## Math Shows Some Black Holes Erase Your Past and Give You Unlimited Futures (vice.com) 190

dmoberhaus writes:

*An international team of mathematicians has found that there are theoretical black holes that would allow an observer to survive passage through the event horizon. This would result in the breakdown of determinism, a fundamental feature of the universe that allows physics to have predictive power, and result in the destruction of the observer's past and present them with an infinite number of futures.*The findings were detailed in a report published last week in*Physical Review Letters*.
## Re: (Score:2, Troll)

They field they are in is "left".

## Re: I KNEW IT! (Score:4, Interesting)

I'm not in the field either, but I hope someone can explain this a little better since the actual paper is behind a paywall and the oversimplified and popularized Motherboard article doesn't make any sense.

Motherboard says that the laws of the universe, outside of black holes, are supposedly deterministic. That's news to me, I thought quantum mechanics dealt with probabilities and there was no way to predict what part a particle will take. The universe plays dice all the time, it only appears to be deterministic on a large scale when the probabilities of the individual particles average out to a largely predictable macroscopic result.

Then, what does it mean when they say your past is destroyed? Let me get this straight, you fall into one of these special black holes, you survive (which, I assume, includes your memories), yet your past is "destroyed"? I imagine they mean that the laws transfer to a different coordinate system where your past is no longer at negative time coordinates but simply nowhere at all. Which isn't really that unusual. Just use a different coordinate system (one tied to your body) and the past will be there again, still inaccessible at the usual negative coordinates (but formulas for describing your current environment will be very complicated). Pretty sure that's what they meant, right?

OK, what about the unlimited futures? Again, I though quantum mechanics already gave us those. I guess it means that the future will be a lot more undeterministic than usual?

Finally, the big discovery seems to be that you won't be destroyed by all the energy of the universe falling through the event horizon at the same time as you, thanks to the expansion of the universe. But what about spaghettification? Won't you still be killed by the enormous differential gravitation even if you survive the radiation at the horizon? How does the charge of the black hole prevent that from happening?

Thanks in advance to anyone who can clear this up a bit more.

## Re: (Score:2)

Motherboard is full of shit. A brief study of complex systems and emergence will convince most people of what many already know. Namely, that the universe we can observe is anything but deterministic. This is perspicuous and observable at the macro level, without even having to appeal to the mystical incantations of the quantum level.

Looks more like a hype article based on false assumptions and completely eviscerated of any possible relevance by a combination of click-hunting and grant-hunting word sieve

## Re: I KNEW IT! (Score:5, Interesting)

> Finally, the big discovery seems to be that you won't be destroyed by all the energy of the universe

> falling through the event horizon at the same time as you, thanks to the expansion of the universe.

The catch here is that, "all the energy in the universe," may not be hitting you as you fall through the event horizon, but a lot will, more than likely enough to give you a Bad Day. You're only down from "infinity" to "the horizon observable over the black hole's future," still a pretty big number.

> But what about spaghettification?

Others have answered this, that the gravity gradients are soft enough around a big enough black hole.

There is another fun fact here... For spinning black holes, which I believe means most of them, or at least the big ones we could think of entering in the non-spaghetti state, there are actually two event horizons, and it might be possible to leave from the zone in between them. Gregory Benford, physicist and science fiction author, set several books in that region.

## Re: (Score:1)

The catch here is that, "all the energy in the universe," may not be hitting you as you fall through the event horizon, but a lot will, more than likely enough to give you a Bad Day. You're only down from "infinity" to "the horizon observable over the black hole's future," still a pretty big number.

Indeed, that's another thing I was wondering about but forgot to mention.

For spinning black holes, which I believe means most of them, or at least the big ones we could think of entering in the non-spaghetti state, there are actually two event horizons, and it might be possible to leave from the zone in between them.

Wow, you learn something new every day, thank you!

## Here is the non-paywalled paper (Score:3)

https://arxiv.org/abs/1711.105... [arxiv.org]

## Re: (Score:3)

OK, what about the unlimited futures? Again, I though quantum mechanics already gave us those. I guess it means that the future will be a lot more undeterministic than usual?

It means that there is still a possibility that I get to have a threesome with Alizee and Selena Gomez. Now if I could only find a black hole...

## Re: (Score:1)

It's getting them to join you into that black hole that's going to be the hard part...

## Re: (Score:1)

My guess is that what they meant to say is that passage through the event horizon would violate causality, not determinism.

## Re: (Score:2)

Spaghettification is not a feature of event horizons, it is a feature of gravity wells. The spatial location where tidal forces turn lethal can be far below the event horizon of a very massive black hole, and higher for a small one.

## Re: (Score:2)

I'm not in the field either

I'm in the field and just stepped in cow poop.

## Re: (Score:2)

Motherboard says that the laws of the universe, outside of black holes, are supposedly deterministic. That's news to me, I thought quantum mechanics dealt with probabilities and there was no way to predict what part a particle will take. The universe plays dice all the time, it only appears to be deterministic on a large scale when the probabilities of the individual particles average out to a largely predictable macroscopic result.

It looks like the article conflates

determinismanddeterministic.Determinismis roughly synonymous with causality, which is what I assume the paper is talking about.## Re: (Score:2)

Let me get this straight, you fall into one of these special black holes, you survive (which, I assume, includes your memories),

It seems clear to me that to the extent that "you" fall into such a black hole, you are a particle not a human. Since, apparantly, once you're inside determinism no longer applies there is no way your human body with all its complex interactions will still function properly and you as a person will cease to be pretty fast.

## But volcanos (Score:2)

are so much more accessible

## In the Tesseract... (Score:2)

## Re: (Score:2)

## Let a mathematician go first (Score:3, Funny)

## Re: (Score:3)

Given that the nearest candidate for a black hole is approximately 3,300 light-years away, isn't this all kind of speculative?

## Re: (Score:2)

It's all speculative until someone proves it in meat space, but seeing as the people involved are mathematicians they have little interesting in so doing.

Actually it says at the bottom of the article that this probably will never happen, in fact the particular style of black-hole that makes TFS claims true may not even exist. Further, there are a lot of questions I have about the term "observer" and "making your past not exist".

Because one way I interpret this is that you won't be destroyed, you will be

un## Re: Let a mathematician go first (Score:2)

No no no no - they have PROOF that no fewer than 42 angels can dance on the head of a pin. The exact number is still under debate - some people say it's up to 700 angels. They have big math equations and everything. This is SCIENCE were talking about here, buddy!

## Re: (Score:2)

well how would you know you sent someone in if their past got erased?

the theory seems like a math foobar to me really, intuitively it cannot be true. of course the "erasing the past" in this sense I guess means something different, like they cannot access past information about themselves or something like that(meaning they're atom pulp) and have infinite futures (their atom pulp could become anything).

how is that even a theory though?

## Re: (Score:2, Insightful)

Theory and practice are the same in theory, but not in practice.

## Re: (Score:2)

Theory and practice are the same in theory, but not in practice.

Theory and practice are different in practice, but not in theory

## Re:Let a mathematician go first (Score:4, Insightful)

> Math containing infinties doesn't really work.

I don't wish to sound snide: But I think you'll find, if you look more carefully, that It works very well: Infinite series are much of the foundation of calculus. Even countable numbers, involve "infinities" because they are unbounded.

## Re: (Score:2)

Maybe a better way to put it is "Math treating infinity as a real number does not work."

I am not sure if that is what this paper did, as I can't access it. (And likely wouldn't understand it even if I could.)

## Re: (Score:1)

> Math containing infinties doesn't really work.

I don't wish to sound snide: But I think you'll find, if you look more carefully, that It works very well: Infinite series are much of the foundation of calculus. Even countable numbers, involve "infinities" because they are unbounded.

Actually there are many types of infinities...

The "infinities" that are used in most calculus are talking about limit-sets where you can define convergence under some type a metric (meaning they are bounded). However, if you are "counting" (such as number of possible futures), there is likely a whole nuther type of infinity.

In the relatively simple case of things that most people are familiar with we have the size of the infinity of the counting numbers (often called aleph-0). This is the size of your typi

## Re: (Score:2)

> Math containing infinties doesn't really work.

I don't wish to sound snide: But I think you'll find, if you look more carefully, that It works very well: Infinite series are much of the foundation of calculus. Even countable numbers, involve "infinities" because they are unbounded.

Actually, if you look more closely, and critically, you'll find that things aren't nearly as simple as you describe. For example, what you call "countable numbers" are neither infinite in number, nor unbounded. One hits hard physical limits as one tries to express bigger and bigger numbers. Computers have finite storage. Even if we imagine a computer as large as the known universe, with one bit in every Planck volume, there is only a finite number of numbers describable. The "set of all natural numbers

## Re: (Score:2)

The list of countable numbers is quite infinite in number, at least in the mathematical sense. One can always add "one" to the largest known number and generate a new, larger element of the set. The availability of resources with which to write the elements of a set does not mean the set is not infinite.

The idea of computational handling of numbers, and the difficulties of handling larger and larger recorded values, is built into the earliest models of a Turing machine, which assumed an infinitely long reco

## Re: (Score:2)

This is, ff I may say so, nonsense. Describing numbers is easily done at a higher level of abstraction. Given the approximate number of possible partcles in the universe of 10^86, I can trivially describe a far larger numnber as 10^100.

Ah, but even at a higher level of abstraction, there are only a finite number of descriptions possible. I'm not claiming that the set of all describable numbers is contiguous. There are huge gaps. For example, the number 10^(10^(10^(10^(10^(10^10))))) is easily describable but the vast majority of numbers between zero and that number are not. No matter how abstract and wonderful your description language, it must have a finite alphabet and there is only room in the universe for a finite number of symbol

## Re: (Score:2)

> there are only a finite number of descriptions possible.

There are a finite number of ways to write them due to, as you mentioned, limits on the availability of matter with which to write them. It is, if I may say, a gross fallacy to say that this therefore limits the maximum value of the descriptions. There are any number of notations available with which to write infinities, and extremely efficient ways to describe values well beyond the size of the numbers of the possible particles in the knowable un

## Re: (Score:2)

perhaps you meant that physics doesn't work well with infinities.

Infinities in math is fine and are used all the time.

## Re: (Score:2)

Mmm...no.

## Re: (Score:3)

## Re: (Score:2)

## Re: (Score:2)

FCOJ [npr.org]

## Re: (Score:2)

## There's an Aqua Teen Episode for this (Score:3)

"Math isn't going to bring you back from the dead"

https://www.youtube.com/watch?... [youtube.com]

## Re: (Score:3)

## Re: (Score:3)

We already did.

And we were really cruel about it.

## Re: (Score:2)

It is a copy.

Not according to my copy.

## Headline is gobledigook (Score:5, Insightful)

## Article is gobledigook (Score:1)

Or maybe just the hypothesis being espoused is. It seems like an indeterministic universe where effect no longer follows cause would be completely antithetical to life. Our existence utterly relies on cause and effect, without it, the first problem would be creating matter at all, let alone organizing into elements, then minerals, amino acids, cells, cell groups, and so on.

So... you don't have infinite futures if you were to cross the event horizon. You still have none.

## Division by zero? (Score:3)

When mass hits the speed of light, it does not travel back in time... It just louses all mass properties and turns into light.

1/(x*x) will never be negative with a real input!!!

## Re: (Score:1)

## Re: (Score:1)

# divide out (a - b)

Can't do that boss, a=b so you're trying to divide by zero.

## Re: (Score:3)

## Re: (Score:2)

Recipe to get infinite amounts of cake:

Bake 1 cake.

Now divide it by the number of ppl available. 1 cake / N people

Now make no one want the cake. N = 0

1 cake / 0 people = +oo cake / people

Now you have a infinite amount of cake per people.

Go end world hunger with it...

The number of people who want the cake has no bearing on how much cake you have. If 0 people want your cake, you still have 1 cake. Just like having infinite people want your cake. Math says you'd have 0 pieces per person. The fact though is you have 8 pieces of cake, people 9-infinity are out of luck. ;-)

## Seriously? (Score:2)

Physicists should not be mathematicians, they should be primarily physicists. Not everything is real what math allows. If that were the case, the SU(5)

model (https://en.wikipedia.org/wiki/Georgi%E2%80%93Glashow_model) would have worked.

Mathematics can describe reality, but reality is not mathematics.

## Re: (Score:1)

Mathematics can describe reality, but reality is not mathematics.

A claim often made, but no-one have succeeded.

What we do know is that mathematics can describe models of reality that have been specifically made to work with mathematics.

There are also other models that have been made with religion but those are mostly just wrong. (But interesting to mention as an example of non-mathematical models.)

So far no models have been perfect and we do not really know if reality follow the same laws as mathematics yet.

## Re: (Score:2)

Applied vs Pure, etc.

Keep hodling.

## Re:Seriously? (Score:5, Informative)

In quantum physics the approach of following the mathematical theory to its logical conclusion, how weird that may sound, has been quite successful. In any case such speculations make sense to test a theory and see where it leads to. Maybe it'll even lead to possible experimental tests of the theory (although I don't think humanity will have access to a black hole (specifically one that is big enough) to play around with.

The Einstein-Podolsky-Rosen-Paradoxon is a good example of following a theory (here quantum mechanics) to it's logical conclusion. Effectively the "paradoxon" exposes the nonlocality of quantum mechanics i.e. it implies "spooky actions at a distance", a picture that clashes with our classical world view. Based on this an experiment was thought up, a test of the "bell inequality". Basically any classical theory that preserves locality should always fulfil the bell inequality. OTOH quantum mechanics predicts a violation of the bell inequality in experiments specifically designed for that purpose. Such experiments then showed a violation of the inequality. This means, that a classical theory (which would include locality) can not explain those experimental results (which are predicted by quantum mechanics).

So the speculations of Einstein, Podolsky and Rosen about the strange consequences of quantum mechanic theory led to a fundamental insight about the nature of reality, namely that there are aspects of it that can not be explained by a "classical" theory that includes locality.

So if one wants to test a mathematical description of reality one has to follow the mathematics to its logical conclusions and if possible test if these apply to the real world. Even if such a test is not possible it is often helpful to see what the implications of a mathematical model are. Maybe it leads to a better understanding, uncovers contradictions or shows that a theory is incomplete, but in some cases it can also lead to a deeper understanding of reality.

## Only problem (Score:5, Insightful)

Math does not apply to reality. It always only applies to an abstraction of reality and that loses accuracy, sometimes catastrophically as almost certainly happened in this case.

## Re: (Score:2)

well, it most certainly can't erase it's own past effects on the universe by entering the black hole.

## Re:Only problem (Score:4, Interesting)

well, it most certainly can't erase it's own past effects on the universe by entering the black hole.

How can you be so sure? if it did, you wouldn't know.

## Re: (Score:2)

And how do you know that? And why would that not also be subject to change? You can be sure that any smart person would not tell you about deviations between their memories and history. Dumb persons often do not even know history and for the few ones that do and notice a difference, there is the loony-bin.

## Re: (Score:2)

Well, at least if it can, then that would be dramatically unexpected ;-)

## Define observer and survive (Score:1)

A human surviving forever in one piece? Or a single particle stuck in time? Or?

## No. Math doesn't show anything (Score:4, Insightful)

## Re:No. Math doesn't show anything (Score:4, Interesting)

People tend to believe that physics is applied math. It's not. The universe doesn't care about your math. General Relativity is a set of mathematical equations that were picked because they could model the observed experimental data.

The problem here isn't the mathematics or whether it applies to physics - or to reality, for that matter. The real problem is people's lack of insight - including many physicists. Take for example the idea of determinism - naively, this means that everything is pre-determined from some set of equations, which are assumed to have unique, well-defined solutions; but we already know of many cases where seemingly simple sets of equations behave chaotically. Now, I know well enough that mathematically, 'chaos' only means that a dynamic system is extremely sensitive to initial conditions, but since our understanding of quantum mechanics seems to indicate that we can't fix initial conditions of any system with arbitrary precision, there must be a limit to how deterministic any set of deterministic equations are in practise.

The point I'm making here isn't really about whether either GR or QM are 'true' or model reality correctly - we already know they don't - but the fact that we know far too little to make sweeping statements about anything as profound as determinism and causality. Apart from that, I can't see that this new calculation concerning certain types of black holes says anything of the sort; time and causality are strictly local - time experienced being the path integral of something or other in the 4-dimensional space-time manifold - and whether you travel in a closed loop or otherwise pass through events (~ 4-dim points in space-time) that you have passed before, the time you experience is still only your own, individual, highly local time, which does not necessarily have much to do with the rest of the universe.

A final point: mathematics is true - it is the only science that can claim to be absolutely tru, but the price we pay is that it is only true within its set of axioms. What this means is that as long as the axioms of any theory in the empirical sciences, match the reality we're trying to model, the conclusions of the theory MUST be correct - that is in fact the fundamental assumption behind the scientific method: it means we can falsify our assumptions by conducting experiments.

## Re: (Score:3, Interesting)

The point you are making is entirely moot.

Our current understanding of quantum mechanics already dictates that we live in an nondeterministic universe.

Quantum interactions are already expressed as probabilities and uncertainties.

Just look at nuclear decay. There is no way to mathematical model that can calculate when an atom will decay.

Hell, they can't even predict what will happen when you collide two particles.

You get several outcomes with different probabilities of happening.

## Re: (Score:2, Interesting)

Our current understanding of quantum mechanics already dictates that we live in an nondeterministic universe.

Our current understanding on quantum mechanics isn't necessarily correct.

It could be worth to consider that all measurements we have ever done on quantum level are with methods and equipment design with the assumption of determinism being true.

So quantum mechanics appearing to be nondeterministic causes a bit of a paradox.

If determinism is proven to be false then we can not rely on the the measurements that led us to believe that determinism is false.

Quantum mechanics being deterministic but extremely compl

## Re:No. Math doesn't show anything (Score:4, Interesting)

I am a physicist. This is not how quantum mechanics works. Probability and randomness are the result of measurement and not knowing the starting conditions. Should you completely know the quantum state (singular) of all the interacting particles in your system, you could exactly predict the outcome. Our change of "quantum state" to "quantum states" is useful to describe what we observe in the real world, but requires an assumption that the two "states" we're looking at are at some point separated by an infinite distance. This is a fine approximation, but not fundamental to physics.

## Re: (Score:1)

I am not a physicist, but doesn't this assertion rely on the hidden variables interpretation of the uncertainty principle, which has fallen out of favor? If there are no hidden variables, then the uncertainty pri

## Re: (Score:2)

In some cases testing such "edge cases" may also prove that certain aspects of a theory, how unintuitive they may sound, are necessary for an accurate model of reality. E.g. tests of the bell inequality show, that any theory that describes quantum phenomena must be a nonlocal one.

## Re: (Score:1)

## Black hole mysticism (Score:2, Informative)

Only difference between black holes and neutron stars is black holes overcome pauli and everything collapses into a shared state. Big whoop. Assertions of "infinite density" are nonsense. There is no evidence single massive shared states have exactly zero extent or that length is not quantized and energy sure as heck is not infinite so jumping to "infinite density" conclusions is premature at best. Neither is there anything special about escape velocities approaching C. Of course there are effectively

## It's The Mandela Effect! (Score:4, Funny)

Those experiencing it claim the past really did change and it's not their faulty memory. It's name comes from them remembering Nelson Mandela dying in prison in the 80's. [alternatememories.com]

## Re: (Score:2)

There was a great new X-Files episode about this. No spoilers, but it reimagined quite a bit and it was hilarious.

Info, with spoilers:

http://www.vulture.com/2018/01... [vulture.com]

## Eureka! (Score:2)

All those parking tickets:

gone!## determinism, a fundamental feature of the universe (Score:5, Insightful)

... determinism, a fundamental feature of the universe ...

While we may wish for determinism, it has been shown long before that it does not exist.Since it was shown that we can not accurately know both the position of a particle and its speed, it has been proven that predicting the future is impossible

because it is impossible to know the present, let alone calculate the future by using the present as a starting condition. So determinism is absolutelynota feature of the universe.## Re:determinism, a fundamental feature of the unive (Score:5, Interesting)

Not quite, e.g.: https://en.wikipedia.org/wiki/Superdeterminism

## Re: (Score:2)

While we may wish for determinism, it has been shown long before that it does not exist.Since it was shown that we can not accurately know both the position of a particle and its speed

This is just pure common sense sprinkled with a slight bit of meta physics. We know this is true for now because all methods of taking these measurements you describe involves "bumping" the particles in question thus changing their state. In order to truly know the state at some fixed time, we would need to plug into the back-end of the system from outside of it and to our knowledge this is impossible. From a software developer's perspective, this is akin to being able to write something directly from th

## yes and no (Score:2)

## Re: (Score:3)

Just to nitpick: thr fact that we can not measure the present does not mean that the future is not deterministic.

The particle you measure will go where it goes, unless you measure it. Then it is going where your measurement is deflecting it to.

## Re: (Score:2)

Just to nitpick: thr fact that we can not measure the present does not mean that the future is not deterministic.

The particle you measure will go where it goes, unless you measure it. Then it is going where your measurement is deflecting it to.

That is one way of thinking about how the universe *might* work.

Another way to think about it is a particle exists in a superposition state of many positions (each with their own probability), and it will effectively go everywhere, until you measure it and then all the things that it has interacted with in the past and transferred momentum to (even if they are now far away) are adjusted to be consistent with your current measurement.

Although you might think the second way of thinking of how the universe mig

## God is dead (Score:2)

## Re: (Score:2)

## Will wait for PBS SpaceTime (Score:1)

To cover this ( if valid they no doubt will) already have a collection of blackhole episodes

https://m.youtube.com/results?q=space%20time%20black%20hole%20&sm=1

## History Eraser Button (Score:2)

## Who reads this stuff?? (Score:5, Informative)

## Re: (Score:2)

Thanks for saving the Slashhive hundreds of hours of lost time.

Wait, did you erase a potential past? ;)

## I like it! (Score:2)

With my past destroyed, the one where I *didn't* enter a future-granting black hole and lived a mundane human life didn't happen.

Infinite futures means that in one of my futures, benevolent aliens gave me two cloned Jessica Alba sexbots.

WOO!

Do I get to tell people I had a threesome with Jessica Alba now?

## Noooo! (Score:2)

and result in the destruction of the observer's past and present them with an infinite number of futures.

Nooooo!!!

That's just what they

wantyou to think!Don't get on the carousel [wikipedia.org]!!!

## There must be laws (Score:1)

## Berenstein Bears and the black hole! (Score:2)

Berenstein Bears and the black hole!

## Re: (Score:2)

Berenstein Bears and the black hole!

The Berenstain Bears and the Wishing Star [wikipedia.org] (the strong cosmic censorship edition)

When Sister does some math on black hole event horizons, she loves it and wants to understand the implications concerning the cosmic censorship hypothesis [wikipedia.org] . That night, Mama reads Sister a paper about "Quasinormal modes and Strong Cosmic Censorship" [arxiv.org]. Sister wishes that the basic Photon sphere mode of a black hole is consistent with SCC and the wish comes true. Next she learns about pure de Sitter modes and wishes they are consi

## Debby Downer (Score:2)

Just to put a damper on discussions...

1) "theoretical black holes", meaning they may not exist naturally. If they do, they could be rare. At any rate travelling to any of them in the near future is impossible.

2) If one were to say artificially construct one of these things, in order for it to be big enough to fit a human though, it would have to be at least a certain size. A casual search indicates that a 5m event horizon black hole will have the approximate mass of Jupiter. So if it is constructed anywhere

## So, it's Control-Z (Score:2)

Or for the more sophisticated among us, Command-Z.

## nevermind...forgot to carry the 1 (Score:1)

oops, sorry about that.

## OK then, (Score:2)

Wish you all the happiness you deserve!

DT arrives at the pearly gate to enter heaven. Trumpets sound, the gates open and he is guided by two huge angles on his side to the throne with the almighty god.

God addressed DT and asks: "Do you have anything to say to me?".

DT: Ah, you are the guy sitting in my seat, get out!

## Bubble universes? (Score:1)

Sounds to me like they are describing movement to a different bubble universe, where you did not exist before. The math is incomplete, though, so it is not includng the bounds of the previous universe. Your history probably still would exist there.

I wonder if their math encountered the square root of minus one? That usually indicates that there are other dimensions/degrees of freedom that were not taken into account.

## fixing mod mistake (Score:2)

oops

## I think the solution is... (Score:2)

That getting to the event horizon takes an infinite amount of time. So it will never occur. Hawking radiation will make the event horizon recede before you can get there anyway, and probably kill you in the process.

## Re: (Score:2)

Sure, but GPS wouldn't work (or rarher, would be simpler) in that case. The weirdest things in the universe are proven by your phone existing.

## Re: (Score:1)

If you think everyone else is stupid, you probably have it backward. A lot of that going around these days... 8-)