Skip navigation

Tag Archives: event horizon

There is a typographical error on p. 363, column 1, second line from the bottom, when referring to the event horizon: ‘1/3’ should be ‘2/3’ in the sentence:
“Its radius is exactly 2/3 times that of the photon sphere, or 3 km for each solar mass.”


Stephen Hawking, very famous for his ideas about black holes seeming to emit radiation (dubbed ‘Hawking radiation’) and also well known for his ability to function as a theoretical astrophysicist in the face of tremendous personal disability, has made some recent statements in a new paper that seem to challenge the nature of black holes’ event horizons (see Section 14.3, p. 363).

Credit and copyright: Alain Riazuelo

Marek Demianski, a cosmologist at Warsaw University and often a visiting professor at Williams College, evaluated the controversy as follows (February 5, 2014):”Yes, I read this short paper of Hawking. It is really nothing new; when one takes into account quantum effects a black hole is not black any more. Unfortunately we do not have yet a quantum theory of gravity so all these considerations are only hypothetical. From our practical point of view, quantum effects do not influence properties of astrophysical black holes.”

It looks like this theoretical debate is set to continue.

Links: accessible New Scientist article and overview of the Firewall Paradox; New Republic overview; Nature news article; Preprint of Stephen Hawking’s paper.