What are gravitational waves

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A recent research showed that gravitational waves exist,you all or maybe some of you have been wondering that what am i talking about. don’t worry I’ve got your back so lets start with a little definition

Gravitational waves are ripples in the curvature of spacetime that propagate as waves, generated in certain gravitational interactions and travelling outward from their source.
The possibility of gravitational waves was discussed in 1893 by Heaviside using the analogy between the inverse-square law in gravitation and electricity.In easy words you can say that the waves or ripples created in the fabric of space time due to a distant violent explosion,merging of blackholes or maybe something are called gravitational waves

When were they first predicted ?

Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity.2687961.main_image.jpg

What do gravitational waves do that allowed them to be detected?

Gravitational waves travel outward from their source at the speed of light (a prediction confirmed by the new discovery), slightly distorting space as they pass through it— with the key word being “slightly.” The changes predicted to occur as gravitational waves pass by are so small that Einstein himself doubted that we’d ever be able to detect them. But advances in science and technology proved Einstein too pessimistic in this case, since they have now been observed with the detectors known as LIGO, short for Laser Interferometer Gravitational-Wave Observatory.

Who discovered gravitational waves and how did one discovered them ?

Gravitational waves were discovered on 11 feb 2016,and they were discovered by LIGO(laser Interferometer Gravitational-waves observatory).There are two LIGO detectors, one in Louisiana and the other in Washington State. Each consists of an L-shaped pair of four-kilometer-long arms with mirrors at their ends. (Yes, you read correctly: four kilometers long! These are large scientific instruments.) In essence, LIGO measured very slight changes in the lengths of the arms as the gravitational waves passed through. However, the changes in length are smaller than the size of an atomic nucleus, so they cannot be measured with rulers. Instead, they are measured with what physicists call an interferometer (the ‘“I” in LIGO); the LIGO interferometers use lasers in a way that allows the detectors to notice when lengths change even by incredibly tiny amounts.

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(image courtesy:NASA)

Why is this discovery important to science?

The direct detection of gravitational waves once again validates Einstein’s general theory of relativity but, as above, we already had strong evidence that these waves existed. So the more important part of this discovery is that direct detection opens up an entirely new way of studying the universe, allowing us to “observe” events that are invisible to ordinary telescopes and that probe some of the most exotic objects in the universe, including black holes. (Note: Scientists also expect to be able to detect evidence of gravitational waves from the Big Bang, and you may recall that such a detection was announced in 2014, but then retracted once scientists realize they may have been seeing an artifact from cosmic dust rather than a signal from the early universe.


Detected again?

The two LIGO gravitational wave detectors in Hanford Washington and Livingston Louisiana have caught a second robust signal from two black holes in their final orbits and then their coalescence into a single black hole. This event, dubbed GW151226, was seen on December 26th at 03:38:53 (in Universal Coordinated Time, also known as Greenwich Mean Time), near the end of LIGO’s first observing period (“O1”), and was immediately nicknamed “the Boxing Day event”.

 

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