1. Proposition of the theory of relativity
The theory of relativity is the basic theory about space-time and gravity. It was mainly founded by Einstein. It is divided into special relativity and general relativity according to different research objects.
The theory of relativity has greatly changed mankind's "common sense" concepts about the universe and nature, and proposed brand-new concepts such as "simultaneous relativity", "four-dimensional space-time" and "curved space-time".
Einstein's theory of relativity reveals the inseparability of time, space and material motion, and is the theoretical basis for the invention of nuclear weapons.
2. Verification of General Relativity – Black Hole
In 1916, German astronomer Karl Schwarzschild calculated a vacuum solution to Einstein's gravitational field equation. This solution showed that if a large amount of matter is concentrated at a point in space, there will be an interface – an "event horizon" – around the particle point. Once inside this interface, not even light can escape.
This celestial body was named a "black hole" by American physicist John Archibald Wheeler. Black holes cannot be directly observed, but their existence and mass can be known indirectly.
In 2016, the LIGO Scientific Collaboration and the Virgo Collaboration team announced that they used the advanced LIGO detector to detect the gravitational wave signal from the merger of dual black holes for the first time. The evidence that the merger of black holes produces gravitational waves is regarded as strong proof of Einstein's general theory of relativity.
In 2019, the first black hole photo was released, which once again tested the correctness of general relativity.
[Knowledge link] Black hole
At 21:00 on April 10, 2019, Beijing time, mankind’s first photo of a black hole was released. The black hole in the photo comes from the center of M87, a giant euphytic galaxy in the constellation Gemini. It is 55 million light-years away from the Earth and has a mass of about 6.5 billion times that of the sun.
This photo was taken by astronomers using 8 millimeter/submillimeter wave radio telescopes around the world to form a so-called "event horizon telescope".
In November 2019, the research team of the National Astronomical Observatory of the Chinese Academy of Sciences discovered the most massive stellar black hole to date relying on the Guo Shoujing Telescope (LAMOST). This black hole with a mass of 70 times that of the sun far exceeds the upper limit of mass predicted by theory, and is expected to promote new theories of slow star evolution and black hole formation.
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