What is general relativity?

General relativity is a scientific theory describing how matter, energy, time and space interact. He was first released by Albert Einstein in 1917 as an expansion of his theory of special relativity. General relativity considers space and time to be the only unified four -dimensional "space -time"; Within general relativity, the matter deforms the geometry of space -time and the deformation of space -time causes the movement of matter, which we consider to be gravity.

The basic prerequisite for general relativity is that the forces caused by gravity and forces caused by acceleration are equivalent. If the closed box passes through the acceleration, no experiment performed in the box can determine whether the box is at rest in the gravitational field or accelerates with the universe. This principle that all physical laws are the same for accelerated observers and observers in the gravitational field is called the principle of equivalence; It was experimentally tested for more than twelve decimal accuracy places.

The most important consequence of the ECV principleThe Ivenge is that the space cannot be Euclidean for all observers. In a curved area, such as a distorted sheet, normal geometry laws do not always hold. In the curved area it is possible to create a triangle, whose angles add up to more or less than 180 degrees, or to draw two parallel lines that intersect. Special relativity becomes increasingly accurate because the curvature of space -time goes to zero; If the space -time is flat, both theories become identical. How does the curve calculate using Einstein Field equations that have a form G = T; G describes the curvature of the space while t describes the distribution of matter.

Since the space is curved, objects generally do not always move in lines, just as the ball will not move in a straight line if you throw it into a funnel. The free -falling object will always take a snare way from point A to point B, which is not necessarily a straight line; The line it travels is known as geodesic. We see deviations from directThe line as the influence of "gravity"- the Earth does not move in a straight line, because the sun curriculum around the Earth, so it moves in the elliptical orbit.

Since gravitational forces and acceleration forces are fully equivalent, all effects on a fast -moving object in special relativity also apply to objects deep in gravitational areas. The object close to gravity emits Doppler's shifted light as if it accelerated. It also seems that objects close to gravitational sources will have time to slow down and any incoming light will be bent in the field. This may cause a strong source of gravity bending light as a lens, focusing remote objects; This phenomenon often occurs in deep astronomy, where one galaxy bends the other the other, so it will perform more.