Galaxy formation is hypothesized to occur, from structure formation theories, because of tiny quantum fluctuations in the aftermath of the Large Bang. The simplest model for this that is in general agreement with observed phenomena is the Chilled Dark Matter cosmology; that is to say that clustering and merging is how galaxies gain in mass, and can also select their shape and structure.
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies modify over time, and the processes that have generated the variety of structures observed in nearby galaxies. It is of the most active research areas in astrophysics.
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies modify over time, and the processes that have generated the variety of structures observed in nearby galaxies. It is of the most active research areas in astrophysics.