gravitational wave

Article

August 15, 2022

For the concept related to fluid mechanics, see gravity waves. In physics, a gravitational wave is a disturbance of space-time produced by an accelerated massive body. The existence of this type of wave, which consists of the propagation of a gravitational disturbance in space-time and that is transmitted at the speed of light, was predicted by Einstein in his theory of general relativity.[1]​[ 2]​ The first direct observation of gravitational waves was achieved on September 14, 2015; the authors of the detection were the scientists of the LIGO experiment[note 1] and Virgo who, after a thorough analysis of the results, announced the discovery to the public on February 11, 2016, one hundred years after Einstein predicted the existence of waves.[4] The detection of gravitational waves constitutes an important new validation of the theory of general relativity. Prior to their discovery, only indirect evidence for them was known, such as orbital period decay observed in a binary pulsar.[5] In March 2014, the BICEP2 experiment announced the detection of B-modes in the cosmic background polarization of microwaves, suggesting indirect evidence for primordial gravitational waves.[6] Combined studies with the PLANCK telescope revealed that the BICEPS2 results could be explained by interference from cosmic dust and were therefore shelved for lack of further evidence. evidence.[7] Gravitational waves are fluctuations generated in the curvature of space-time that propagate as waves at the speed of light. Gravitational radiation is generated when these waves are emitted by certain objects or by systems of objects that gravitate towards each other.

Theoretical background

General relativity is one of the theories of gravity that is compatible with special relativity in many respects, and in particular with the principle that nothing travels faster than light. This means that changes in the gravitational field cannot happen everywhere instantaneously: they must propagate. In general relativity they propagate at exactly the same speed as electromagnetic waves through a vacuum: at the speed of light. These propagating changes are called gravitational waves. Gravitational radiation is a central prediction of general relativity and its detection is a key test of the integrity of the theoretical structure of Einstein's work. However, in the long term it is likely to be even more important as an instrument for astronomical observation. Observations of the Hulse-Taylor binary pulsar system have provided excellent evidence that general relativity's predictions of gravitational radiation are quantitatively correct. Even so, information from astronomy about the possible sources of detectable radiation is incomplete. Every time a new band of electromagnetic waves was opened to astronomical observation with new observatories at that wavelength, the discovery of totally unexpected phenomena took place and it seems likely that this will happen again with the deployment of gravitational wave observatories, in especially because those waves carry some kinds of information that electromagnetic radiation cannot transmit. Gravitational waves are generated by the apparent motions of masses, which encode mass distributions and velocities. They are coherent and their low frequencies reflect the dynamic times of their sources. In a publication it is reported that, according to experts, the waves whose capture was announced on February 11, 2016 come from the collision of two black holes, one twenty-nine times larger than the Sun and the other with a size thirty-two. six times greater, which created a new