Simply Gravitational waves are ripples in the fabric of space-time caused by some violate and energetic processes in the Universe .When an object accelerates, it creates ripples in space-time, just like a boat causes ripples in a pond (and also similarly an accelerating electrical charge produces an electromagnetic wave). These space-time ripples are gravitational waves. They are extremely weak so are very difficult to detect.
The concept of Gravitational Wave was first predicted by Albert Einstein in 1916 In his Theory Of General Relativity .”General relativity states that mass distorts both space and time in the same way a heavy bowling ball will distort a trampoline.”
After 100 years of Einstein’s prediction,Gravitational Waves have been detected .This is one of the best and most important success in the field of science especially in Physics & Astronomy .
On February 11, 2016, the LIGO Scientific Collaboration and Virgo Collaboration teams announced that they had directly detected gravitational waves using the Advanced LIGO detectors from a pair of black holes merging.
How Are Gravitational Waves Formed ?
Einstein’s mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that ‘waves’ of distorted space would radiate from the source. Furthermore, these ripples would travel at the speed of light through the Universe, carrying with them information about their cataclysmic origins, as well as invaluable clues to the nature of gravity itself.
The strongest gravitational waves are produced by catastrophic events such as colliding black holes, the collapse of stellar cores (supernovae), coalescing neutron stars or white dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and the remnants of gravitational radiation created by the birth of the Universe itself.
Gravitational waves are important in telling us about the early universe. The cosmic microwave background gives us a snapshot of the universe about 380,000 years after the start of the universe. Looking very closely at the cosmic microwave background there are patterns seen which can also be measured in the large scale structure of the universe (so galaxies and clusters) today. These patterns in the cosmic microwave background were caused by very tiny random perturbations from the time when the universe expanded rapidly, known as inflation.