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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."
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!
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.
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.
That's correct. On a 1-stellar mass black hole, the tidal force across a human body at the event horizon would shredded well before you get to the event horizon. But on a supermassive black hole, no such thing would hapen.
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.
Fortunately, in physics, nearly everyone posts a manuscript version on arxiv.org (i.e. the same article but with the authors' own formatting, rather than the journal's layout). And indeed that is the case here.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
"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
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
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.
"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!"