![]() There's no getting rid of the electromagnetic field and other fields. It is not a region that is empty of everything. It is a region of space that is empty of particles. To the infalling observer, space looks like a vacuum, and in quantum theory, a vacuum is a very special state of affairs. Step #2 is to relate these two viewpoints. All the stuff piling up at the horizon forms a ghostly membrane, which obeys the usual laws of physics and has conventional properties such as viscosity and electrical conductivity. Because of a kind of gravitational mirage, things seem to slow down and freeze in time. Indeed, this observer never sees anything actually cross over. As they say, it's not the fall that kills you it's the sudden stop at the end.Īn outside observer knows you're doomed, but likewise doesn't think anything untoward happens upon passing through the event horizon. One of Einstein's great insights was that observers who are freely falling-whether into a black hole or toward the ground-don't feel the force of gravity, since everything around them is falling, too. But nothing noticeable should happen at the moment of crossing. By then, falling at nearly the speed of light, you have a few seconds to look around before you reach the very center and get crushed into oblivion. Once inside, you are gripped too tightly by gravity ever to get back out. Its perimeter or "event horizon" is not a material surface, but just a hypothetical location that marks the point of no return. According to current theories of physics, a black hole is mostly just empty space. Step #1 of the argument is what Polchinski and his co-authors call the "no-drama" principle. Polchinski's talk to the New York University physics department drew a standing-room-only crowd, not a single person snuck out early, and he was still fending questions an hour after it ended.Īlmost as much has been written about Hawking's original paradox (including by me) as about the fiscal cliff, so I'll jump straight to the new version. ![]() Polchinski blogged about it a few months ago, and another theorist who helped to usher in the idea, John Preskill, did so last week. I first heard about their brainstorm while visiting the Kavli Institute for Theoretical Physics in Santa Barbara this spring, and the team-Polchinski and fellow Santa Barbarans Don Marolf, Ahmed Almheiri, and James Sully- wrote it up over the summer. Polchinski and his colleagues have shown that the predicament is even worse than physicists used to think. The worst trouble is the black hole information paradox that Stephen Hawking loosed upon the world in 1976. Black holes are where the known laws of physics come into their most direct conflict. They are just insanely curious about what would happen. It's not because they have some peculiar death wish or because science funding prospects are so dark these days. In chatting with colleagues after a talk this week, Joe Polchinski said he'd love to fall into a black hole.
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