Friday, May 06, 2011

Frame Dragging and 'Gravity Probe B'

My article on the just-announced results from 'Gravity Probe B' has been published.

"A rotating black hole can generate huge amounts of energy for a sufficiently high-tech civilization. Outside the spherical event horizon lies an ellipsoidal region called the ergosphere – within this region spacetime is being dragged around the spinning black hole faster than light. In 1969 Roger Penrose showed that an object projected into the ergosphere can be made to escape with vastly increased energy while slightly slowing the black hole’s spin.

The dragging of space-time around a rotating mass is called frame-dragging (think honey around a twirled spoon) and is predicted by General Relativity. But is it real? A seven year NASA experiment called ‘Gravity Probe B’ has just reported in and it seems that, as usual, Einstein was right.
" ...

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