Update: please see “Direct observation of gravitational waves by the Advanced LIGO” for the latest information.
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When binary neutron stars collapse into a black hole or when black holes collide gravitational waves emerge from the center of those collisions. Supernovas can create gravitational waves too. In general any massive object will create gravitational waves if it is accelerating.
Gravitational waves are implied by the equations of General Relativity (Einstein’s theory of gravitation). In the last 100 years many aspects of General Relativity have been verified by the astrophysical and astronomical observations but the gravitational waves have not been observed directly yet. There is indirect evidence for gravitational waves from the measurements of binary neutron stars.
Gravitational waves are distortions in space-time. The distortion travels like a wave. When it passes through an object it will cause very small temporary distortions in the shape of that object. When you experience a gravitational wave your shape oscillates.
In the image above the changes in shape are exaggerated. The real change will be tiny. So tiny in fact that you need a special instrument that can detect changes in size smaller than the size of a proton. Do we have such an instrument? Now we do! It has been in the works for the last 20 years. It is known as the Advanced LIGO which has now reached the sensitivity to detect the gravitational waves.
There are few resources on the web regarding Advanced LIGO but you should really start with the Quanta Magazine’s interview with Gabriela González.
In Europe there are similar experiments. Virgo in Italy an GEO600 in Germany.
Suresh Emre
Renaissance Universal 