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How an Astronaut Falling Into a Black Hole Would Die Part 2
First time accepted submitter ydrozd writes "Until recently, most physicists believed that an observer falling into a black hole would experience nothing unusual when crossing its event horizon. As has been previously mentioned on Slashdot, there is a strong argument, initially based on observing an entangled pair at the event horizon, that suggests that the unfortunate observer would instead be burned up by a high energy quanta (a.k.a "firewall") just before crossing the black hole's event horizon. A new paper significantly improves the argument by removing reliance on quantum entanglement. The existence of black hole "firewalls" is a rare breakthrough in theoretical physics."
The only new information cited is behind a $25 pay wall. Kill it with fire.
From the arxiv: http://arxiv.org/pdf/1307.4706.pdf
It's not the fall that kills you, it's the sudden ...oh wait, it IS the fall that kills you.
He'd die of old age.
The nearest black hole is 1600 light-years away. If our astronaught started to journey thence, at the beginning of the Bronze age, it would be conceivable that he'd arrive there sometime in the next couple hundred years - using the fastest of feasibly extrapolated propulsion technologies. This of course, supposing those could have existed after the retreat f European ice-sheets.
Any other planned method to acquire more rapid proximity to a black hole, probably wouldn't work out, either...
"Flyin' in just a sweet place,
Never been known to fail..."
I love how we treat blackholes specially.
The escape velocity of a neutron star is about 1/3 the speed of light --- and getting mass to 1/3 the speed of light is absolutely impossible.
Escape velocity from the Sun is 617 km/per second --- not even New Horizons at 35,000 kph is anywhere close to that!
Jupiter's escape velocity? About 60 kps --- so if New Horizons was 8 or 9 times faster, would match that.
But black holes --- are not especially dangerous to humans in any way that any other massive objects (gas giants included) aren't. For some reason, we teach kids and adults that blackholes are "evil" and suck up everything --- but blackholes are very helpful holding galaxies together and binding our galaxies together so that they are warm and stable for extremely long periods of time.
Without blackholes, the universe may not be able to support life without the stability that blackholes give to galaxies.
So quit dogging our friends, the blackholes, you insensitive jerks!
Priest: "Universe from nothing, no laws of physics, sped up time"+ huge discrepancies. Creationism? No. Big Bang Theory
The funny thing is . . . if someone announced a space program to toss an astronaut down a black hole . . . there would be plenty of volunteers for the mission.
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
It's the gravity. You're actually seeing one "would", but the gravity bends light around that you see it again in a different apparent position.
I love how we treat blackholes specially.
Why shouldn't we? They're extremely interesting.
For some reason, we teach kids and adults that blackholes are "evil" and suck up everything
At least that's less wrong than declaring that:
getting mass to 1/3 the speed of light is absolutely impossible.
systemd is Roko's Basilisk.
Black hole firewalls don't really exist.
Here's a summary:
http://arxiv.org/abs/1310.6334
and the long paper:
http://arxiv.org/abs/1310.6335
Resolving the issue.
In short, the black hole paradox doesn't exist and can be explained.
Motl has a really nice summary as well:
http://motls.blogspot.com/2013/10/raju-papadodimas-isolate-reasons-why.html
A black hole would eventually stretch a person into spagetti, but not necessarily near the event horizon. For a small black hole the effect might be well outside the event horizon while for a supermassive black hole the effect would be well inside of it.
This is because the event horizon of a super-massive black hole is so large that while the gravitational pull there is enormous, the variation in the graviational forces in a human-sized volume is quite small. It's the variation in the forces that stretches you.
Likewise, while the total gravitation pull well outside the event horizon of a small black hole is much less than the total gravitational pull near the event horizon of a super-massive one, the variation is much higher.
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The nearest black hole is 1600 light-years away
Famous last words...
If Pandora's box is destined to be opened, *I* want to be the one to open it.
Interstellar racism, you think?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
I don't agree. If you assume he is 1.5 meters high, then the relative forces at the event horizon would be minimal, remember it is over r^2. The Schwarzschild radius as it is called. If you took our sun's mass and converted to to black hole densities, it would be r of 2,950 m. Now, the force at this even horizon would then be 2950m and 2951.5m Find the tidal forces over that 1.5 meters. It's not a whole lot. However you start to get into time dilation, again over 1.5 meters it isn't that much.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
FTFY: and getting mass to 1/3 the speed of light is currently impossible
Actually, it's very possible; about every accelerator in the world does it regularly.
Having said that, getting a macroscopic mass to 1/3 the speed of light is currently impossible. Well, at least when considered from the frame of reference in which it originally was at rest.
The Tao of math: The numbers you can count are not the real numbers.
hey man...good thoughts...
I think I might have some answers...
It seems, and this research bolsters the idea, that the Event Horizon obliterates **everything** and scatters the energy across the event horizon. Anything like "Hawking Radiation" then becomes just another result of the Event Horizon obliterating matter. The characteristics (information) of the matter (speed, mass, velocity, spin, charge, etc etc) are truly completely obliterated at the Event Horizon.
In this way, *nothing* ever actually crosses the Event Horizon. The 'Black Hole' then functions as a perfect 'black body'.
This view has repurcussions across physics. If what I say is true, then essentially, Black Holes could be viewed as bubbles in the Quantum Foam of the universe. Which means the universe ends in heat death.
Thank you Dave Raggett
Well, the firewall rules for a black hole are easy: You let every packet in, but none out.
The Tao of math: The numbers you can count are not the real numbers.
The nearest black hole is 1600 light-years away
That's the nearest one that we can see. However we only detect them by seeing emissions from the matter which falls into them. There could easily be one nearer that is nowhere near any matter. The only way we would then be able to detect it is by its gravitational influence on the solar system.
However, regardless of this, if you actually made it to a Black Hole the tidal forces would rip you apart well before you close enough to worry about massive time dilation effects. The closer you get to the black hole the stronger the field which means that, assuming you went in head first, the gravitational pull on your head would be a lot greater than the pull on your feet...you can imagine what the result will be when this force difference becomes large enough.
Black holes are the sharks of space. Despite of being thousands of times less probable to die because of sharks than because (directly or indirectly) of cars the culture is only afraid of sharks. The end of mankind will more probably come from down here than from up there.
True, but in any scenario at all this is about what would happen to his corpse.
Free Martian Whores!
Having said that, getting a macroscopic mass to 1/3 the speed of light is currently impossible. Well, at least when considered from the frame of reference in which it originally was at rest.
Where are the mods? +5 insightful. Note: currently impossible. Look at how primitive things were just half a century ago.
Free Martian Whores!
You just quoted WUWT in a scientific discussion with a straight face?
First off, New Horizons is travelling at 35,000 MPH, not kph. Second, those escape velocities would be at the surface of the body for unpowered bodies. Escape velocity decreases with distance from the body. It's possible to simply accelerate directly away from an object and never reach speeds anywhere close to escape velocity, until you are far enough away that you have simply exceeded (that now much lower) escape velocity threshold. So I'm not sure what point you're trying to make.
Better known as 318230.
"Well, the thing about a black hole - its main distinguishing feature - is it's black. And the thing about space -- the color of space, your basic space color -- is it's black. So how are you supposed to see them?" - Holly
"and getting mass to 1/3 the speed of light is absolutely impossible."
Isn't that done in particle accelerators every day?
In the land of the blind, the one-eyed man is king.
So the flying spaghetti monster could, one day, be for real...
It was created when a walking lasagne monster got too close to a black hole.
Sheesh, evil *and* a jerk. -- Jade
Of course space isn't really black; rather it is completely transparent. It's the cosmic horizon behind it which is black. Actually at the horizon there's the glow of the big bang, but it is so heavily red-shifted that we only see it in the microwave range (the cosmic microwave background). Now in principle, when looking in the microwave range, black holes should be detectable as "microwave shadows". However I don't think we can measure microwaves in sufficient angular resolution for that.
The Tao of math: The numbers you can count are not the real numbers.
Find the tidal forces over that 1.5 meters. It's not a whole lot. However you start to get into time dilation, again over 1.5 meters it isn't that much.
Really now. And how did you arrive at it not being "a whole lot"? Let's insert some numbers, shall we? The mass of the sun is about 2e30 kg. Its Schwartzschild radius is, as you say, 2950 km. The acceleration according to Newtonian gravity at that point is 1.5211095e13 m/s^2. 1.5 meters further out (that's a short astronaut, by the way), the acceleration is 1.5195660e13 m/s^2. The difference is 2.057e10 m/s^2. I.e. roughly 2 billion g. Most of us would find it hard to stay together under such tension, but I guess you're made of stronger stuff!
(Of course, Newtonian gravity doesn't work very well for such strong gravitational fields. But it's enough to tell you that you're in a lot of trouble.)
No he wouldn't. With an acceleration of 1g you can reach the edge of the visible universe in a mere 40 years due to time dilation. A nearby black hole would take much less time.
See http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html
If our astronaught started to journey thence, at the beginning of the Bronze age, it would be conceivable that he'd arrive there sometime in the next couple hundred years
Nitpick: thence, hence and whence denote movement from, whereas thither, hither, and whither denote movement to. The astronaut would have to already be there to start a journey thence. Compare the well known expression "go back whence you came".
Given the rarity of these terms in modern English, I believe it is safe to assume that anyone using them is attempting to speak correctly with an air of erudition, which is why I have tried to bring this to your attention, even if this comment will likely be buried by downmodding.
Of course space isn't really black; rather it is completely transparent.
Of course you are correct that it's not black. However, it's also not "completely transparent". It's "mostly transparent". There are stray atoms and molecules wandering around, and even gigantic clouds of gas and other matter, which all scatter light and other radiation.
If we're going to be real, then let's be real.
So the best answer on how an astronaut will die is "like the rest of mankind"?
I think the best answer is that the astronaut would die of humiliation, because of all the laughter from the other astronauts for falling into a black hole.
Yes, but what happens to the information in the packet - is it destroyed or not?
I have left slashdot and am now on Soylent News. FUCK YOU DICE.
Thanks. I must have messed something up with the exponents. 2 billion g is a lot of G.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
Unless the argument is that a black hole can sustain a a dense field of sub-atomic particles in high speed orbit near the event horizon in a toroidal form collapsing at the poles. So the answer to what happens to an astronaut who falls into a black hole, well, that depends upon whether it is near the black holes equator or it's poles.
Chaos - everything, everywhere, everywhen
"Look at how primitive things were just half a century ago."
Like Slashdot 1.0?
My understanding/way I imagine it is that; as you move towards the blackhole, the particles that make up the astronaut cause the event horizon to come out to meet them, and this curves the event horizon and this causes a local burst of Hawking-type radiation that rips apart the astronaut, and this radiation spreads out from the impact point in a wave; that in turn creates more perturbations of the horizon and so on. You end up with a very thin ring of fire all around the black hole. And this never goes away; indeed it forms the moment the black hole does, and so there's actually nothing inside the blackhole, just flat spacetime. In a sense I suppose the collapse never completely happens you end up with just a shell of matter.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!""black holes have no hair"
If they have no hair you can't split their hairs.
Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
Hawking radiation is produced when vacuum fluctuations near the event horizon produce a particle pair, one of the two fall in, and the other escapes. In order to make the process make mass-energy sense, the particle that falls in is more probably the antiparticle of the pair so that the BH supposedly emits normal matter and decays. For tiny/microscopic black holes this process is supposedly extremely rapid so that they "evaporate". For "large" BHs, it takes so long that one can nearly ignore the process compared to e.g. the influx of ordinary matter.
However, Hawking has been shown to be wrong in a lot of his original work on this theory -- or rather, the theory has been shown to be inconsistent with Quantum Mechanics -- and the real entropy increases associated with this sort of process or the process of ordinary infalling matter have been shown not to exist. Leonard Susskind's book The Black Hole Wars: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics walks you through all of this at the accessible-to-normal-humans level (as opposed to the level of QFT/String theory, which he also does elsewhere).
All pretty heady stuff, of course. Theorists can really go to town when the nearest known potential physical realization of an idea is order of 10^22 meters distant and only visible at all from synchrotron radiation from infalling charged particles emitted some distance away from the supposed event horizon. But I do agree that a TOE needs to be conservative of quantum information at least until we reproducibly and believably observe a direct violation of this principle somewhere.
rgb
Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
Is that anything like the difference of "all dead" and "mostly dead"?
Sheesh, I'm sure you're the type who'd think that some poor heartsick idiot's sole reason for existing is "To blave."
You are forgetting length dilation in the moving frame of reference, and so have it all wrong. Length and time dilation have the same Lorentz transformation factor, so you can either think of it as time moving more slowly for the traveller from the outside viewer, or the distance being shortened from the traveller's perspective. Either way, the traveller could make the trip in 10mins with sufficient velocity/energy, as the original commenter said.