According to astronomers, massive galaxies in the cosmos have stopped forming their own stars and are as an alternative cannibalizing their neighbouring galaxies. Here is an amazing computer simulation of our own Milky Way being consumed by the considerably bigger Andromeda Galaxy in the distant future. This simulation was produced by International Centre for Radio Astronomy Research. You can read more about it here.
Andromeda and the Milky Way Collide! from ICRAR on Vimeo.