Who ordered dark matter? The necessity of dark matter

Dark matter is a component of matter in the Universe, whose existence is apparent only via gravitational interactions, not via electromagnetic interactions. The amount of dark matter in the energy budget of the Universe is about five times larger than that of the baryonic component in the standard model, but its origin is still not understood. So in this article, we discuss various astrophysical phenomena, virial motion of stars, the flat rotation curve of galaxies, weak gravitational lensing and cosmic microwave background radiation, which clearly show the effects of dark matter and provide theoretical opportunities to explain it.