A contemporary cosmology of the universe is based on the theory of general relativity, which includes a creation event, a first event. Using the equations of general relativity, it is possible to trace the origin of the universe backward in time to an estimated beginning point, a first event. The big bang as a first event is viewed as the beginning of the universe and more specifically as the beginning of time. As a result of the big bang, the universe is continually expanding and changing because galaxies are moving away from each other at high speeds. In the big bang cosmology, time is finite and has a specific beginning point and a possible ending as the expansion that began with the big bang comes slowly to an end due to gravitational forces. A series of photos collected from the Keck and Hubble space telescopes show the universe in the various phases of expanding from the time before galaxies existed to newly formed galaxies tightly packed together and still colliding, to the current stage of development when there are few new star formations, and galaxy collisions are less frequent. It is believed that photos have captured the moment in cosmic history when the universe was only 300,000 years old. At that moment, light is thought to have separated from darkness, a description that some contemporary theologians believe fits the biblical account of Creation.
The big bang theory was proposed in 1946 by George Gamow, a Russian scientist, who identified the big bang as an exploding, primeval fireball that contained the entire physical universe, including the dimensions of time and space. In 1965, observations at the Bell Telephone Laboratories of a ubiquitous background radiation provided convincing evidence of the validity of the big bang theory. In 1992 the NASA (National Aeronautics and Space Administration) satellite Cosmic Background Explorer provided additional evidence that placed the beginning of the universe at about 15 billion years ago. In the 1970s the work of Stephen Hawking and Roger Penrose helped to prove that time is finite in a universe with an identifiable beginning event and possible predictable ending. Using mathematical calculations to establish the presence of mass in the universe and the general relativity theory of Einstein to show how mass can be expected to behave, Hawking and Penrose established that time is finite and must have started when the universe began. Hawking defines an event as something that happens at a particular point in space and at a particular time. For Hawking, time and space begin together in the big bang and therefore are never truly separate. He refers to space and time together as spacetime. Hawking’s description of the big bang as the “singular boundary” for space and time is known as the singular boundary theorem. For some philosophers and theologians, the spacetime theorem lends itself to the argument for the existence of God because the concurrent beginning of the universe and time make it necessary to find a first cause. For many theologians, the first cause can only be a deity who transcends time and all other dimensions of the cosmos, including space, matter, and energy. While it is not necessary to narrowly define the first cause as the God of the Christian Bible, many philosophers and theists agree that it is not possible for something to come out of absolutely nothing; therefore, the universe must have a cause that existed before the big bang. The big bang theory of the universe requires a transcendent force that is separate from the universe to bring the universe into being. Without endorsing any theological beliefs, many physicists acknowledge the
need for a universe with a beginning and a pre-big bang first cause or superior reasoning power. Some members of the scientific community continue to argue for a static or steady-state universe where time and space are still absolute and separate according to the calculations proposed by Isaac Newton. However, for some cosmologists, this universe may be cyclical and therefore does not require a beginning in time or a transcendent ultimate force.
Elaine M. Reeves
See also Big Bang Theory; Black Holes; Causality; Cosmogony; Cosmology, Inflationary; Einstein and Newton; Hawking, Stephen; Time, Arrow of; Time, Emergence of; Time, End of; Universes, Baby
Gribbin, J. (1999). The birth of time: How we measured the age of the universe. New Haven, CT: Yale University Press.
Hawking, S. H. (1988). A brief history of time: From the big bang to black holes. New York: Bantam Books.
Trinh, X. T. (1993). The birth of the universe: The big bang and after. New York: Abrams.