Published in Physics World, 15 Feb 2011
Light passing near to the spinning black holes thought to reside at the centre of many galaxies becomes twisted, possibly offering a new way to test Einstein’s general theory of relativity. That is the conclusion of an international team of physicists, who say the phenomenon could be seen with existing telescopes.
The general theory of relativity (GR), put forward by Einstein more than 90 years ago, predicts few phenomena that can be easily tested. One example is gravitational lensing – that the gravity of stars and black holes can warp space–time enough to bend the passage of light. Another is time dilation, which makes clocks sitting in regions of lower gravity – say, at high altitudes – tick faster. Scientists are still trying to directly detect yet another general-relativity phenomenon called gravitational waves. These are ripples in space–time thought to be generated when large masses accelerate. […]
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