Stephen Hawking's New Black-Hole Paper, Translated: An Interview

Stephen Hawking's New Black-Hole Paper, Translated: An Interview(blogs.scientificamerican.com)

59 points by softdev12 10 years ago | 13 comments

mattlutze 10 years ago |

This paragraph really nailed it for me:

"We show that when a charged particle goes in, it adds a soft photon to the black hole. So it adds hair to the black hole. And more generally if any particle goes in—because all particles carry mass and are coupled to gravity—they always add a soft graviton. So there’s a kind of recording device. These soft photons and gravitons record information about what went into the black hole—infinitely more information than we previously believed is recorded by this mechanism. Now whether all information is recorded by this mechanism… I'm pretty sure the answer to that is no, but there are generalizations of this mechanism and then it’s a lot more confusing."

They're showing in this model that perhaps, the event horizon of a black hold acts like this kind of abacus, pushing the photons suspended at the edge of the horizon a little bit in, a little bit out, recording what has fallen over that horizon during the life of the black hole.

That's really, really cool.

MikeNomad 10 years ago |

Maybe a Black Hole destroys information, or perhaps it changes information to a form that we can't (yet) recognize. Presently, both of those states would look the same to us.

kamilner 10 years ago | |

Did you have something specific in mind? Otherwise as I read your comment I should mention the 'recognizability' of the information is irrelevant to the paper. The paradox is about the differing predictions from general relativity and quantum mechanics, one of which implies that the information is lost and the other of which implies that the information is not (the form it takes is not important).

agumonkey 10 years ago | |

I was wondering this about empty space / dark matter. Maybe it's just we're blind to it so far, because assembled in a context of things sensitive to a specific blend of forces.

xyzzy4 10 years ago |

My first question is, how much of this is provable, and how much is conjecture?

lumpypua 10 years ago | |

This is a wrong-headed question to ask about theoretical physics. People have this idea that you can just say crazy physics things and they might be true, but that's not even close to the case. If you want to reach the level of conjecture, there are some incredibly high hurdles to pass. Your conjecture has to be consistent with both—both general relativity and quantum mechanics, probably the two most experimentally accurate and successful scientific theories in the history of the human race.

Here's a great lecture on this question of "well don't we need experiments? Is this all crazy physics conjecture?"

http://www.cornell.edu/video/nima-arkani-hamed-philosophy-of...

Black holes are the phenomena where quantum mechanics and gravity collide most intensely, and even theories of black hole physics compatible with both GR and QM are major achievements.

Edit: Although I agree the article is fairly opaque.

bcook 10 years ago | |

Does it matter? Theoretical physics is more of a game of logic rather than facts.

Edit: I apologize for being argumentative. Your question is somewhat intrinsic to the foundation of theoretical physics; given what we "know" now, what else can we logically deduce? There is no absolute answer, but that is part of the fun. :)

ars 10 years ago | |

All of it is conjecture.

That's one way to do physics: You start with conjecture and try to find ways to prove it. (You can also do the reverse, find some unexplained thing and derive rules.)

In this case it might be millennia before we can prove it though.

frozenport 10 years ago | |

You can simulate the equations [1] and debate if it matches observed objects.

http://arxiv.org/pdf/1601.00921v1.pdf

ars 10 years ago | | |

That would be tough since we've never actually observed an event horizon. We don't know if they even exist.

The only observations we have are of supermassive objects. Do they have event horizons? We assume so, but no one really knows.

martijn_himself 10 years ago |

I find articles like this both incredibly interesting but perhaps even more confusing.

It must be because the complex math underlying these findings can not accurately be expressed in human language.

mattlutze 10 years ago | |

The further down the theoretical rabbit hole you go, the more so even high-level discussions probably need a general comfort with the field.

Discussion about these soft particles, zero-energy photons and gravitons, being added to a vacuum changing its state out to infinity is pretty fascinating. I would have liked him to explain a little more in-depth how one of these particles could have no energy but still have a spin, though I imagine that's left to the reader to go find the papers that define it.