Stephen Hawking

21 Jan 2011

At www.physorg.com/news/2011-01-students-flock-legendary-physicist-stephen.html there is a story of students flocking to hear Stephen Hawking speak at Caltech in California. He can still draw a large crowd. His speciality is quantum gravity. In 1974 he predicted that black holes should thermally create and emit subatomic particles known as Bekenstein-Hawking radiation - until they exhaust their energy and dissipate. At www.dailygalaxy.com January 19th, 'Artificial white hole boosts Stephen Hawking's Black Hole theory' we have a story about an experiment by University of British Columbia physicists and engineers that helps bolster the Hawking theory. He said black holes are not really black - they glow like a hot body, and the smaller they are the more they glow. The temperature of a black hole varies inversely to its mass. According to the theory pairs of photons are torn apart by a black hole's gravitational field - one photon falling into the black hole and the other escaping as a form of radiation. A paper on the experiment was published by Physical Review Letters and while they don't prove Hawking's theory they show his ideas have traction.

Meanwhile, at www.physorg.com/print214635983.html we learn that researchers at Queen Mary University in London say they have found a way to determine the evolutionary stage of a black hole by analysing the region outside where matter cannot escape, the event horizon. It is basically mathematical science - a method based on the Kerr solution, a time-independent solution to the equations of General Relativity (paper published in The Proceedings of the Royal Society A - see http://arxiv.org/obs/1010.2421 ).