Scientists have again recorded the disturbance of space-time
The LIGO (Laser Interferometric Gravitational Observatory) collaboration reported: On December 26, 2015, gravitational waves swept across the Earth, to which the observatory's detectors responded. The event was the second recorded. The perturbation of the fabric of space-time was caused, as scientists believe, by the merger of two black holes, one of which is 8 times heavier than the Sun, and the other 14 times, into an object with a mass of 21 solar. This cataclysm of a universal scale happened 1.4 billion years ago, but the “ripples” from it, spreading at the speed of light, have come to us only now.
For the first time, gravitational waves were "caught" on September 14, 2015. What became a sensation. Those - "the first" also spread from the merger of black holes, but a greater mass - in 29 and 36 solar. The object, formed 1.3 billion years ago, became 62 times heavier than the Sun.
Obviously, repeated observation reinforces success. And there is no longer any doubt that gravitational waves really exist. What excites the imagination of astronomers.
Tunnels of laser interferometers of the gravitational observatory.
DETAILS
Promotional video:
The wave runs to the catcher and the beast
According to the General Theory of Relativity, which Albert Einstein announced in 1916, gravitational waves simply have to exist in the form of a kind of ripple in the fabric of space-time. They should be especially intensively propagated by cataclysms that constantly occur in the Universe - for example, supernova explosions, black holes forming and merging. Scientists believed that the resulting gravitational waves, spreading like circles on water, will sooner or later reach the Earth. Where and can be captured using instruments - gravitational observatories. The LIGO (Laser Interferometer Gravitational-Wave Observatory) is one of the largest in the world. Consists of two research facilities. One is in Livingston, Louisiana (Livingston, Louisiana), and the other is more than 3000 km away, in Hanford,Washington State (Hanford, Washington). Fishing on them lasted from 2002 to 2010. But to no avail. As if there were no gravitational waves in nature at all. And Einstein, therefore, was mistaken.
Einstein can be trusted even if one wants to doubt.
The essence of fishing is simple. Two laser beams are directed perpendicular to each other through long pipes. In LIGO, each pipe is 4 kilometers long. Then, with the help of mirrors, the rays are reduced into one. And they look at the result - at the interference pattern. If a gravitational wave arrives, then it compresses space in one direction and stretches in the perpendicular. The distances covered by the beams vary. And this can be seen in the picture, which is a concentric circle.
But before, nothing of the kind was visible.
The observatory has recently been modernized and named Advanced LIGO. Fishing devices, so-called laser interferometers, have become more sensitive. And it gave the result. It was announced on February 11, 2016 at a special press conference at the National Press Club in Washington.
Among the authors of this and the current discovery - researchers united in the international collaboration LIGO, there are also Russian scientists. They were collected by RAS Corresponding Member Vladimir Braginsky, professor at the Physics Department of Moscow State University and the California Institute of Technology. Today the team is headed by Valery Mitrofanov.
According to rumors, scientists managed to record as many as three gravitational waves, the sources of which are located in the constellations Dorado, Aries and Hydra. Two have already been announced. A message about the third wave will probably appear soon. It takes time to verify the observation results.
Merging black holes is still the main source of gravitational waves
SPECIALIST COMMENT
New window to the universe
It seems that Russian scientists were engaged in the most important thing - increasing the sensitivity of the instruments of the observatory.
“We changed the shape of the antennas to minimize extraneous noise,” says one of the authors of the discovery, scientific director of the Russian Quantum Center, professor at Moscow State University Mikhail Gorodetsky. - We also selected the optimal material for the mirrors - fused quartz. Colleagues suggested crystal sapphire, which turned out to be more "noisy" for testing.
The observatory's sensitivity eventually became phenomenal.
- For four kilometers, the recorded deviation is only 10 to minus 19 degrees of a meter - this is 10,000 times less than the diameter of a proton - the nucleus of a hydrogen atom, - said Gorodetsky.
According to the scientist, with the detection of gravitational waves, a new era began - gravitational wave astronomy. Another tool for exploring the Universe has appeared.
“We now have" ears "with which we can listen to the Universe, - says the scientist. - I'm not kidding: the frequencies of gravitational waves recorded by LIGO are actually sound - hundreds of hertz, kilohertz, they can be transformed into sound and listened to like birds chirping. We will record the most interesting events. Let's test the theory of relativity at a level of accuracy that is not available for other methods. Let's check new theories and, possibly, get closer to the creation of a quantum theory of gravity. Or even the grand unification theory.
- Now we have only two detectors, - explains Gorodetsky. “However, even with them, we can determine the masses of objects. And according to the delay time - the approximate position in the sky. For two antennas, the localization is not very good - some arc in the sky. But when the third European gravitational antenna in Italy is fully operational, we will be able to determine the position of the sources quite accurately using the triangulation method.
According to the scientist, this will make it possible to quickly aim at the area from which gravitational waves are emanating, optical and radio telescopes, to study their sources using traditional methods.
Astrophysicists complain that the VIRGO gravitational observatory in Italy has not yet connected to data collection. Then, with the help of detectors located at the corners of the giant triangle, it would be possible to accurately "track" the sources of gravitational waves. And Advanced LIGO only allows you to roughly indicate the direction to them.
Vladimir LAGOVSKY