Light beam in a gravitational field bends. The trajectory of a photon (particle of light) in a stationary gravitational field in the general case is not a straight line (spatial geodesic).
Light is electromagnetic waves certain hour. The equations of electrodynamics were formulated for inertial frames of reference, and in an inertial frame in vacuum, light rays will be straight. Newton's theory of gravity does not provide for any connection between the phenomena of electromagnetism and gravity, and therefore the prediction of Einstein's theory bending of light rays the gravitational field of the Sun was revolutionary and aroused great interest among physicists.
Bending of light rays by gravitational field can be understood without calculations, using a thought experiment proposed by Einstein. Let the elevator be held in the shaft by an electromagnet. There are holes on the opposite walls of the elevator at the same level, and opposite one of the holes on the wall of the shaft there is a light source. As soon as the light source turns on, the electromagnet turns off and the elevator begins to fall freely. The moment the light turns on, the elevator becomes inertial system reference point in which light propagates in a straight line. Therefore, a light ray entering the first hole will exit through the second. But during the distance the light travels L to the second wall of the elevator, equal L/c, the elevator will descend to a height h =gL 2 / 2c 2 and the beam will come out of the second hole into the shaft below the point at which it was emitted. In the reference system associated with the shaft, the beam will be curved.
The discovery of the bending of light rays by a gravitational field was the first experimental verification (except for the explanation of the precession of the orbit of Mercury) new theory gravity. Material from the site
During a total solar eclipse, the stars become visible. If you photograph the starry sky in the vicinity of the Sun and compare the resulting photograph with a photograph of the same section of the starry sky taken at a different time, then, in the presence of bending of light rays, the position of the stars in the photographs will be different . Within the limits of inevitable errors, the conclusions of the new theory of gravity were confirmed.
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change of direction light beam
Alternative descriptionsIn astronomy, this is the apparent deviation of stars from their true position in the sky
In biology, a deviation from the normal structure of an organism, often expressed only in a different size or color
Change in the apparent position of the star caused by the finite value of the speed of light and the movement of the observer along with the Earth
Distortion, defect, degrades the image in optical instruments
Deviation from the norm
Deflection of light rays under the influence of the speed of the Earth's movement
Distortion in optical systems
Image distortion in optical systems
Apparent deviation of the luminary from its true position
Deviation from something, as well as distortion of something
Apparent displacement heavenly bodies, caused by the rotation of the Earth around the Sun and its rotation around its axis
Distortion caused by optical instruments
Misconception
J. lat. physical friability and scattering broken rays Sveta; astronomer. a visible change in the position of the luminary, from wasting time on reaching us with a ray of light and from the earth running around the sun; break, slope
In contrast to Newton's theory, the curvature of the trajectory of a body moving in a gravitational field occurs not due to the action of a force, but due to the special properties of space. Coasting according to general theory relativity occurs in curved space-time.
Since all bodies, including light rays, move in the absence of forces along curved trajectories, we can assume that space itself is curved.
The physical properties of space near gravitating masses differ from the properties of space far from them. “The structure of general relativity is such that the equations gravitational field... are compatible only with such mass motion ... which satisfies the equations of conservation of energy and momentum" (Ya. B. Zeldovich, I. D. Novikov General theory of relativity and astrophysics). This means that if in the classical theory the field equations existed separately from the equations of motion, then in the general theory of relativity the gravitational field equations contain the equations of motion.
In his theory, Einstein completely abandoned the concept of gravity, replacing its effect with the curvature of world lines, the curvature of space-time itself. But the mathematical apparatus of the general theory of relativity turned out to be extremely complex, and the corrections to Newton’s theory of gravitation, obtained as a result of backbreaking computational work, are completely insignificant. Planck once said to Einstein about this: “Everything was explained so well, why did you do it again?”
There are not many control experiments in which the predictions of Einstein's theory can be discerned. An experimental test of the general theory of relativity was proposed by its author. Einstein pointed out three effects: the deflection of a ray of light when passing near a massive body, the rotation of the perihelions of planets, and the gravitational shift in the frequency of electromagnetic radiation.
When a ray of light passes through a gravitational field, its path must bend (based on the equivalence principle). Newton already posed this question: “Do not bodies act on light at a distance and do not by this action bend its rays?” Here Newton has in mind the repulsion of light from bodies, which does not depend on their mass, which explains diffraction.
The most sensational of all tests of the general theory of relativity was carried out in 1919 during total eclipse of the Sun by the English astronomer A. Eddington. According to general relativity, gravity bends light rays. This curvature is so minute that it cannot be detected by any laboratory experiment, but it can be measured by astronomers during a total eclipse of the Sun. Sunlight is blocked by the Moon and stars located near the edge of the Sun become visible. The light from them passes through the strongest part of the Sun's gravitational field. The shift in the apparent positions of these stars should indicate that the Sun's gravity is bending the path of light.
Newton's physics also predicted the bending of light in a gravitational field, but Einstein's equations gave twice the deviation. The deflection of the light beam turned out to be close to Einstein's prediction, but the difficulties in making accurate measurements of the positions of the stars during the eclipse turned out to be much greater than Eddington had expected.
Eddington spoke at a joint meeting of the Royal Society and the Astronomical Society in London. The President of the Royal Society, J. J. Thomson, said in his opening speech: “This is the discovery not of a remote island, but of a whole continent of new scientific ideas. This greatest discovery since Newton" ( Philipp Frank. Einstein, his life and times. N.Y., 1947, p. 141.).
At a Royal Society conference in 1962, a group of scientists concluded that since the difficulties were so great, eclipse observers should no longer attempt such measurements.
Beam of light passing through a distance 
from the center of the Sun, deflects under the influence of gravity at an angle
(1)
Where 
respectively, the mass and radius of the Sun.
The maximum deviation should be observed for a ray passing at the edge of the solar disk, where 
Observations during the 1952 eclipse gave 