Cosmology is the study of the structure and formation of the universe.
Ancient and medieval cosmologists were common, usually oriented around a world view of a stationary, flat earth as the center of the universe. Aristarchus understood that the earth was spherical and circled the sun. With the increasing sophistication of observing techniques and equipment, a more modern understanding of the universe emerged.
Much of modern cosmology is atheistic, which rejects God as explanations for the existence of the universe. Instead it uses theories such as relativity and the Big Bang theory based on the recession of galaxies shown by Red Shift. Atheistic cosmology occurs in a time frame which predates that suggested by creation scientists of approximately 6000 years. Some secular scientists also advocate the Steady state theory, though this is very small in comparison. Some also suggest a cyclic universe of expansion followed by contraction, repeating to infinity. This approach has no need for a supernatural creator (God) and avoids the problem of creation. A small number believe that the universe is in fact a highly advanced computer simulation.
The New American Desk Encyclopedia, Penguin Group, 1989