What are gravitational waves? Do they really exist?

Albert Einstein’s general theory of relativity predicts the existence of gravitational waves, which should be produced when massive bodies are violently disturbed. For example, when a massive star collapses and becomes a black hole after ejecting outer layers in a spectacular explosion it emits gravitational waves — ripples that distort the fabric of space. (See the illustration below.)

According to general theory of relativity , this fabric is like a ‘rubber sheet’ in which all objects in the cosmos are embedded. A wave passing through it travels at the speed of light and this is what is called propagation of gravitation. Just as photons are carriers of electro-magnetism, the particles called gravitons are packets of gravity radiation and they can not surpass the speed of light — the ultimate cosmic speed limit. Thus, if the Sun were to vanish suddenly, the Earth would be liberated from its pull only after 8 minutes, the time taken by gravity waves carrying ‘information’ that the Sun is no longer there. As yet, however, there is no experimental evidence of gravitational waves. Nevertheless, the absence of evidence is not evidence of absence.

Additional reading:
Gravitational wave (Wikipedia)

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