We recently commemorated a 100 years of Einstein’s Relativity Theory and now scientists have made a breakthrough in the most critical part of the theory – gravitational waves. After a century of testing, innovating and researching what Einstein had imagined, scientists finally have a proof of the presence of gravitational waves. LIGO, which stands for the Laser Interferometer Gravitational-Wave Observatory was created to detect gravitational waves.
The executive director of LIGO, David Reitze made the announcement on Thursday at the National Press Club, Washington. In his announcement, he mentioned that they had heard and recorded the sound of two black holes which had collided a billion years ago.
The mass of one black hole is equivalent to 29 suns while the other black hole has the mass of 36 suns. According to the team of scientists, each black hole was approximately 50 kilometers in diameter.
LIGO estimates that the two black holes had collided more than a billion years ago – approximately 1.3 billion years. They had merged at half the speed of light. The fact that gravitational waves pass through anything, made it possible for the waves to travel through the universe to reach earth.
The waves are so small that only a detector like LIGO which has the ability of measuring distortions which are one-thousandth the size of a proton can detect them. These gravitational waves were observed on September 14, 2015.
The scientists identified the sound of the collision of the black holes as a chirp which lasted for one-fifth of a second. Dierdre Shoemaker, who is a Georgia Tech Physicist who works on LIGO, said that gravitational waves are not sound waves but when the black holes were just kilometers apart, there was an increase in frequency which the LIGO team were able to observe.
LIGO is made up of two instruments which work in unison. One of them is located in Livingston, Louisiana while the other one is at Hanford, Washington. Its antennas are L-shaped and it has perpendicular arms which are 2.5 miles long. Each arm has a vacuum chamber which is cocooned in layers of steel and concrete. These vacuum chambers contain 2.5 gallons on empty space. The ends of each arm have mirrors hanging by glass threads.
These instruments detected tiny vibrations which came from the gravitational waves as they moved through the Earth. The LIGO team converted these wave signals into audio signals which allowed them to listen to the sound of the merging of the two black holes.
Ironically, Einstein who had made humanity aware of gravitational waves, had thought that they are so tiny that we will never be able to detect it. Now that we have proof of his theory, gravitational waves can play a pivotal role in understanding the universe. We can gain a better insight into objects in the universe like black holes and neutron stars.
Gravitational waves are so radically different from electromagnetic waves. This means that scientists will be able to delve deeper when it comes to understanding the universe. So far, we had relied on the electromagnetic waves to know about the universe. Because these waves encounter interference, our studies were limited. However, gravitational waves can travel through anything which means there is a lot more information which they can carry. One of the most enigmatic objects in the universe are black holes which do not emit light or radio waves. They can now be studied in a better way via gravitational waves.
Einstein had proposed the existence of gravitational waves in 1916. It was a part of his general theory of relativity according to which gravity was a distortion of space as well as time triggered by the presence of matter. Since then, scientists were only able to find indirect evidence of the existence of gravitational waves. When the LIGO team finally detected it, it took them 6 months to validate it before they could go public about it.
The detection of gravitational waves has started creating ripples in the world of science. Scientists and researchers will now be study celestial objects in a better way. The ripples in the fabric of space time which was proposed by Einstein years ago finally gets a stronger validation.