What is a gravity wave?
Gravity waves are ripples out from a super- massive collision, for example between two black holes, could be detected in the space time fabric through the stretching and contracting of space and time
How are they generated?
They can be generated by any accelerating body. Even two humans circling around each other can generate GWs , but they will not be intense enough to be detected. The GWs detected at present were generated by coalesce of two massive black holes, one 35 times the mass of the and other 29 times of the mass of the sun, 1.3 billion years ago( reached at present on earth because these black holes were 1.3 light years away).
How are they detected?
They were detected by LIGO system (Light Interferometer Gravitational wave observatory) which consists of two identical 4 km long tubes. The observatories are located in Washington and Louisiana(3000km apart) and GWs were detected by both these observatories to minimize the error. The Indian PM has given a green signal to setup 2 such observatories in India at Rajasthan and Maharashtra. These will take 8 years to come up and the proposed budget is around Rs 1260 crore
Why is the discovery of Gravitational waves important?
Gravitational Waves give a new dimension to explore the mysteries of the space. Earlier whatever we know about the universe , we know it through the light waves and electromagnetic waves.But most of the part of universe is opaque to light and electromagnetic waves. Some parts of the universe do not emit light waves like dark matter and black holes but they do emit gravitational waves. Using electromagnetic waves we cannot see further back than 400,000 years after the big bang. But with the discovery of gravitational waves we will be literally able to see big bang. In a nutshell GWs will help us identify hitherto unexplored dimensions of the Universe.