Gravitational Wave Astronomy

posted 5 Feb 2015, 01:00 by Philip Green
Chris Berry
At our February 2015 meeting, Dr Christopher Berry from the School of Physics of Birmingham University tried to explain gravity waves to our members - what they are; how they are produced; and how to detect them!
Although produced by any accelerating mass (ie bodies in orbit around another mass) as a direct prediction from Einstein's General Theory of Relativity, it needs objects to be as massive as binary neutron stars or binary black holes to generate gravity waves big enough that stand a chance of being detected. Even then, the changes/distortions caused by the gravity waves are infinitesimal - requiring detectors that would be able to measure the difference of something as far away as Alpha Centuri by the width of a human hair!!
And in 2015, various ground based detectors of this sensitivity, like 'Advanced LIGO' will be coming on-line. up to 4km long, perpendicular laser beams, sighted across the world, able to measure the tiny changes in the stretching of space/time caused by these gravitational waves! Amazing!!