The discovery of gravitational waves and a new era of astronomy: comments of Russian physicists

February 11, 2016 will go down in history forever. On this day, one of the greatest scientific discoveries of recent times took place - the discovery of gravitational waves , predicted almost a hundred years ago by the general theory of relativity of Albert Einstein. A ripple in the fabric of space-time, which distorts the space and time around itself, reached the Earth and was first directly recorded.

“We are opening a new era - the era of gravitational-wave astronomy. This can be compared with the appearance of a telescope or radio astronomy. We have a new tool for studying the Universe, ” says Mikhail Gorodetsky, one of the LIGO project participants, the head of the Coherent Micro-optics and Radiophotonics group at the Russian Quantum Center (RCC).

The international project LIGO (Laser Interferometer Gravitational-Wave Observatory), a laser-interferometric gravitational-wave observatory, was launched in 1992, now scientists from 15 countries are participating in it. From the very beginning, Russian physicists participated in the experiments, including research groups under the guidance of Valery Mitrofanov, a professor at the Faculty of Physics of Moscow State University.

Today, Valery Mitrofanov and other prominent Russian physicists took part in a press conference at which they spoke in detail about the discovery. Below is a video of the press conference. Professor Mitrofanov speaks first, he first commented on a live broadcast from Washington. They officially announced the sensational news, rumors of which have been going on for several weeks.
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Then Valery Mitrofanov himself briefly explained the technical side of how the experiment went:

“The signal was caught from two black holes that are located about 1.3 billion light-years from us. Holes revolved around each other and eventually merged into one. About this gravitational waves are signaled by a surge, which detectors recorded. It is important to emphasize that this is a direct registration of the waves, and not an indirect one. For indirect in 1993 was awarded the Nobel Prize. The detectors caught the signal at 10 minus 19 degree meters. Today it is the ultimate measurement accuracy that has so far been achieved on Earth.

With regard to the contribution of Russian scientists, it is, above all, the creation of systems that allow you to select such a weak signal against the background of noise. The task, frankly, is the hardest. ”

Black holes had a mass of approximately 30 solar masses each and rotated around each other with a frequency of 150 Hz. After the merger, the mass turned out to be three solar masses less than the sum of the masses before the merger: the remaining energy was emitted in the form of gravitational waves.

Reaching the Earth, gravitational waves began to distort our space-time. Accordingly, the distance between the antenna elements of the LIGO Observatory periodically began to change, as detected by the laser beam detectors.

Gravitational waves were recorded on September 14, 2015 at 13:51 Moscow time.

“This is the ultimate achievement of human civilization,” said Sergey Vyatchanin, a professor at Moscow State University. - LIGO has almost reached the quantum limit of measurements. It was possible to register the displacement of two macroscopic objects with a mass of several kilograms and separated by several kilometers with an accuracy predicted by Heisenberg's quantum uncertainty. ”

“Now we have only two detectors, but even with them we will be able to determine the masses of objects, and by the delay time we can estimate their approximate position in the sky,” said one of the authors of the discovery, scientific director of the Russian Quantum Center, professor at Moscow State University Mikhail Gorodetsky. “For two antennas, localization is not very good — some arc in the sky, but when the third European gravity antenna is fully operational, we will be able to determine the position of the sources quite accurately using the triangulation method.”


L-shaped antenna and LIGO observatory in Louisiana

By the way, it was Russian physicists who suggested hanging mirrors on quartz filaments instead of steel (laser beams reflected from the mirrors in each four-kilometer arm of the L-shaped interferometer), which reduced the ambient noise in the system. Without this, the discovery would hardly have taken place.

Video of the press conference