Cosmology

Cosmology is the study of the larger issues: how "big" is the Universe, does it have an "end", what is its large-scale structure, how old is the Universe, how long will it live?

Cosmology is the study of the origin and the development of the Universe. As such, it is concerned with the large scale, both with respect to distance, and with respect to the past and future for the Universe.

The Central Themes of Modern Cosmology

The central tenet of modern cosmology is the idea that the Universe is expanding, and that this implies that at some time in the distant past it was incredibly dense and hot. This "explosion" from a hot, dense initial state is called the big bang (or sometimes the hot big bang, to emphasize the high temperature during its occurrence). Some of the most important problems in cosmology are associated with understanding how galaxies and clusters of galaxies formed, and determining the nature of the mass of the Universe (we can only identify 10 percent of what we know from its gravitational influence must be there!).