Slashdot Mirror
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
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
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.
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
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.)