For all we know the universe decides to save memory and just not render anything there at all.
My sense is that we've got it flipped, and have so strongly embraced the 'realism' of quanta that we intuitively reject some of the more continuous features of GR, whereas if I was putting forward the candidate for the secondary 'rendering' side effect, it would be the conversation of continuous modeled things to discrete units for tracking state from interactions with free agents so optimized that erasing persistent information about the interactions converts back from discrete to continuous.
We've now seen that paradigm with procedural generated environments with deformable geometry where continuous seed functions convert to voxels that are tracked.
Maybe the foundation of existence is continuous and infinitely scaled, and it's only our own emulation of that foundation where there's conversion to discrete units and fundamental limits preventing any 'real' infinites?
I've never seen anything asserting this, and this is not what standard theories say. The idea is that with the right "key" you can recover the information that was encoded in the stuff that fell into the black hole. As far as I know there is no suggestion this gives you any information about what is going on inside it.
https://www.quantamagazine.org/new-calculations-show-how-to-...
I wouldn't put money on it being the case, but it's definitely "outside the event horizon" thinking and worth a read.
The preprint linked to lays it out more technically if that's your jam:
https://arxiv.org/pdf/2207.06536.pdf
See section 6 on exterior vs interior measurements, and you can see the discussion in the FAQ about how measurements on the radiation after the Page time creates particles in the interior (which cites section 6 for more details). Then 8.2-3 goes more into what information about the interior can be known from observables in the fundamental description before and after the Page time. The "Previous attempts at an encoded interior" section in the discussion could help further clarify things.
It's not saying that it's trivial to see inside a black hole from the Hawking radiation, but it would be incorrect to characterize their model as saying that nothing about the interior can be known in measuring the Hawking radiation.
This is quite different from being able to probe the space-time structure inside (i.e. ask questions like is there a real singularity in there).
If you think about what you'd need there, you need the opposite of what they have in the FAQ, you would need operations in the interior to be able to create a particle on the exterior in order to build a "telescope" to look inside and I'm pretty sure this is ruled out even in this proposal.
It just admits that the feasibility of this is ridiculous with my favorite line of the paper:
> Physically this seems absurd, as it allows a measurement inside a black hole to produce a record which stays outside, but we are not claiming that any effective-description observer could actually implement this unitary.
But I agree that there's a big difference between the plausibility of measuring the 'stuff' vs it's spacetime configuration - that was a great point.
In any case the picture of time and space switching places inside a black hole is at best a rather deceptive simplification. The most important thing about the event horizon is that locally (i.e. to one falling in to it) nothing at all interesting happens at the event horizon.
Edit: The "swapping" you are referring to is an artifact of coordinate systems, not of space-time. Thinking something wild happens to space-time as you pass through the event horizon is the same as thinking that something wild happens to the Earth's geometry as you reach the north pole. Sure at the north pole there is no longer any meaningful direction other than "south" but thats an artefact of the coordinate system you're using, the pole is a normal point just like any other.
If you picture us in an X-Y plane (which somehow represents all 3 spatial coords), and "up" is the time dimension, then a black hole would be the X-Y plane deformed into a 90-deg "pipe" facing straight down. Once you are in the pipe, your "X-Y" is our "up-down", this is probably the "artifact" you are referring to.
This is not correct, there is no 90 degree bend. Space-time is locally Minkowskian ("flat") at the event horizon. It looks like a sharp 90 degrees turn in some coordinate system, just as when you walk in a "straight line" (a great circle if you prefer) over the north pole you go discontinuously from "walking north" to "walking south" even though your real motion is continuous.
And even you could always just pick a coordinate system with the origin right where the particle is, then its coordinates would trivially be zero. If you have several or moving particles and you want to keep the coordinate system fixed, then this will of course no longer work.
So even if spacetime is continuous and particles do move within it in continuous ways, the combination of Heisenberg's uncertainty principle plus the Plank length means we can never observe such continuity anyways.
I think the statement that you are implying here is not known to be correct. We have no idea if it is (theoretically) possible to measure the position of a particle to a precision of less than a Plank length. In some formulations of quantum gravity there are fundamental limits like this, but quantum gravity is difficult at best and sketchy at worst and none of those versions of quantum gravity is without their flaws.
If there's not enough energy in the universe to make the measurement, then there's no making the measurement no matter the theory of what would happen if there were more energy.
We could discuss the theory of what happens to a virtual photon going down a split path between Everett or another interpretation, but if we can't ever actually measure the virtual photon, then it's just theorizing around an unanswerable question. Which is part of what leads to "shut up and calculate."
We've known about the limitation in space for a while with the Plank length, and a similar limitation in time was discovered a year or two ago.
So while we have successful models for the universe that rely on the notion of continuous spacetime, our measurable version of it effectively has a minimum pixel size beyond which we fundamentally cannot get any more detail.
Fit the first time the other year I saw a psychics paper that actually presumed discrete spacetime based on simulation theory, which was pretty funny. I don't think the paper is that interesting beyond that aspect, but maybe you'll enjoy it given the presumption of discreteness: https://www.nature.com/articles/s41598-020-76301-0
I don’t want to dismiss it off hand because there’s all sorts of funky things out there, but “information encoded radiation” is something that I’d be pretty immediately and heavily skeptical of.
But I think you're overcomplicating it. Think of it as a snapshot of an object as it crosses the event horizon. That snapshot is etched into the "surface" of the horizon and emits a pattern of radiation that corresponds to it.
It's pretty much the same as dropping a rock onto a planet and observing the crater from orbit. You left a mark on the surface and it emits a corresponding pattern of radiation.
The real crux of the matter is that we're starting to understand that information is a lot like energy. It's generally conserved in the same way, but black holes appear to destroy matter, energy, and information in a way that doesn't really add up.
So Hawking came up with the idea of Hawking radiation. It's a hypothetical way for a black hole to very slowly give back all of the matter and energy it's consumed in the form of particle radiation. If information is a conserved quantity like energy, Hawking radiation must also return all information consumed by the black hole.
Information theory is pretty interesting if you're the type of person who likes to think about black holes and cosmology in their free time.
AFAIK we haven't proven that Hawking radiation actually exists. It seems to work mathematically, but we'd have to go out and observe a black hole up close. It's also extraordinarily slow. As in, it would take the entire lifespan of the universe for a big black hole to evaporate into nothing. Ten to the power of hundreds of years. Just a hair shy of infinity.
Nothing.
To me, the resolution of the paradox — that the radiated field might contain some encoded information in it — is less weird than the alternative, which is that the information somehow disappears. Information being encoded in a field seems natural to me. There’s a tight interplay between energy, temperature, and information. It’s even right there in the first law of thermodynamics: dE = TdS + dW. (The S is the missing information about the system.)
At least unless you can somehow reduce the data complexity dramatically without tainting the simulation, but that seems difficult to do when you're trying to work backwards to an unknown state. At least the pre-burnt piece of paper is known to exist alongside various rules of physics that we know - unlike in the black hole, where those rules all come with a "warrantry maybe void" asterisk.
But yes, if you have "collapsed the wave function", you don't have the information to "backtrack" anymore. But I don't think the information paradox is about this (although unsure why). AFAIU one problem is that black holes throw out even the statistical information available in the wavefunction.
The other thing I've wondered is how could you have a detector for those particles without interfering with your measurement (heisenberg's)? Your measurement apparatus will give off heat or very slightly change the shape of spacetime, thus interfering where your particles are detected :(.
What really bothers the quantum physicists is not a macro-scale unrecoverability, but the event of the loss itself. The equations of quantum physics do not have anywhere to "lose" information. If a black hole loses information, then that means there is some box you can draw in spacetime where the information goes in and doesn't come back out, and that necessarily implies that something in that box broke the fundamental equations of quantum mechanics.
I think you could analogize this issue into classical physics fairly well as finding a violation of the conservation of energy in a putatively classical system. (I have to qualify this because at it stands at the moment, conservation of energy is not absolute; at cosmological scales it seems to be violated by the expansion of the universe. So ignore that for the moment.) If someone produced a true perpetual motion machine, let alone one that actually provided over-unity energy, that would be a problem for classical physics because there is nowhere in the mathematics that energy can be produced in excess. It is written into the most fundamental formulations of the theories and backed by Noether's Theorem. Such a machine would mean that somewhere the laws of physics are being violated, and that would mean we have a hole in them. The quantum theorists are "worried" about quantum information loss in the same way a classical physicist is "worried" about over-unity machines. A real, physical quantum physicist or classical physicist might in fact be over the moon to discover such a thing; it would be a career maker and who knows what else might be implied by such a discovery. But the anthropomorphized theory that was just "violated" would be very "upset".
The other major relevant different being that the classical physics has those classic physics "in hand", in the sense that many real experiments on classic physics can be and are realized in the real world, and at this point, physicists as a whole do not take the idea that an over-unity machine is going to be produced very seriously. However, it is quite difficult to have black hole in hand to experiment on; such mathematical analogs as we have are intrinsically limited and probably quite likely to fail to exhibit the phenomena we're interested in. So there's a lot more "room" for problems to come from. Plus, classical physics already has very firmly built into it the understanding that it is only an approximation. Quantum physics is still struggling with that question; sure, we basically know it is incomplete, but we don't know exactly how to resolve that, so unlike classical physics where we know that technically, yes, it's predictions can be violated in certain ways at certain scales and we accept that, we're a lot more nervous about QM. Maybe the real theory of the universe would allow information destruction. In English, that sounds pretty harmless ultimately, like, I mean, OK, maybe that's a bit of an issue but who cares? But pushed through the aforementioned Noether's theorem it gets much more interesting considered from the mathematical point of view, and much more challenging.
The smallest perturbations in a chaotic system yield completely different results. The slit experinment for instance suggests that measurement changes the system.
Yes, prediction doesn't and can't contain information (in the technical sense) from the future, since by definition it's based only on what we know in the present.
> Do we have some ideas why rules of physics will be different in the future?
No. It's perfectly reasonable to assume that the rules of physics will be the same in the future. Just as it's perfectly reasonable to assume that they're the same inside a black hole. But in both cases we can't know.
In the technical sense the future _is_ driven purely by the information available in the present. It’s a function of t-1.
The only reason future should be different from prediction is if the set of information available to the predictor about the present is different from the actual set of information about the present.
The best way this word fits is that we can reason towards the conclusion that whether laws will change or not is an assumption.
Sure it can, you just have to be patient.
If you reject the theory because it makes unfalsifiable claims, you no longer get to claim they are unfalsifiable.
The leap that I'm raising an eyebrow at is the assumption that GR is applicable "inside" of a black hole. It's a very nice theory: it knows its boundaries. It's a little strange that we're trying to apply it on both sides of those boundaries, given that they are also our boundaries.
I wouldn't go so far as saying that applying GR inside a black hole is like applying GR in a critique of Star Wars, but I do think that that's the sort of distinction we're talking about here. Assuming the consistency of the laws of physics across separate universes might be kid of cool, but it's never going to be as justified as assuming their consistency within the same universe. And that's what the inside of a black hole is, supposing it exists: a separate universe, a place that will never be in our light cone.
(Or, GR is wrong, and we actually can get information from there, which would be interesting too, but I'm assuming for the present that GR will continue to make good predictions.)
EDIT: Oh, and there are people trying to do that, I think, but it's not that easy.
And all true claims cannot be proven by science. Proof is the domain of logic and math, in science you can only falsify things.
I quoted this earlier I'll just quote it again for people who don't believe my second statement about science:
"No amount of experimentation can ever prove me right; a single experiment can prove me wrong." - Albert Einstein
So your statement, while not intentionally so, is pointless.
I think the main difference people are missing here is that everything beyond the event horizon hasn't ever been observed. And it's theorized to be unobservable.
That’s not what ‘falsifiable’ means. ‘Pi is irrational’ is falsifiable, in that if you can show me integer p and q such that p/q = pi, you would have demonstrated that statement to be false.
The fact we can show that no such p and q exist is what renders the truth of that statement proven. ‘Falsifiability’ of a statement is the property that makes the statement amenable to being evaluated for truth.
This is misunderstanding what falsifiability entails. A claim is falsifiable if one can, in principle, come up with experiments to disprove it. Just because a true claim will never be disproven by those experiments does not make it unfalsifiable. It could have been disproven, had it been false, and that is enough.
If your way of defining it is true then it's just a bad formal definition of falsifiability because you can make a sentence that sounds nonsensical like the one I made above. It means falsify and falsifiability are two different words with different definitions. When you look at the words they appear to be the same word with just different suffixes.
Let's examine the implications of your definition more carefully. If I falsify something. I either failed or succeeded at falsifying it. If there exists a thing that where all possible attempts at falsification will fail then it is still "falsifiable" because the attempt to falsify was possible??
If you are impossible to kill then you are still killable? If numbers cannot be divided by zero but it is still "divisible" by zero because I can make a fool hardy attempt at it?
From this I will say that my colloquial use of the term is actually better than your claim about the formal definition of falsifiability.
Better to use the word "observability". One cannot gather observable evidence to conduct an experiment. That's the key differentiator here.
So falsify refers to the result but falsifiability does not?
Reread my post, I don't think you read it fully. If falsifiability is defined as your claim then such a statement can be true:
"The Pythagorean theorem cannot be falsified but it is falsifiable"
Which sounds obviously nonsensical.
This is inconsistent with how we use the -able suffix in other words:
"The code cannot be extended but it is extendable"
I'm not referring to any official definition here, just pointing out the language problem that arises if we assume what you say is true. But here is the official definition anyway:
https://www.dictionary.com/browse/falsifiability
Which basically is pretty solid evidence for you being wrong. But at the same time I think you all are pulling some formalized definition from philosophy or something which probably has a different meaning defined for it. My argument is that the formalized definition is worse than the colloquial one in the English dictionary because the English definition is more logically consistent with the rest of the English language.
It's debatable which definition is more appropriate for this context. But assuming not everyone is a philosophy major I would say the definition in the English dictionary is more relevant.
falsifiability - the ability to be proven false. That's what it says in the dictionary.com link as well. It is not necessary for something to be false for the ability to prove it false to exist. That's "The chance of it happening was 100% because it actually happened" levels of word-twisting. I think it's a variety of begging the question, where you assume the outcome in your premises. If the coin flip lands on tails, the chance of it landing on heads was not 0%.
EDIT: Try this - substitute 'testable' for 'falsifiable' and see if that helps ease the dissonance.
No if something is true, it does not have the ability to be proven false. That's the obvious meaning at face value. Your definition is the one that's twisting things up here.
A person with no legs does not have the ability to walk. The implication of your logic is that a person with no legs can walk. Just like how a true statement can be proven false.
The statement also doesn't deal with probabilities. So your probabilistic analogy isn't relevant. When you say something can be falsified that is entirely different from saying that there's a probability something can be falsified.
>EDIT: Try this - substitute 'testable' for 'falsifiable' and see if that helps ease the dissonance.
Why?
Of course it helps. Because you chose a word with a different definition. I already know what you mean. You can leave the word as is, I still know what you mean and it's still logically consistent with your point.
I'm just pointing out the inconsistency with the linguistic aspect of your word choice that leaves it amenable for other people to interpret it differently. The original point is moot. We're talking about a linguistic problem here. Replacing the word is side stepping the original linguistic issue.
The pythagorean theorem is not an example of a falsifiable claim. It is a provable claim, the opposite of falsifiable. Though again, this has nothing to do with it being true or false. Bigfoot married Elvis is likewise a provable claim, a claim where evidence could be presented that would prove it true if it were true. The inverse, Bigfoot did not marry Elvis, is falsifiable, because evidence could be presented that would prove it false if it were false.
There's nothing nonsensical about it. Lots of things are extendable even when they're not extended, foldable when not folded, recyclable when not recycled, and falsifiable when not falsified. The colloquial definition is the same as the formal, you're the only one using it your way.
The lottery yesterday is not winnable by me because it was already won by someone else and because I already lost. That is a fact. That's a valid statement taken at face value. It's not nonsensical at all. There's no subtle word twisting here.
Do you actually go around saying the lottery was winnable after it was already won by someone else? Your example is the one that at face value seems more twisted.
You are also dealing with probabilities. Falsification by the word itself "false" deals with boolean logic. True or false. There is no probability here which you introduced with your "lottery" analogy. It's not really applicable because something can't be false if it has a probability of being true or false.
> Falsifiable doesn't mean proven false, it means able to be proven false, even if it isn't.
Again you're not addressing my point. I know what your definition IS. And I stated before, and I will state again that if we assume your definition is TRUE there is an inconsistency between the word "FALSIFIED" and "FALSIFIABILITY". This is a linguistic problem with your word choice.
But read your own statement carefully. Even your definition doesn't make sense. How can something have the ability to be proven false if it isn't false? That doesn't even make sense. What you mean is that a statement can be tested in attempt to be proved false. I'd be pedantic to hold you to that but I'm not. But I will hold on to the fact that the error you made in your language is a linguistic issue and not one with your logic. The linguistic issue is what I'm referring to here. That's the inconsistency I originally pointed out.
If something is falsified it is false. But by your definition it can be both falsifiable and not falsified and not false. I didn't say that YOUR definition made the statement nonsensical. I said it sounds nonsensical because the face-value definition makes it nonsensical. Which is equivalent to saying any average person will find it to not make sense because they defined the word traditionally while you defined the word differently.
>There's nothing nonsensical about it. Lots of things are extendable even when they're not extended, foldable when not folded, recyclable when not recycled, and falsifiable when not falsified. The colloquial definition is the same as the formal, you're the only one using it your way.
You're not getting it. It's not my way. It's you. You're extremely far away from understanding logic. We can tell from this statement here:
>Though again, this has nothing to do with it being true or false. Bigfoot married Elvis is likewise a provable claim, a claim where evidence could be presented that would prove it true if it were true.
In science and therefore reality as we know it there is no such thing as a provable claim. Nothing in reality can be proven. Falsification is the only methodology available to us. Read the first section here: https://www.wikiwand.com/en/Falsifiability I'll quote it:
"Popper contrasted falsifiability to the intuitively similar concept of verifiability that was then current in logical positivism. He argues that the only way to verify a claim such as "All swans are white" would be if one could theoretically observe all swans, which is not possible."
Which means you can't prove all swans are white. It's impossible. But you can falsify it by finding one black swan.
You'll also note on the same wikiwand page it says this as the second sentence: "A theory or hypothesis is falsifiable (or refutable) if it can be logically contradicted by an empirical test."
By definition a true statement can't be contradicted by an empirical test. So even the formal definition is inconsistent with your claim.
I entirely get how the word is used in the scientific community and what you are referring to but the formal definition here is just a poor choice made by Karl Popper or whoever it was who coined it and it doesn't mesh with the rest of English. It allows for wikipedia to mistakenly have a definition that by logic cannot be applied to true statements. If we just replace some words and apply that definition you get this:
"A true statement that is falsifiable by definition can be logically contradicted in a empirical test"
It can't man, let's be real here, don't twist it.
>Lots of things are extendable even when they're not extended, foldable when not folded, recyclable when not recycled, and falsifiable when not falsified.
Ok this. This is word twisting. It's almost deliberate. Nobody made any statements like this, you twisted the analogies slightly to fit your agenda. Let's make things more accurate here:
If something is can't be folded it is foldable. If something can't be recycled it is recyclable. If something can't be falsified it is falsifiable. These sound contradictory at face value. Ask anyone.
The ORIGINAL claim was this: "All true claims are unfalsifiable by definition."
A true claim is equivalent to a claim that can't be falsified. So I essentially said, "All claims that can't be falsified are unfalsifiable by definition" and you're saying that claim is wrong. Let's be real.
We're getting pedantic here, but ultimately the logic spells out that I'm right.
But in the end we all know that new physics need to be developed because the assumption is that there is only one reality and thus we should strive to reach a unifying theoretical model. Or are you suggesting there it is not possible to achieve a single theoretical model of reality?
Careful readers and writers will observe that we do not. What physicists actually say is "IF this theory is true, THEN we can say this and that about what lies within a black hole."
Since at the moment we do not have any satisfactory theory that accurately describes black holes, every such if-then statement is known to be flawed, and a careful thinker will recognize these as being exploratory examinations of what theories imply, and a search for testable predictions, rather than dogmatic declarations of the true nature of the universe. Sometimes, for instance, you can explore a theory and determine that it makes contradictory predictions, which means you can toss that one out. Exploring mathematical hypotheses is a perfectly sensible use of research time.
However, careless readers, writers, and thinkers abound.
I think it is the general sense of physicists in general that there probably isn't a singularity in a black hole. There is almost certainly something there that is sensible under some theory. Extreme, sure, but sensible. It is relativity and derived theories that specifically yield singularities, but we also know relativity is not a complete description of the universe.
Even this article, if read carefully, is not saying "black holes do not in the real universe have singularities". It is saying something much more like "Previously physicists have accepted that IF the mathematics of Einsteinian relativity is true, THEN black holes have singularities. However, if you analyze the mathematics more carefuly, this IF-THEN does not in fact follow from the mathematics." It actually isn't a claim about the real universe, which is already known to not be purely described by Einsteinian relativity, but a claim about Einsteinian relativity qua Einsteinian relativity as a mathematical theory.
Of course, the whole reason anyone talks about singularities in black holes at all is precisely Einsteinian relativity in the first place. Quantum mechanics isn't the reason, nor any other alternate Theory of Everything that I know of. So if they are removed there, we are left with no reason to suspect singularities exist in any sense.
That still doesn't mean that we positively know what goes on under the event horizon. It would merely eliminate one "IF relativity THEN singularity" from our current discussion. Still progress in its own important way, but perhaps not as groundbreaking as a popular press treatment might claim.
Second, was general relativity falsified or are you referring to generally accepted speculation? If it was falsified, do you have a source?
I'm not making some whacky fringe claim here; this is actually completely mainstream physics. It just isn't as well understood by the laymen as it ought to be. The previous paragraph is a summary and you can get into lots of nuances and details and such, but in the end the underlying fact remains that at the moment nobody knows how to put relativity and QM together. We have several theories, none proved and all with problems, and there was even a new entrant this very week.
Relativity and QM are two of the best theories we've ever had in the world, in terms of the number of digits of precision they are accurate to... and in some sense that is one of the biggest problems with them. We know they don't go together as written, but to know how to weave them into something that covers both domains correctly, we either need real-world phenomena that they do not correctly predict, or the ability to do experiments in the regime where they disagree (which is why black holes are so interesting to physicists), and we're basically empty handed for both those things.
Could the inside of a black hole be an "observable universe"? I ask because our observable universe is a little smaller than its Schwarzschild radius. Ie could our edges be an event horizon too?
The idea that no information can escape from the event horizon is model-dependent; it's a mathematical result from the assumptions of classic general relativity. If you operate with the assumption that the claim is true, it's fair to consider the other mathematical results of classic general relativity. That's why (some) people say there is a singularity.
Of course, the point is that if GR isn't exactly but only approximately true to a deeper theory, is the claim about singularities also true in the deeper theory, or does the deeper theory resolve the singularities somehow? That deeper theory may also say that information escapes from the event horizon.
For example, Hawking showed that semiclassical quantum corrections to GR means that black holes emit thermal (information-free) radiation. If we had a fully quantum theory of gravity people expect the evolution to be completely unitary and the information could ultimately be acquired (perhaps at enormous computational expense).
Also, I'm not sure you need stuff to always approach without ever getting there: it's not clear what happens to quantum fields at a singularity, but if you no longer have time displacement symmetry you don't get energy conservation so stuff might just cease to exist.
If you try to naively apply the same procedure you would use to define volumes outside the event horizon, it's proportional to the lifetime of the black hole (infinite in the classical case) for the reason you note.
Of course the better way to interpret this is probably just that the interior volume of a black hole is ill-defined.
Every geodesic that crosses the horizon terminates at the singularity in a finite amount of time. If you fall past the horizon the singularity is in your definite future and in a finite amount of proper observer time your geodesic will end, at which point ... who knows what happens.
We can imagine a civilization made up for very sturdy physicists, so tidal forces inside the black hole don't rip them apart immediately. This civilization can enter the event horizon of the black hole, and observe what happens inside, make measurements, new theories, write papers, upload them to pre-prints, go to conferences, etc.
It is true that they cannot communicate with the outside world, but that may not bother them if there's enough of them that they can share their new discoveries with each other and have a society and satisfy their intellectual curiosity.
According to classical general relativity there are no stable orbits inside the black hole, so eventually this society will get arbitrary close to the singularity (or, to extremely large curvatures), so eventually they all would die, irrespective of how sturdy they are.
But this is also true outside the black hole, per our current best theories, we will all either get crushed in a big crunch (reverse of the big bang), or heat death as the Universe expands indefinitely. (Or, sooner, when the sun explodes, or sooner if an asteroid hits us, or global warming, or we nuke each other..)
The person entering the black hole does not perceive time freezing. How could he? Relative to himself he will enter the black hole but for him time outside of the black hole will accelerate at infinite speed well past the heat death of the universe forever in an instant. Then once the universe ends if there is an end, he will cross the threshold and move through the event horizon.
For the outside observer, it seems like nothing enters the event horizon. It seems like everything just gets infinitely close and redshifts and expands, and forms a giant low-energy redshifted enveloping pancake around the black hole.
But, from the perspective of the object passing through the event horizon, none of this happens, she passes through just fine.
Yes, relativity theory is weird as hell.
It's true that infalling observers will experience outside time speeding up, and conversely outside observers will see infalling objects slow down. In fact, as they approach the Event Horizon, they would appear to experience diverging time dilation. So in effect, they become "frozen in time". But remember that you can always maintain two-way communication with light. The very fact that both the outside observer can always see the infalling person and the infalling person can always see the outside world imply there can be two-way communication all the way up to crossing the event horizon (which would take infinitely long for the outside observer). This ought to be enough to conclude the infalling person can in fact never reach the event horizon.
And the infinite passage of all external time is observed in a finite time by the infalling observer. All of the communication from the external observer is going to become a high frequency chirp at the event horizon, and the last message the infalling observer could send will take nearly an infinite amount of time to reach the external observer. And in the next instant of subjective time by the infalling observer they will be past the event horizon and unable to communicate any more.
If you have a classical black hole and you don't bother yourself with how it forms, though, there's no paradox, the paradoxical effects arise because the areas of space-time become completely unreachable and you're using coordinate systems which are not local.
The person falling into the black hole will have time in the outside universe accelerate relative to him. It will get faster and faster and when he hits the event horizon we don't know what happens as that's the singularity where the math no longer works. We can speculate that time actually freezes but that leads to paradoxes.
Yes, but due to the extreme time dilation, will they observe/experience the heat death of the universe prior to entering the black hole?
If so, does it make sense to say they actually enter it in any meaning full sense from the perspective of our existence?
As in 'yes', they will enter the black hole, but they will enter it an infinite number of years from now when our universe "functionally" no longer exists.
Isn't this just another form of a particle with constant acceleration, accelerating to the speed of light? Yes, from their perspective, they reach it, but from our perspective, it will take an infinite amount of time and so we say they never can reach it from either our perspective or theirs? I don't see how this can be any different. Gravity is a constant accelerator.
(And note I'm calling out the constant acceleration case above for approaching 'C', not the increasing acceleration requiring 'exponentially increasing energy each second' case).
From the perspective of the observer nothing enters the black hole. This is true.
From the perspective of the person entering the black hole he does enter it. It's because of time dilation.
Both of these statements are true according to theory as far as I know.
Sure, there's no evidence for this (yet?). But it'd be a nice solution to the paradox.
Itm similar to science fiction where time loops resolve through circumstance. If you go back in time to stop your birth you will inevitably instigate your birth instead of creating a paradox.
I'm this case if you try to freeze time by going into the black hole the black hole will inevitably be destroyed before you can get close enough to it to encounter the singularity.
Side note, I watched this almost B movie called "time trap" and I feel like falling into a black hole would be just like the end of that movie. It really made me want to jump in a black hole.
The black hole evaporates at a finite speed relative to the outside observer. So someone falling in will by logic see this evaporation speed accelerate.
Before he touches the event horizon the black hole should have completely evaporated already so time never actually "freezes".
That's an interesting solution and resolves the paradox. When the black hole evaporates the reference frames become consistent again.
Don't get me wrong, I'm interested in hearing about some maximally elegant mathematical model which is consistent with the observations and the laws of physics on our side of the horizon. I just don't think I would then proceed to believe that what they described was a reality on the other side of that horizon.
1. https://en.wikipedia.org/wiki/Black_hole_information_paradox
Does the physicist believe that? If we get past popular culture which mangles modern science, the physicists are throwing around lots of random "what if" ideas and seeing where they go. If one is good, their idea is popular enough other physicists spend time thinking about if. If one gets lucky, then someone comes up with a way to test the theory (using the layman version of theory). If one gets REALLY lucky, the test doesn't lead to it being rejected.
Sometimes there an be a long gap between when a physicist first thinks of a theory and someone finds a way to test it. Some ideas are still untestable, but may be interesting enough that physicists will still try to dive deeper and see where the idea goes.
But do they believe it is the truth? While some might, I think most keep a sort "what if, maybe" vibe, even on the theories they spend time looking into. They are invested, but that doesn't mean the believe it is the truth, only that it is the model worth spending their time investigating.
One key idea to consider, science does not give truth, it gives the model that best fits all known data without any claim to if that model is true or false.
We have theories and experiments.
An experiment giving a result not in accord with the theory is an immediate disproof.
An experiment giving a result in accord with the theory is a confirmation possibly waiting for another experiment resulting in a disproof.
Proof exist only in mathematics.
Also I'm sure you already know that we can't prove anything to be true either in science and therefore reality, so basically the universe outside of the black hole is full of falsified statements and unprovable statements... and we just assert that some of those unprovable statements are true. For example: general relativity.
"No amount of experimentation can ever prove me right; a single experiment can prove me wrong." -albert Einstein
If LIGO is able to retrieve information from the insides of black holes that should be earth-shattering news, no?