Gravitational waves

In 1916, Albert Einstein expressed that gravitational fields should have their own gravitational waves. The discovery of gravitational waves can have no less fundamental significance than the discovery of radio waves. Perhaps a new kind of connection will appear. Some scientists believe that waves of gravity propagate hundreds of times faster than waves of an electromagnetic field.

In 1916, Albert Einstein expressed that gravitational fields should have their own gravitational waves

Gravitational waves should arise with every oscillation of gravitational masses. Their energy increases with increasing mass of the moving body and frequency of oscillation. Elementary particles, for example, fluctuate extremely quickly, but their mass is very small! The masses of planets, double and triple stars are colossal. But the frequencies of their oscillations are very small. In both cases gravitational waves have too low energy. But scientists, nevertheless, set the task of creating generators and receivers of gravitational waves.

An interesting idea for the experiment as early as 1969 was expressed by the American physicist Joseph Weber. Generator and receiver, he proposed to make of piezocrystals. If the piezoelectric crystal vibrates with a high-frequency electromagnetic field, it will become a source of gravitational waves, which, reaching another piezoelectric crystal, will cause deformation and the appearance of electric charges on its faces. But it turned out that it is practically impossible to put experience. A piezoelectric crystal with a volume of 50 m3 emits waves with a power of only one ten-trillion erg per second. A receiver with the same crystal catches the power of at least one hundred millionth erg per second. Hence, the receiver simply does not hear the transmitter's signals.

But this did not stop Joseph Weber, and he set another experiment, taking into account that only very massive objects generate sufficiently powerful gravitational waves that arise when stars collapse - their unlimited super-dense compression under the influence of enormous gravity, the rotation of neutron stars - "white dwarfs", the convergence of neutron stars... Perhaps, any of these sources really function near our planet system?

Here to register such, coming from the universe, gravitational waves and built its detector Joseph Weber.

As an antenna for trapping gravitational waves, Weber applied... the globe. It was the most massive body at his disposal. According to the scientist, the globe, having got into gravitational waves, should start to pulsate.

To record the gravity waves caused by the oscillations of the antenna-earth, Weber suspended thousands of kilogram aluminum cylinders in a vacuum chamber, isolated from extraneous vibrations. Gravitational vibrations of the Earth cause in it resonant elastic vibrations, registered by quartz strain gauges.

But this device should react to seismic and other local disturbances, which should be excluded. For this, Weber applied a system of filters and absorbers. In addition, he installed several such cylinders, placing them at distances of up to 1000 km from each other. To go through this distance, elastic waves from natural earthquakes will spend quite a lot of time. And pulsations, caused by gravitational waves, will act on distant detectors simultaneously or almost simultaneously. Weber considered only those signals received by his detectors with a time difference of no more than 0,4 seconds.

But it may be that seismic disturbances from different causes will reach three detectors simultaneously. Weber estimated that the probability of accidental coincidences is possible only once in 70 million years.

The detectors worked for 81 days. And it was discovered during this time of 17 coincidences on two detectors and several coincidences on three and even four detectors. At the same time, the power of the adopted oscillations turned out to be not so elusive at all. It was about 1% of the power of sunlight. Hence, the Earth is in the region of powerful oscillations of gravitational waves.

Subsequent experiments and calculations by Professor Weber have shown that the sources of gravitational waves that cause oscillations of its detectors are in the same direction as the center of our Galaxy, the center of the Milky Way.

Scientists plan to transfer experiments on the study of gravitational waves to the Moon, there are practically no processes that are associated with volcanic eruptions, tsunamis and earthquakes on Earth. Therefore, you can get rid of the disturbing background. Having located one cylinder of Weber on the Moon, the second one on the Earth, it is easy to compare the results of the readings and determine the velocity of gravity waves and their direction is much more accurate.