GRAVITATIONAL WAVES

Gravitational waves are invisible but very fast ripples in the universe space that expand and contract the space time around them. They travel at the speed of light (186000 miles per second).

CAUSES OF GRAVITATIONAL WAVES
The most powerful gravitational waves are created when objects move at very high speeds. Some examples of events that could cause a gravitational wave are:

when a star explodes asymmetrically (called a supernova)
when two big stars orbit each other
when two black holes orbit each other and merge

For explaining this let us consider a trampoline on which if we place weight, it will bend space around it. Greater the mass greater will be the bend. In this principle earth moves around the sun. If we consider sun of greater mass in space which bend space around it and if any object likes earth enter into this bend it will start moving around the sun. There is no such force which binds earth with sun, it is just a bending of space.

In this way if two bodies of greater mass orbit each other causing continuous distortion in space and as result produce ripples or gravitational waves. Not only two bigger bodies, but if two men dancing around each other in fabric space will also produce ripples. But these are very small that practically cannot be detected.

DETECTION OF GRAVITATIONAL WAVES
In 2015, scientists detected gravitational waves for the very first time. They used a very sensitive instrument called LIGO (Laser Interferometer Gravitational-Wave Observatory). These first gravitational waves happened when two black holes crashed into one another. The collision happened 1.3 billion years ago.

LASER INTERFEROMETER GRAVITATIONAL WAVE OBSERVATORY

When a gravitational wave passes by Earth, it squeezes and stretches space. LIGO can detect this squeezing and stretching. Each LIGO observatory has two “arms” that are each more than 2 miles (4 kilometers) long. A passing gravitational wave causes the length of the arms to change slightly. The observatory uses lasers, mirrors, and extremely sensitive instruments to detect these tiny changes.

EINSTEIN ABOUT GRAVITATIONAL WAVES

More than 100 years ago, a great scientist named Albert Einstein came up with many ideas about gravityand space.

Einstein predicted that something special happens when two bodies—such as planets or stars—orbit each other. He believed that this kind of movement could cause ripples in space. These ripples would spread out like the ripples in a pond when a stone is tossed in. Scientists call these ripples of space gravitational waves.

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