Cosmology is used as a term for the study of the universe as a whole by using different scientific methods to understand it. Cosmologists make hypotheses about specific phenomena in the universe which they later on try to test via observations. Then the hypotheses are either abandoned, revised or extended according to the data obtained from the observations. Physics and astrophysics are combined in physical cosmology which means that is uses both simple observations as well as mathematical tools to investigate the universe as one unit. More specifically, physical cosmology helps to understand the universe through observation and experiment.

The observation of the large- scale structure of the universe is the basis for the knowledge gained about how the cosmos was formulated and how it evolved. The most common view on the birth of the cosmos is the Big Bang theory according to what the whole universe was created in a single point of time and after that started to expand until it reached its current condition and many believe that it is still expanding and will continue to do so in the future. Cosmology also tries to predict the fate of the universe. Cosmologists state that from the beginning of the universe until the many theories how it will end, the universe has been growing like the physical laws state it would.