Black holes and scientific standoffs

Yes, the Holographic Principle. A hologram is a two-dimensional sheet, such as film, which codes three-dimensional information. A simple way to say it is that the black hole horizon is like a hologram. The horizon of the black hole is like the film, and the image is the stuff that falls into the black hole. It's extremely unintuitive. According to this theory, the exact description of a region of space -- no matter how big -- is like a film on the boundary, where complicated and extremely scrambled versions of that space are going on. So in that sense, the universe is like a hologram.

Stephen now agrees that the information is not lost when a black hole evaporates.

Yes, he's seen the light. When he sees the light, he's very magnanimous.

[Susskind pointed to a page in his book, where a concession letter from Hawking is printed.]

Are there are any evaporating black holes in our region of the universe?

No. They are all accreting [still eating]. Black holes are much, much colder than their surroundings in space. That means heat flows from the surrounding space into the black hole. If we wait for a long, long time, the universe will expand, it'll cool, and eventually empty space will become colder than the black holes. When that happens, they will start to evaporate. But don't hold your breath.

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john.johnson@latimes.com