Theory of relativity

Theory of Relativity

The theory of relativity usually includes two mutually related principles by Albert Einstein: special relativity and general relativity. Apart from gravity, special relativity is applied to primary particles and their interactions, describing all their physical phenomena. General relativity explains the law of gravity and its relation with other forces of nature. It applies to astronomical and astronomical regions, including astronomy.

This theory transformed theoretical physics and astronomy during the 20th century, which was primarily a reversal of the 200-year-old mechanics theory created by Isaac Newton. It introduced concepts including space-time as an integrated unit of space and time, relativity of contemporary, kinetic and gravitational time span, and length contraction. In the field of physics, relativity improved the science of elementary particles and their basic interactions as well as beginning in the nuclear age. With the theory of relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes and gravitational waves.

Special Relativity 

Special relativity is a theory of space-time structure. It was introduced in Einstein's 1905 paper "On the Electrodynamics of Moving Bodies" (see the history of special relativity for the contributions of many other physicists). Special relativity is based on two terms, which are contradictory in classical mechanics:

1. The laws of physics are similar to all observers of the same speed relative to the same speed (principle of relativity).
2. The speed of light in the vacuum is similar to all supervisors, regardless of their relative speed or the speed of the light source.

The resultant principle is better than using classical mechanics. For example, Postulate 2 Michelson-Morley explains the results of the experiment. Apart from this, there are many surprising and responsive results of the theory. Some of these are:

• The relativity of simultaneity: Two incidents, together for a supervisor, cannot be simultaneously for another supervisor if the supervisors are in relative speed.
• Time dilation: Moving clocks are measured to last more slowly than a supervisor's "stable" clock.
• Length contraction: Objects are measured to minimize in the direction they are moving in relation to the supervisor.
• Maximum speed is finite: a physical object, message or area line can not travel faster than the speed of light in a vacuum.
• The effects of gravity can travel in space only at the speed of light, not fast or instant.
• Mass–energy equivalence: E = mc^2, energy and mass are even and permeable.
• Relativistic mass, the idea used by some researchers.

The defining feature of special relativity is the replacement of Galilean changes of classical mechanics by Lorentz changes.

General  Relativity 

General relativity is a theory of gravitation developed by Einstein in the years 1907-1915. The development of general relativity began with equilibrium theory, under which the speed of motion and physical rest in a gravitational field (for example, when standing on the earth's surface) are physically similar. Its decomposition is that free fall is inertial motion: an object is falling in the free fall because in such a way things move when there is no force on them, instead of due to gravitational force, as is the classical mechanics. It is incompatible with classical mechanics and special relativity because, in those theories, inertia moving objects cannot accelerate in relation to each other, but the object is freely doing so. To solve this difficulty, Einstein first proposed that the space-time is curved. In 1915, he prepared the Einstein field equations that are related to the curvature of space-time with mass, energy, and any motion within it.

Some of the results of general relativity are:

• Watches run slowly in deep gravitational wells. This is called gravitational time dilation.
• In Newton's theory of gravity, classes are unexpectedly in a sense. (It has been observed in Mercury's class and in Binary Pulsar).
• The rays of light bend in the presence of a gravitational field.
• "Drag" the spinning mass with the spacetime around it; An event is called "frame-dragging".
• The universe is expanding, and its distant parts are moving away from us faster than the speed of light.

Technically, general relativity is a theory of gravitation,  whose defining characteristic is the use of Einstein field equations. The solutions of field equations are metric tensors that define the topology of spacetime and move the object inertia.