How did physical nature on the cosmic scale begin? What are the dimensions of the universe? These remain the two most persistent and expansive scientific questions in the collective mind of humanity. Logically, they seem to be related to each other,...

Big bang theory describes the origin of the knowable universe and the development of the laws of physics and chemistry some 15 billion years ago. During the 1940s Russian-born American cosmologist and nuclear physicist George Gamow (1904–1968)...

The Big Bang Theory is the prevailing theory of the origin of the universe, and it is based on astronomical observations. According to this theory, about 15 billion years ago all the matter and energy in the visible universe was concentrated in a...

The big bang is the cosmic event that is theorized to have marked the origin of the universe. At that instant all matter and energy in the entire physical universe, and the four dimensions of time and space, were created from a state of enormous...

Before the twentieth century, astronomers could only assume that the universe had existed forever without change, or that it was created in its present condition by divine action at some arbitrary time. Evidence that the universe may be evolving did...

The standard model of cosmology is the big bang theory. It refers to the event, between 8 and 15 billion years ago, in which the universe was born in a cataclysmic explosion. In the aftermath, planets, stars, and galaxies slowly formed as the...

The Big Bang is the cosmological model of the universe whose primary assertion is that the universe has expanded into its current state from a primordial condition of enormous density and temperature. The term is also used in a narrower sense to...