Dark Matter: Astrophysical Evidence and Constraints

1. Introduction Modern physics and astronomy are now obscured by two "dark clouds," namely, dark matter and dark energy.All the stuff that we are familiar with in our everyday life,such as flowers, rocks, water and air, which are made of molecules or atoms, including electrons and photons,constitutes only 5% of the energy content of the universe.Even the standard model of elementary particles, the most successful ever, is only able to explain such a small