Scientists have discovered gravitational waves. Why is it important

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11 February it became known that scientists were able to capture gravitational waves - a distortion of space-time, predicted by Albert Einstein. Their existence has been proven through observations using high-precision equipment - scientists recorded a signal to merge two massive black holes a billion light years from Earth.

Scientists are analyzing data coming from two Laser Interferometer Gravitational-Wave Observatory (LIGO) located in the states of Louisiana and Washington in the United States.

Based on the analysis of the data obtained by scientists from many countries, including Russia, it was found that the gravitational wave was caused by a collision of two black holes with a mass of 29 and 36 times the mass of the Sun. After that, they merged into one big black hole.

Russian expert Sergei Popov told us what gravitational waves are and why it is so important to measure them.

What are gravitational waves?

- Imagine yourself floating on the water, and waves are coming from it on the surface. That's about the same, and gravitational waves run through space-time. And when they pass through some piece where we live, they disturb the space-time around us. Perturb is very weak, because gravity is very weak compared to other forces. Measure it is difficult, but possible. And people over the past 50 years have tried to do this. And finally, it happened.

The fact that it was possible to fix the waves right now is due to the appearance of suitable equipment?

- Yes, first of all, it is equipment. The LIGO detector, the VIRGO detector, which will soon start working in Europe, is an absolutely amazing machine for measuring accuracy. Before that, people used cheaper, simpler approaches. LIGO is 25 years of work, huge sums of money spent, first of all, on research, on the creation of new technologies, on bringing these technologies to the mind and on the manufacture of these amazingly accurate instruments.

Black holes are associated with this story only because these are massive bodies that distort space.?

- In order to get a strong signal, you need not just a massive body, but both a massive and compact one. In essence, what happens is that one black hole falls on another. At this moment, heavy bodies interact with each other and move almost at the speed of light, and a lot of energy is emitted immediately, in a very short time interval. Therefore, LIGO and VIRGO specifically created for fixing signals from neutron stars and black holes. There are more neutron stars, and they merge more often, but black holes are more massive - they can be seen from a great distance.

How many had to watch black holes to detect a merging pair?

- In this case, LIGO was just lucky. Almost as soon as they turned on, they immediately saw a signal - the merging of two very massive black holes. The signal is very mass dependent. Normally, on average, black holes are three or even four times lighter, but in this case we were able to see the signal from a very long distance.

As the signal passes through space-time, does it weaken? If the phenomenon occurred in a billion light-years from Earth, then it must reach us in a subtle form?

- Naturally, and therefore it is also important that we managed to find two very heavy black holes. Normally, the detectors will see signals from the merger of two neutron stars, which are five or ten times closer to us.

Last question: why is the signal fixed in the form of sound?

- There are two points. First of all, people love pictures and sounds. Therefore, many signals — vibrations of stars or some other ones — are converted into sound form. But here, by the will of fate, the signal actually arrives at a frequency approximately equal to the frequency of our speech. Physically, these phenomena are different, but the frequencies are the same - kilohertz. Therefore, scientists have decided that this is such a beautiful move. The drawn graph, adopted during the experiment, talks about the form of the gravitational-wave signal, how the wave oscillates the mirrors in the measuring device. But usually people want not just to see a squiggle, but to get some kind of multimedia content.

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