Gravitational Reverberations from NYT
Dennis Overbye, writing in the NYT, has a nice article on the significance of the BICEP2 measurements. He makes a point that I had not understood (I'm assuming that he is right). The gravitons themselves, theory says, are produced by the same process by which black holes leak. It is known as Hawking radiation, after Stephen Hawking of Cambridge University, the renowned black hole theorist, best-selling author and avatar of cosmic mystery who discovered it in a prodigious calculation in 1973. Shortly thereafter, William Unruh, now at the University of British Columbia, showed that you didn’t need black holes to see this radiation, just acceleration in space. In this case, the role of the black hole you can’t get out of is played by the rapidly retreating horizon you can’t reach in the inflating universe. Hawking radiation has been part of the physics firmament for decades; it’s the best-known prediction of quantum gravity. “Now it seems that Hawking and Unruh were right!” sai...