Gravitational waves do exist, and astronomy will never be the same - CNET

How do you picture gravitational waves? Think of spacetime like a taut sheet. Rolling a ball across the sheet causes it to curve. As the ball moves, the sheet's curvature moves as well and certain objects moving quickly cause ripples across the sheet.

Einstein's original theory proposed that as mass changes position, it causes a ripple in the universe's gravitational field, a wave travelling at the speed of light outward from the source. Gravitational waves are caused by objects like oddly shaped spinning planets and binary black hole and star systems. Theories also suggest that supeovae, and even the Big Bang itself, are a source of gravitational waves. You can read more about them on Einstein Online.

Now that LIGO has detected these waves, researchers have an entirely new way of studying these objects and events. In the case of black holes, which are very difficult to study since we cannot view them directly, it could blow research wide open. Researchers may be even to peer back to just a split second after the Big Bang, something that is impossible with other methods.

Stop and think about that for a second. We may finally be able to see the beginning of time. The universe. Everything there is.

The LIGO facility uses two 4-kilometer (2.5-mile) long arms in an L shape as "antennas" to track gravitational waves. Each arm contains an interferometer, an array of lasers and mirrors used to detect the minute movements that gravitational waves would cause -- movements 10,000 times smaller than a proton.

But detecting gravitational waves is not easy to do. Gravity is, for something that binds the universe together, surprisingly weak. For almost a decade LIGO facilities failed to detect any gravitational waves. Five years of upgrades led to Advanced LIGO going live in September 2015 and it has identified XX waves in less than six months. The addition of a third facility will allow the team to triangulate the waves to find their source.

Robert Ward, an Australian National University scientist who installed the interferometers (the devices used to track waves), explains how Advanced LIGO works.

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