] simonh|8 years ago|reply
[+] [-] tziki|8 years ago|reply
[+] [-] kiliantics|8 years ago|reply
[+] [-] gilbetron|8 years ago|reply
[+] [-] beached_whale|8 years ago|reply
[+] [-] tritium|8 years ago|reply
The black hole wouldn’t be older than the universe. The black hole is just older than the last, most recent big bang, and the big bang doesn’t explain anything anymore.
It’s disproven as an event of creation. The big bang just becomes different parlance for turtles all the way down.
[+] [-] unknown|8 years ago|reply
[deleted]
[+] [-] duckwho|8 years ago|reply
[+] [-] pwaai|8 years ago|reply
what if Buddha was right in that there are thousand fold universe systems each with their own unique civilizations?
If there are blackholes older than the universe itself, what if that suggested the universe was cyclical and that we may be in some gazillion-th iteration?
what if big bang was just a universe eventually being consumed by a monstrous blackhole that collapses itself?
What about the strange UFO occurences that pentagon acknowledged, are we getting visits from aliens within our universe or from another universe? Have they figured out how to travel between multi-verse, that is if you believe in it?
No proof, no way to find these answers but it really makes me wonder, especially when particles behave strangely like being coupled regardless of distance...but how could Buddha have known that blackholes existed?
https://www.reddit.com/r/Buddhism/comments/6o8zmg/the_buddha...
Anyways, just some things to ponder and gawk about...
[+] [-] krapp|8 years ago|reply
The Pentagon has never acknowledged the existence of extraterrestrial craft, or of UFOs as being anything but hoaxes and misidentified, mundane phenomena.
>but how could Buddha have known that blackholes existed?
He didn't, any more than the Norse knew that wormholes existed when describing the Bifrost bridge or the World Tree. Reading modern scientific meaning into ancient religious ideas is a common way to attempt to validate religion, but doing so does a disservice both to the religion and to science.
The Buddha may have had many insights, but none of them involved the relationship between spacetime and gravity.
[+] [-] JumpCrisscross|8 years ago|reply
Yes there are. Answering such questions is why physicists are searching so hard for a unified micro/macro theory. Black holes are both quantum mechanical (at their singularities) and relativistic.
> how could Buddha have known that blackholes existed?
He didn’t.