Nature’s cosmic hard drive? Black holes could store information like holograms

Enlarge / New research suggests we really can describe black holes as holograms: they have two dimensions, in which gravity disappears, but they reproduce an object in three dimensions. (credit: Gerd Altmann for PIxabay)

Nearly 30 years ago, theoretical physicists introduced the "holographic principle," a mind-bending theory positing that our three-dimensional universe is actually a hologram. Now physicists are applying that same principle to black holes, arguing in a new paper published in Physical Review X that a black hole's information is contained within a two-dimensional surface, which is able to reproduce an image of the black hole in three dimensions-just like the holograms we see in everyday life.

Black holes as described by general relativity are simple objects. All you need to describe them mathematically is their mass and their spin, plus their electric charge. So there would be no noticeable change if you threw something into a black hole-nothing that would provide a clue as to what that object might have been. That information is lost.

But problems arise when quantum gravity enters the picture because the rules of quantum mechanics hold that information can never be destroyed. And in quantum mechanics, black holes are incredibly complex objects and thus should contain a great deal of information. As we reported previously, Jacob Bekenstein realized in 1974 that black holes also have a temperature. Stephen Hawking tried to prove him wrong but wound up proving him right instead, concluding that black holes therefore had to produce some kind of thermal radiation.

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