Stephen Hawking said something! And again the international media is all a'buzz.
The physics community is a little more muted, but after hearing the pronouncements of the famous theoretical physicist, of supertranslations and horizons, like those listening to Douglas Adams’s Deep Thought, you might be wondering what the actual question is.
We don’t have to go far, as a little over a year ago I wrote about Hawking’s previous proposed solution to the same problem, namely the paradox of information and black holes.
All About the Information
As a quick reminder, the core issue is the apparent forgetfulness of black holes. Black holes can swallow anything that comes too close, squashing all matter into the apparently point-like singularity on the way.
Only a few properties of the infalling material are remembered, imprinted on the black hole’s gravitational field, namely the mass, the charge and the angular momentum. All other properties appear to be promptly forgotten; neglecting spin and charge, all black holes of the same mass are identical, whether they were built of collapsing stars or from an immense number of tennis balls.
This “no hair“ of black holes, telling us that they can only remember the mass, spin and charge of infalling objects, has been known for half a century.
