LIGO - Super gravitational wave detector

The device called Advanced LIGO has helped scientists with more than 1,000 members discover and validate the existence of gravitational waves as predicted by Einstein 100 years ago.

According to Business Insider, LIGO stands for Laser Interferometer Gravitational-Wave Observatory, which means that the gravitational wave observation station is made of laser beams.

This $ 620 million system has helped astronomers observe the phenomenon of two black holes merging. This process generates gravitational waves - the space-time ripple like Einstein predicted in 1916. This wave will spread from the source at the speed of light in space and to Earth.

Advanced LIGO system principle detects gravitational waves.(Photo: Wikipedia).

However, spacetime compression and relaxation fluctuations caused by gravitational waves are too small, about one-millionth of the width of a hydrogen atom. That's why Einstein thinks that humans cannot discover them.

Thanks to Advanced LIGO , scientists have proved Einstein's prediction for the first time.

Advanced LIGO uses a very high-sensitivity laser system, capable of detecting distortions of a billionth of a meter, enough to capture gravitational waves. It consists of two detectors, one located in Livingston, Louisiana, and one in Hanford, Washington. In this way, the signals obtained from a detector can be confirmed or denied quite quickly by the second detector.

At each detector, engineers fired a powerful laser into a splitter to divide the laser beam into two, going in two different directions in two 4km long tunnels. After reflecting at the mirror at the end of each tunnel, two laser beams reunite as one.

If there is no turbulence caused by gravitational waves, the two reunited laser beams are calculated to cancel each other out, as both move in the same amount of time. If gravitational waves act on the path of one of the beams, a light flash will be obtained at the detector. This light is what LIGO has been waiting for 14 years.

On September 14, 2015, scientists obtained the same flashing signal in both machines.

From this signal, they calculated that this gravitational wave is due to the merger of two black holes , one with 36 times the mass of the Sun and one 29 times more. These two black holes revolve around each other in a spiral and 1.3 billion light-years away.

This signal was later turned into an audio signal by LIGO with increasing pitch, peaking at the time the two black holes merged.

LIGO system located in Livingston.(Photo: LIGO).

According to Szabolcs Marka, a physics professor at Columbia University, based on the sound obtained, it is possible to classify gravitational waves emitted by supernovae or black holes.

"They sound different," she said.

The mass of a new black hole is 62 times heavier than the Sun. Compared to the total volume of two component black holes (36 and 29), three solar masses are lost. According to the team, this mass has turned into gravitational wave propagation energy.

The Earth and the Sun also emit gravitational waves. According to calculations by theoretical physicist Luboš Motl, the energy of this gravitational wave is enough to light two Edison bulbs. The gravitational energy of these two black holes is 10 times greater than 44 times.

This is the first time in history that people "see" two black holes merged. Previously, astronomers did not dare to say whether or not such a collision could occur, because there was no way to detect it.

In the next five years, scientists will transform LIGO's sensitivity to 1,000 times, hoping to catch the signal of more gravitational waves in the near future.

Accompanying LIGO in the gravitational wave hunt is the modern Virgo interferometer located at the European Observatory in Italy and the Kamioka gravitational wave detector located in the Kamioka mine, Japan, scheduled to enter. operation in 2018.

"It's great to be a scientist," said Professor Marka.