Hawking conference takes aim at paradox of black hole theory
By academia's standards, the list of participants packs as much star power as an Academy Awards ceremony. But the Hawking Radiation Conference, which begins Monday at KTH Royal Institute of Technology, has been convened to take on a slightly different matter of business.
Stephen Hawking and some three dozen of the world's most influential physicists will convene on KTH's campus to seek a solution to a puzzle that has vexed science for years: whether singularities actually exist in black holes, and whether Hawking Radiation has any bearing on their existence.
Unlike the Oscars, however, the weeklong event will take place behind closed doors, in Kollegiesalen in the administration building at KTH.
The Hawking Radiation Conference was called by Laura Mersini-Houghton, a theoretical physicist at the University of North Carolina (UNC).
"The purpose is to bring together the people who have studied Hawking since the 1970s, and put them in one room and try to solve this question," Mersini-Houghton says. "When I had the idea for this conference, I called Professor Hawking. He immediately said yes and he set the date."
The list of participants in the sessions, which run from August 24 to 29, reads like a who's who of modern physics history, including such prominent names as Leonard Parker, Gerard 't Hooft and Paul Davies.
Because Hawking is restricted from air travel due to medical reasons, Mersini-Houghton had to find a setting that he could reach without having to fly. The selection of KTH came about because Nordic Institute for Theoretical Physics (Nordita) offered to host the event in Stockholm. Nordita, which is co-hosted by KTH and Stockholm University, is co-sponsor of the conference, along with UNC and the Julian Schwinger Foundation.
Last year, Hawking took the science community by surprise, suggesting that " there are no black holes, in the sense of regimes from which light can't escape to infinity."
The classic picture of a black hole, is a region in spacetime that forms when a massive star exhausts its fuel and collapses under the force of its own gravity into what is called a gravitational singularity — a single point in which the mass of the original star is compressed. The singularity has been thought of as a point of infinite density, which is surrounded by a gravitational field so powerful that nothing, not even light, can escape. With the singularity at its core, the field forms a sort of bubble, known as the event horizon. This is the region beyond which any matter that enters is supposedly lost forever.
But this system presents a paradox, pitting Einstein’s theory of gravity, which predicts the formation of black holes in which physical information is lost forever, against a fundamental law of quantum theory, which states that no information about the physical state of anything in the universe can ever disappear.
Hawking's theory that black holes emit radiation and eventually evaporate established a link between quantum mechanics and general relativity. Observations have confirmed the prediction of "Hawking radiation", but as Hawking himself notes, observing a singularity itself is impossible.
A number of theories have been proposed to solve the information loss paradox, but widespread disagreement continues among physicists.
"I think this was the right time for this problem to be taken on by this group, absolutely," Mersini-Houghton says. "In all likelihood, we will never have so many of the founding members of modern physics in the same place again to try to solve one of the most fundamental questions related to black holes and the nature of spacetime.”
The conference kicks off at 10:45 a.m. August 24, with 15 minutes of public welcoming remarks, after which the doors will close for private discussions that will continue for five days. In the evening, Hawking will deliver a public lecture at Stockholm's Waterfront Congress Centre. The lecture is sold out.