What is dark matter?

Dark matter is an invisible substance that may exist in the universe. It may be the main component of cosmic matter, but it does not belong to any known matter that constitutes visible celestial bodies.

Modern astronomy shows that dark matter may exist in a large number of galaxies, star clusters and the universe, and its mass is far greater than the sum of all visible celestial bodies in the universe through the observation of celestial movement, Newton's gravitational phenomenon, gravitational lens effect, the formation of large-scale structure of the universe and microwave background radiation.

Combined with the anisotropic observation of cosmic microwave background radiation and the standard cosmological model (λλCDM model), it can be determined that dark matter accounts for 85% of the total mass of all substances and 26.8% of the total mass energy of the universe. It is generally believed that dark matter is composed of "weakly interacting massive particles" (WIMP).

Astronomer Kapteyn first proposed that "dark matter" might exist. 1922, he proposed that the invisible matter around the star can be inferred indirectly through the motion of the star system. 1932, astronomer Janot studied the motion of stars near the solar system in dark matter. However, it failed to draw a conclusion about the existence of dark matter. 1933, astrophysicist FritzZwicky used the spectral red shift to measure the speed of each galaxy in the constellation Ursa relative to the cluster.