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How Would an Astronaut Falling Into a Black Hole Die?
ananyo writes "According to the accepted account, an astronaut falling into a black hole would be ripped apart, and his remnants crushed as they plunged into the black hole's infinitely dense core. Calculations by Joseph Polchinski, a string theorist at the Kavli Institute for Theoretical Physics in Santa Barbara, California, though, point to a different end: quantum effects turn the event horizon into a seething maelstrom of particles and anyone who fell in would hit a wall of fire and be burned to a crisp in an instant. There's one problem with the firewall theory. If Polchinski is right, then either general relativity or quantum mechanics is wrong and his work has triggered a mini-crisis in theoretical physics."
Locate a black hole and start shooting monkeys at it! "Science can not progress without heaps [of monkeys]"
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
The /. I knew and loved a decade ago is gone.
Hell is in the black hole. And pray you don't go there with a psychotic red robot.
TFA is an interesting article about a physicist apparently discovering an inherent contradiction between general relativity and quantum mechanics. The "black hole" stuff is really just the context that led to the apparent contradiction: the real issue is much deeper than that. It's depressing that the real underlying hypothesis isn't considered newsworthy, and the editor feels the need to lead with the "black hole" stuff.
[Sir Garlon] is the marvellest knight that is now living, for he destroyeth many good knights, for he goeth invisible.
Have gnu, will travel.
i agree the reversed lower playfield can be a bit disorienting at first, but let's not get melodramatic -- since there are no outlanes in the gravity well, a quick SDTM drain is really the only way to die down there, and completing either bank of drop targets opens the re-entry gate anyway.
i could live a little longer in this prison
Yes, because getting to a black hole will take a long time.
Unicorns would stampede the astronaut as he enters the event horizon. There's one problem with the unicorn theory. If I'm right, then either general relativity or quantum mechanics is wrong.
Heck, considering what we know about the environments around black holes, not only will the gravitational tides kill you before you reach the event horizon, so will the radiation.
Everybody repeat after me: "Black holes ain't yer friend. Don't try to hug them, you will die."
The /. we all knew and loved a decade ago was gone by 1997.
try to avoid falling into a black hole
JADBP
well, technically, wouldn't the convicted murder BECOME an astronaut by definition the moment we shot him into space?
slashdot is really provoking the deep questions today.
i could live a little longer in this prison
The other way around: The universe dies of old age around the astronaut and black hole.
I thought that black holes were still theoretical. Or have they been scientifically proved, and I'm just an asshat?
They've been observed - just because there's theoretical work being done about something doesn't mean it hasn't been shown to exist.
Leave your crappy sitcom references at the door and let the adults talk.
Take the time to read too, you might learn something that isn't some comic book fantasy.
Besides, if anyone knows the answer, it's Dr. Hans Reinhardt.
This isn't true.
QM and *special* relativity get along just fine. When you combine them in a simple way you get predictions like antimatter, the fine structure of the hydrogen atom, and so on. If you do this in a more detailed way, using quantum field theory, you get the fantastically accurate predictions of quantum electrodynamics, the theory of quantum chromodynamics that can't be solved with pen and paper but which still gives accurate predictions when done on supercomputers, and so forth.
And there's nothing forbidding QM from playing nice with general relativity, either; we just don't know how it works yet. There are some models, like lattice quantum gravity, that seem quite promising.
How would he die?
Of old age, on the multimillion year journey to the nearest black hole, I suppose.
But don't let me be the one to interrupt your little rec time, on the holodeck. ;-)
"Flyin' in just a sweet place,
Never been known to fail..."
If the astronaut gets across the event horizon, then he will never die relative to us. So, there really isn't a problem here as far as I can tell.
Umm... He's a string theorist, so...
Listen to Zombie Feynman kids: Unscientific:
It must have been something you assimilated. . . .
There was an SF short story in which an interstellar alien being was psychically-linked with a human and was helping her team study a black hole. The alien is unable to escape the gravity well and is quickly destroyed. Unfortunately, for the human, the alien's time frame is different, so the human will experience its psychic scream for her entire life.
Yes, black holes have not only been observed, but super-massive black holes have been discovered at the center of every galaxy we've checked.
Give me Classic Slashdot or give me death!
You got that exactly backwards.
Refer to Stargate SG-1 episode "A Matter of Time" (Season 2 Episode 16): "SG-10 is stranded on planet P3W-451, which is close to a newly formed black hole. The SGC opens the gate to find out what happened, but they cannot shut it down afterwards. Soon they realize that since the planet is near to a black hole, its intense gravity is causing time dilation, so if they do not shut down the gate very soon, it will destroy the SGC, and in time, the entire planet."
People outside the base have much longer to think about what's happening inside the base. e.g. At one point Hammond spends 18 hours off base while those inside the base think he was only gone for ~20 minutes.
Heck, considering what we know about the locations of black holes and the speed of manmade spacefcraft, old age will probably kill you before you get close enough to notice the gravity.
Everybody repeat after me: "Space is big. Don't mind Sarten-X, he is a jackass."
You do not have a moral or legal right to do absolutely anything you want.
They've found numerous stellar objects of various sizes that conform to the preditions of black holes. (Mass, diameter, etc) Though none have been directly observed, their 'feeding' does generate a lot of energy that is detected when something falls in. Just recently one that had been relatively quiet for some time gave of a nice 'burp' of radiation as it apparently 'ate' a planet.
:D
Have we been to a black hole? No.
Have we taken photos of an actual black hole? No.
Have we seen gravitational effects that look exactly like what a black hole should have? Yes.
Do those gravitational effects calculate out as something of several to millions of solar masses in a tiny volume that can't exist in any non-black hole way that we are aware of? Yes.
Have we seen the radiation from an accretion disk falling into and being destroyed by a black hole as predicted? Yes.
Is a black hole what astrophysicists think it is? Probably.
Is a black hole what non-scientists (hollywood, general public, dentists, etc) think it is? Probably not.
Do you really exist? This is about black holes, but your existence is only a bit less theoretical than that of a black holes, though some of the specifics of either may not be what is generally thought about them.
And no, a black hole is not god dividing by zero. It's more likely an alien mad scientist multiplying by the square root of negative zero.
Yeah, that sounds about right. The last time I read about this... somewhere... it really depended upon the size of the black hole.
Approaching a small black hole, the gradient in gravitational forces closer to the black hole means that e.g. diving head-first into a black hole would mean your head would feel a stronger gravitational pull than your feet and thus your body would be stretched and ripped apart.
Approaching a much more massive black hole with a larger event horizon could reduce that gravitation gradient enough. But of course you'll be much further from the singularity point as well.
Of course, both ignore the particle soup of other things falling into black holes that would surround most actual black holes.... which is what this article is considering. As well as the fact that it's pretty difficult to dive directly into a celestial object vs. falling into it via a gradually decaying orbit (which is what most of the particle soup is doing).
Also, someone say something about frame dragging effects near such large relativistically-moving amounts of mass.
The whole "what would happen to an astronaut" is the misleading sensationalist that's been pollution this site lately. It seems they're really going from "News for Nerds" to "Fox News for people who may buy computer and sciency stuff from places like Thinkgeek" (though thinkgeek is awesome BTW) in order to gain bigger audience.
End result is it drives away the core audience that used to make this site awesome, as it dumbs down the really interesting science parts beyond recognition.
Actually, it is also possible that there is no such thing as a black hole - but cetain parts of the universe just suck. I have known some towns like that.
"-1 Troll" is the apparently the same as "-1 I disagree with you."
He would die of shock [...] And then her body would be torn asunder.
So you think a black hole would accomplish a gender change on the subject? Interesting theory.
While yes, one of the things you would have to deal with is the incredibly hot material swirling around the event horizon which, in and of itself, should produce enough X-rays to fry you, I think this article is actually talking more about an actual characteristic of the event horizon, as opposed to what is in orbit around it, or even what is infalling.
In short, space is supposed to look the same to an observer no matter what side of the event horizon they are on. Instead, a special condition where you smack into something that is there beyond what you would expect from a black hole with infalling matter occurs. That "wall of fire" obviously consists of stuff that has entered the event horizon of the black hole, but it is structured in such a way as to form a highly energetic barrier that should not be there based on our current understanding of relativity or quantum mechanics.
This reminds me of the two unknowns: how can a black hole be created if the matter falling to it can never get there? The another one is of course: how can gravitons escape event horizon and attract anything?
I think good theorists can answer both - I cannot either.
That was when Slashdot IDs were negative numbers. Ahhh... I was so much older then, I'm younger than that now.
If you fall into a big enough black hole, you die by running out of air in your spacesuit.
Not only is the tidal stress less, but supermassive black holes tend to clear the vicinity of stuff, so if its not 'feeding' there is no radiation to fry you either.
First answer: Alone.
But I saw this rather interesting video of a lecture by Leonard Susskind : http://www.youtube.com/watch?v=pf0D8A0jRiY ;)
It will probably not answer your question, but it's about black holes and they're very cool! Or hot. Depending on the observer
Privacy is terrorism.
Don't worry, I can fix that...
Now, Wikipedia says "In addition, a convicted murderer shot through space toward a black hole for experimental purposes."
Nostalgia ain't what it used to be.
William of Ockham had no beard. The most likely explanation is that it was chewed off by squirrels every morning.
But that is pretty much what would happen according to all theory, that is what the idea was based on.
Most of SG series is based on working and partial theories, and a few controversial ones too. (like man vs machine consciousness in that life has soul where machine does not)
"astronaut" - Someone on who has gone into space.
"fall" - 'to descend under the force of gravity"
"Into" - "to the inside of"; Also "toward or in the direction of:"
"black hole" - "an object in space so dense that its escape velocity exceeds the speed of light"
"die" - "to cease to live; undergo the complete and permanent cessation of all vital functions; become dead."
Or possible in this case: "to cease to exist" literally.
"Ass" - You.
The Kruger Dunning explains most post on
And there's nothing forbidding QM from playing nice with general relativity, either; we just don't know how it works yet.
Translation: As currently formulated, at least one of quantum mechanics and general relativity is wrong, although like Newtonian mechanics or pre-relativistic optics, they will undoubtedly continue to be practical and very accurate approximations.
We knew this as soon as quantum mechanics was developed.
Perhaps you could cite what you are referring to. I know of no statement by Hawking that suggests gravity affects antimatter differently than matter.
The world's burning. Moped Jesus spotted on I50. Details at 11.
We know no such thing. In fact both appear to be true, the problem being that we don't have an overarching theory that explains how that is so.
The world's burning. Moped Jesus spotted on I50. Details at 11.
I don't understand. The standard view of antimatter is that gravity very much does affect it in some way equal to matter.
There are a few possibilities that need to be tested, such as if antimatter can cause antigravity in equal, but opposite proportion to how matter warps spacetime to generate gravity, or that antimatter might generate more or less gravity. However, this is only because we have yet to be able to test antimatter properly. The generally accepted hypothesis is actually that antimatter does affect gravity equal to matter.
The idea is that the two particles form, and one is closer to the black hole than the other. One of them barely falls in, while the other barely makes it out. No difference in how gravity effects them, just a difference in initial positions.
Actually this says that one member of the particle-antiparticle pair could fall into the black hole. It says nothing about which one would. Sometimes it could be the particle and sometimes the antiparticle. They are both treated the same by gravity. My understanding is that since the particle-antiparticle are separated by a tiny distance, sometimes one is inside the event horizon and is swallowed by the black hole leaving the other one to escape. Since they don't recombine, the one that is swallowed has negative energy causing the black hole to lose energy. Whether it's the particle or antiparticle is completely random, to the best of my knowledge.
un-ALTERED reproduction and dissimination of this IMPORTANT information is ENCOURAGED
Then why would the particle be affected differently than the antiparticle? Why wouldn't *both* fall into the black hole equally?
Both the particle and the antiparticle are affected equally by gravity, but gravity is the weakest force in nature. Think about it: a simple chair, held together by the electromagnetic force, supports you above the ground by counteracting the gravitational attraction of the entire Earth pulling you down.
Since virtual particle pairs start from vacuum, they are always created with equal but opposite momentum. This momentum can't be very big because the attraction between the pair (usually electromagnetic) has to be strong enough to quickly counteract that initial momentum (and bring the particles back together fast enough for them to still count as "virtual"). But just because the momentum can't be very big doesn't mean it can't be big enough for one particle to escape a black hole, if the particles happen to pop into existence with one of them pointing in just the right direction to escape. Hawking predicts that the odds are 50/50 on whether it's the matter particle or the antimatter particle that does the escaping; it has nothing to do with the particles responding differently to gravity.
(Keep in mind that the escaping particle doesn't have to rocket out in a straight line at escape velocity. Instead, it can take a few swings around the black hole in a rapidly decaying orbit, until it slingshots out on a hyperbolic path. The smaller the black hole gets, the more definite the position is for every matter/antimatter particle pair, and by Heisenberg's uncertainty principle applied to position-momentum, this makes it easier for one of the two particles to escape. A smaller black hole also has the bonus that, looking out from just above the event horizon, more directions point away from the black hole, giving more chances to escape.)
You could actually make a black hole that radiates away Hawking radiation with a bias toward antimatter over matter, or vice versa. It's easy: black holes can have an electric charge, so just electrically charge the black hole! Like charges repel, so if the black hole is positively charged, it will preferentially eject positrons instead of electrons. However, the absorbed electrons neutralize the black hole's electric charge, bringing it back to neutral and making the Hawking radiation return to a 50/50 ratio between matter and antimatter.
(We suspect that the universe has a small preference for matter over antimatter, and this is why the universe is made of matter. But this mostly happens for some heavy uncharged mesons, not for lightweight simple particles like electrons. Here, "heavy" means "high energy" means "unlikely to appear in Hawking radiation". So the radiation may not strictly be 50/50, but it should be very close.)
Range Voting: preference intensity matters
I think they were asking why the one that escapes is always the one that ends up with positive energy, i.e. we never get 'reverse Hawking radiation' sucking up mass from the larger universe and adding it to the black hole. I vaguely know how this works, but my layman's understanding of QM isn't good enough for a decent explanation, and I don't want to lead others down the wrong path.
Heck, considering what we know about the locations of black holes and the speed of manmade spacefcraft, old age will probably kill you before you get close enough to notice the gravity.
Everybody repeat after me: "Space is big. Don't mind Sarten-X, he is a jackass."
The trouble is that "what we know about black holes" is all theoretical and mathematical. No one has ever directly observed a black hole and thereby shown that these things even exist in the real world. Black holes were invented to explain present-day theories about the motion of stars and galaxies. The same is true of "dark matter" and "dark energy" and other dark fictions. Perhaps it is time to examine some of these widely held theories that require these mathematical fictions. At the center of these hypothetical, theoretical black holes is this mathematical entity that has been called a "singularity". This is another mathematical fiction that can't exist in the known universe.
Mathematics are very useful in describing measured experiments and observations in the physical universe. As soon as mathematics and computer simulations go beyond what is actually observed and measured, it no longer describes the real world were living in. Current cosmological theories are no better than those held by the majority of scientists in the days when everybody thought the Earth is flat and is at the center of the solar system and the universe. It is time for someone like Copernicus to bring these mathematical theorists back into the real world.
In 1929 an astronomer named Edwin Hubble discovered that "red shift" of distant galaxies. Then he made the assumption (belief, faith) about the cause of this observation. Astronomers still base their belief in the expanding universe on this assumption. Anyone who wishes to pursue this further can Google "Halton Arp" and "William Tift".
A sufficiently advanced simulation is indistinguishable from reality.
Ahem, where was I before the new Slashdot mobile interrupted me?
To an outside observer, time stops at the event horizon. Nothing can ever fall through it. Someone falling in would see the universe speeding up, faster and faster, until time was progressing at an infinite rate by the time he hit the event horizon. Presumably either the black hole would evaporate or the universe would end before the infinite amount of time passed necessary for someone to reach the event horizon.
I don't really see the problem - if the firewall exists, it's located in a region of space that is forever inaccessible.
Assuming you're not trolling, that's a nice story, but that's not how science works.
The trouble is that "what we know about black holes" is all theoretical and mathematical.
Usually, the first step in science is to observe something. In the case of black holes, our knowledge of their existence can be traced back to a few experiments, which provided pretty solid evidence against the prevailing theories of aether. The observation that doesn't match the expectation means that the theories aren't right, and must be changed.
In fact, many of today's experiments are simply re-running old trials, but with more precise technology. Rather than dropping rocks off a tower, we can measure how fast individual atoms fall, giving us a more exact understanding of gravity. Usually the results are a perfect match for what's expected, but sometimes they aren't.
Black holes were invented to explain present-day theories about the motion of stars and galaxies.
Next comes the theory. Starting from the results of those experiments, Einstein hypothesized his theories of relativity, which are really little more than a collection of relationships derived from the assumption that the speed of light in a vacuum is constant. His theories explained the results of previous experiments, and importantly, provided a set of formulas that can be used to make predictions for future experiments.
Mathematics are very useful in describing measured experiments and observations in the physical universe. As soon as mathematics and computer simulations go beyond what is actually observed and measured, it no longer describes the real world were living in.
The relationships in the physical world are described with mathematics. Sometimes, when math is insufficient to easily describe a particular relationship, new mathematical forms are invented to accommodate the real world. Ultimately, though, every physicist knows that the mathematical models do not prescribe reality, but describe our understanding of it. Again, we use those models to predict the outcome of future experiments.
At the center of these hypothetical, theoretical black holes is this mathematical entity that has been called a "singularity". This is another mathematical fiction that can't exist in the known universe.
That depends on the rules of the known universe. in 1915, Karl Schwarzchild transformed Einstein's theories of relativity into a form that would require black holes. This means that Einstein's formulas can only be correct if the universe allows black holes. If the universe does not allow black holes, then Einsteins formulas must be wrong - though less wrong than the aether theory they replaced.
Perhaps it is time to examine some of these widely held theories that require these mathematical fictions.
That's what experiments are for.
No one has ever directly observed a black hole and thereby shown that these things even exist in the real world.
Black holes have been observed many times.
In 1929 an astronomer named Edwin Hubble discovered that "red shift" of distant galaxies. Then he made the assumption (belief, faith) about the cau
You do not have a moral or legal right to do absolutely anything you want.
All so-called "discoveries" of black holes are attributed to their supposedly enormous gravitational effects on their surroundings, but they never themselves have been found. The same is true of dark matter. The link you gave is all about how the gravity supposedly affects the surroundings of a black hole.
http://www.cfa.harvard.edu/seuforum/bh_reallyexist.htm
ALL the observations in that article can be explained by the operation of a force 36 orders of magnitude greater than gravity. This force is electromagnetism as evidenced by cosmic plasmas that can be accurately modeled not only with computers, but with real physical experiments in the lab. Most of the universe is not nicely electrically neutral, like here on earth, but consists of highly charged electrically active plasma. Most atoms in the universe don't have all their electrons nice and neatly orbiting their nuclei.
Scientists are observing immensely powerful cosmic rays and other radiation from many sources in the universe. All this radiation involves the electric force and has nothing to do with gravity. Scientists have postulated that there should be gravity waves and have spent gobs of money to try and detect these, but so far that has been money wasted since they have not found such waves. In addition, there are measurements of immense magnetic fields in space and on the sun. It is a firmly established principle of science, that magnetic fields can be generated easily by the motion of electric charges.
The large-scale universe is controlled by electrical forces that are far greater than gravity. Gravity is only a controlling factor in electrically neutral environments such as we have here in our corner of the universe. Even if only one atom in 100 billion loses one of its electrons, the force generated by this tiny charge imbalance is far greater than the gravity generated by those 100 billion atoms. You can verify that by doing an experiment right in your own home. Just pick up a few bits of Styrofoam with a charged glass or plastic rod. Charge the rod by rubbing it with a silk cloth. The electric charge on the glass rod will easily overcome the gravity generated by the entire Earth.
A sufficiently advanced simulation is indistinguishable from reality.
Actually the thing that "crushes" the astronaut is the gravity differential over the length of the astronaut. In a "small" (let's say football-sized) black hole that difference is huge, and so the astronaut will get torn apart.
However with a supermassive black hole (and there's never been any other kind detected, they may exist briefly, but that makes the chances of encountering one very small), the differential at the event horizon is tiny.
As for the astronaut, you might think he might have trouble sending nerve impulses from his feet (beyond the event horizon) to his head (outside), however he's guaranteed to fall in faster than any signal can propagate outward, so this is not true. The astronaut will not notice anything (except -maybe- hawking radiation, which will be very weak for large black holes too).
So what do you see when you cross an (realistically sized, ie. huuuuuuuuuuge) event horizon ? Why ... nothing at all. You will see a very, very slight natural luminescence, probably deep in the radio frequence (ie. not visible). Everything will still look normal, exactly like it looked before.
There is also a reason why black holes "look like" the end of time. What does an outside observer see when you fall into a black hole ? Well he sees you slow down, due to time slowing down. An outside observer will never see you actually cross the event horizon, and whatever light you reflect you will reflect "slower" the closer you are to the even horizon. So the light reflecting off of you will fade, but very very slowly. Even hundreds of years after you fell into a black hole, a very sensitive telescope will still be able to construct an image of you and it remains theoretically possible until the end of time (it's going to become damn hard though).
There is also the question of what exactly the edge of the universe is. Objects near the theoretical edge of the universe move away from us at nearly light speed ... which might be what you'd expect to see if these were objects that had just fallen through an event horizon. It makes a kind of sense. The edge of the universe is moving away from us at light speed, but a large black hole would pull in exactly enough space so that any light moving away would travel the distance, and yet still remain just inside the event horizon.