The theory of Einstein was put to the test. Guess what happened

Einstein's theory of relativity, which he has developed over the years, makes breathtaking predictions: moving clocks are slower than fixed clocks and objects are measured faster as a result. They move quickly. When he added gravity to his thinking, he deduced that the clocks worked more slowly when they were in regions of high gravity. He also predicted that light emitted in a place where gravity is strong will blush as it moves to places where gravity is lower.

But that does not mean that contemporary scientists accept complacently his theory of relativity as an undisputed fact. They have now sought to answer a new question: Are Einstein's predictions valid in an environment with a gravitational field much more powerful than that found on Earth?

A new experience imposed – and the black holes, the burned carcasses of massive stars subjected to gravitational forces so strong that the light could not even escape – offered the ideal environment to re-test Einstein's theory of relativity.

In the center of almost every galaxy is a huge black hole. In our own Milky Way, we have a mass whose mass is about 4 million times greater than that of our sun. It is called Sagittarius A *, after its location in the constellation Sagittarius.

The black hole is not isolated but rather surrounded by stars that gravitate very closely and sometimes in very elliptical orbits. And that's the key to the new measure. A star named S2 passed close to Sagittarius A *, passing through a region of gravity about a million times higher than that found on Earth.

There is a central feature of general relativity called local positional invariance, or LPI, which states that any measurement performed on a free-falling object must be identical whether it is a strong gravitational field or not at all. . It sounds a bit complicated, but it's not really different to say that a paratrooper's wristwatch should have the same weight when parachuting as the same watch. an astronaut in a deep space, where there is no gravity. This watch should work the same way for a hypothetical paratrooper on Jupiter, whose gravity is much stronger than that of the Earth.

Essentially, if LPI is true, the measurements must then be totally blind, whether they occur in a gravity field or not. If a measure invalidates the IPV, it also invalidates Einstein's theory.

It is impossible to get a stopwatch near a distant star or a black hole. Scientists had to find a different way of comparison. Stars consist mainly of two atomic elements, hydrogen and helium. Each element emits a unique set of colors and each color has a different frequency. This was well measured in the gravitational environment of the Earth, and scientists wanted to know if the elements emitted the same colors in an intense gravitational field. If they did not do it, it would invalidate the LPI.

Thus, to perform the test, the scientists observed the light emitted by S2 as it plunged into the powerful gravitational field of Sagittarius A *. Now, as the light emitted by the star has shifted from the high gravity near a black hole to the low gravity on Earth where scientists made their observations, it is expected that the colors appear more red on Earth than when they were released. by the star. However, the color of the light emitted by the hydrogen and the color of the light emitted by the helium should be reddened by the same amount.

And that's exactly what scientists have observed. Both elements emitted the same wavelengths of light when they passed through the powerful gravitational field of the black hole as they emitted into the Earth's weak gravitational field. Einstein's theory of general relativity was again validated and the results were published last month in Physical Review Letters.

Although this measure is clearly a scientific triumph, researchers are not resting on their laurels. A new facility, called the very large telescope, will be able to do even more accurate tests of general relativity, so we can be sure that more measurements are coming.

You may be wondering why scientists are constantly questioning well-established theories such as Einstein's, but that's just the nature of science. No scientific prediction is ever considered sacrosanct. Just as the gravity ideas developed by Sir Isaac Newton in the 1670s were replaced by those of Einstein, scientists expect Einstein's theories to be replaced by something better. . Until then, Einstein's theory of gravity will continue to reign supreme.