In 2015, scientists made a groundbreaking discovery that proved Einstein's theory on disturbances in space-time. They detected gravitational waves for the very first time.
Back in 1916, Albert Einstein published his theory of general relativity, and predicted that objects with large mass accelerating in space would create ripples in the fabric of space and time. These ripples are caused by two black holes that enter each other's gravitational field. As they pull on each other, they get closer and closer and spin around each other at colossal speeds, until they finally collide to form a far bigger black hole. This phenomenon creates a violent disruption of gravitational waves.
Although the mathematics proved this to be possible, it was never detected before. This is where LIGO comes in.
LIGO stands for the Laser Interferometer Gravitational-wave Observatory, and is one of the most cutting edge science experiments ever to be performed. LIGO consists of 2 "arms" that stretch out 4km in length. Each arm carries an infrared laser that is emitted from the centre outwards at a 90-degree angle until it is reflected back from a mirror. The pulse from each returned beam of light is carefully analysed, and interruptions from this is what LIGO scientists are looking out for.
However, these fine interruptions may be caused by other natural phenomenon, such as earthquakes on the other side of the Earth. In order to factor out any other interruption besides gravitational waves, another LIGO apparatus was built in another State. This way, they could measure when each laser detected interference. If the time differed by a fraction of a second, it would not be a gravitational wave, but if the interruptions had no time difference whatsoever, it would be a gravitational wave strike.
LIGO plays a waiting game and is based on luck. Physicists, Rainer Weiss, Kip Thorne and Ronald Drever, working at LIGO, detected the first-ever gravitational wave on the 14th of September 2015.
Take a look at the video below by the YouTube channel, Physics Girl, on I Visited the First Gravitational Wave Detector! LIGO - Stellar...