Einstein's general theory of relativity is an extremely important tool for representing the modern Universe, without which no satellite is launched. But how is it observed on a scale, for example, of an entire galaxy? Thanks to scientists, now we can say: it is perfectly observed. They conducted a study of two relatively distant galaxies located opposite each other, and proved that the theory of relativity is flawless.
The study used the Hubble Space Telescope and the Very Large Telescope to measure the mass of the galaxy in the foreground using both the gravitational lensing of its rear partner and the speed of rotation of the stars at its edges. The comparison made it possible to verify the measurements. As a result, the error was 9% - this is a lot, but today it is the most accurate measurement.
Not that the news is great, but general relativity is one of the strongest foundations of modern research. The detection of a weakness in general relativity will mean a revision of all modern physics, astrophysics and cosmology in favor of other, less proven and promising theories. Although this study does not prove that general relativity is the main principle of the universe, it saves scientists and companies from the need to discard the knowledge accumulated over decades.
In the next decade, two new telescopes - the Euclid satellite and the Large Synoptic Observation Telescope - will be able to find deviations from general relativity on scales 1000 times larger than the scale of this study. If general relativity passes these tests, we will be sure that this is the correct theory describing the effects of gravity in the universe as a whole. As long as she manages, Einstein would be proud.
Ilya Khel