In particle physics, it is called four basic interactions: gravity and strength, weak force and electromagnetic force. Gravity is the weakest one. The attraction between two protons is only110 of the electromagnetic force between them, and protons are only110 of the electromagnetic force in the weak electric field.
1679, Newton, a famous scientist, put forward the law of universal gravitation, arguing that there is gravitation between celestial bodies because of their mass, and found that the gravitational properties on all objects are the same.
Extended data:
Scientists in China measure the speed of gravity propagation.
After 10 years of continuous exploration, Chinese scientists have successfully obtained the observation evidence that "the gravitational field propagates at the speed of light" for the first time in the world. This original innovation has realized the expectation of physics to obtain the propagation speed of gravitational field through experiments or observations for many years, which is of great significance to the theoretical and experimental research of gravitational field.
On the afternoon of 26th, the Institute of Geology and Geophysics of China Academy of Sciences announced in Beijing that a scientific team composed of researchers from China Seismological Bureau and the University of Chinese Academy of Sciences, led by researcher Tang of the Institute, was established.
After 10 years of continuous exploration and observation of the earth's solid tide during multiple eclipses, it is found that the current formula of the earth's solid tide actually implies the assumption that the gravitational field propagates at the speed of light, and a method for measuring the gravitational propagation speed by using the solid tide is put forward.
Tang Keyun's scientific group observed the total solar eclipse in Mohe 1997, Zambia 200 1, Australia 2002, Jiayuguan 2008, Shanghai-Hangzhou Lake 2009 and Dali 20 10, Yunnan, mainly observing the gravity solid tide.
Chinese scientists have found that the theoretical formula of the current solid tide implies the assumption that the gravitational field propagates at the speed of light, and then the equation of gravitational propagation velocity is derived, and an effective method to solve the gravitational field velocity is found.
Tang Keyun's scientific group then selected the solid tide data of Shiquanhe Station in Tibet and Wushi Station in Xinjiang, which are far away from the Pacific Ocean, Atlantic Ocean, Indian Ocean and Arctic Ocean, and substituted them into the gravity propagation velocity equation, and finally obtained the first observation evidence of the global "gravity field propagating at the speed of light".
References:
Baidu Encyclopedia-Gravity (Law of Natural Science)