what is gravity and what does it have on matter?
 Gravity, or gravitation, is a natural phenomenon by which all things with mass are brought toward one another, including objects ranging from atoms and photons, to planets and stars. The gravitational attraction of the original gaseous matter present in the Universe caused it to begin coalescing, forming stars – and for the stars to group together into galaxies – so gravity is responsible for many of the large scale structures in the Universe. 