The Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected and recorded the sound of two black holes colliding billions of light years from Earth. This marks the first direct evidence of gravitational waves, which are ripples propagating through the fabric of the universe.
Albert Einstein first predicted the existence of gravitational waves in 1916 as part of his theory of relativity, according to the California Institute of Technology. The scientist believed that massive objects such as black holes or neutron stars would accelerate or decelerate through space-time, radiating energy that would be carried away by gravitational waves.
Einstein proposed that these waves would carry information about their origins and even the nature of gravity as they travel at the speed of light throughout the universe.
Professor Stephen Hawking told the BBC in an interview that the undeniable evidence of gravitational waves would allow scientists to look at the Universe from a completely new perspective.
“The ability to detect them has the potential to revolutionize astronomy. This discovery is the first detection of a black hole binary system and the first observation of black holes merging”, said Hawking.
This discovery also reveals that two black holes are merging together, as U.S. News reported. They also are much larger than expected. Previous research on black holes are focused on the study of binary systems with black holes of a mass five to twenty times that of the sun, but the ones discovered by LIGO size up to about 30 times the mass of the sun.
The fact that stars can create such massive black holes will certainly mark the beginning of a new era in astronomy since it will lead scientists to study the universe through a completely new lens.
LIGO began focusing on gravitational waves in 2002 until it was shut down for not having recorded a single wave after eight years. The observatory was back in action last September when it armed itself with new technology under the Advanced LIGO brand.
It now consists of two interferometers, twin tubes that meet to form an L-shape. Right where the two tubes meet, an 180-watt laser beam is split in two and the resulting twin beams traveling down each tube hit a very precise mirror. Then, the beams meet again at a light sensor after bouncing back about 400 times.
The twin beams produce an interference pattern of dark and bright areas at the light sensor. Scientists analyze these areas, which are called fringes, and detect changes over time in the distance which light travels. Should a gravitational wave pass by, one tube of LIGO will be squeezed while the other is stretched.
The observatory has two facilities that have the exact same design. One is located in Hanford, Washington, and the other is in Livingston, Louisiana.
Source: Los Angeles Times