Main   Terms   People   Interviews   Resources   Events

Big Bang Cosmology

A broad area of research that includes theories of the structure and development of the universe based upon Einstein’s theory of general relativity, which implies an expanding universe. The expansion of the universe was first confirmed in 1929 by Edwin Hubble’s observations of the retreating motion of galaxies.

During the decade following the publication of his special theory of relativity, Einstein worked on applying it to a dynamical theory of gravity. His basic insight was to reconceptualize gravity as the curvature of spacetime instead of as a (Newtonian) force in space. Rather than being deflecting from their otherwise linear motion in a Euclidean space with three dimensions, masses would move along geodesics describing the shortest possible path in curved spacetime. Their motion, in turn, would alter the curvature of spacetime, thus giving the field equations General Theory of Relativity (GR) their highly non-linear form aptly described as: ‘spacetime tells mass how to move; mass tells spacetime how to curve’.

Shortly after the discovery of GR, solutions to Einstein’s equations were developed for two distinct classes of problems: i) point masses, which when applied to the solar system led to several key tests of the theory and their eventual confirmation (including the deflection of starlight by the sun and the precession in the perihelion of the orbit of Mercury), and ii) dust, which when eventually applied to the distribution of galaxies and galactic clusters described the universe as expanding in time. During the 1920s, telescopic observations by Edwin Hubble showed that galaxies were indeed receding from us and at a velocity proportional to their distance. In essence, the expansion of the universe had been discovered!

There are in fact three types of expansion possible. i) Closed model: spherical. In one model the universe has the shape of a 3-dimensional sphere of finite size. It expands up to a maximum size, approximately 100 billion years from now, then recontracts, eventually recollapsing to a singularity that mirrors t=0 with infinite temperatures and densities. ii) Open model 1: ‘flat’ and iii) open model 2: ‘saddle-shaped’. Both the ‘flat’ and ‘saddle-shaped’ models are infinite in size and expanding in time. In both cases the universe will expand forever and cool indefinitely towards absolute zero. The future of these models is often used to characterize them as ‘freeze’ (open, both cases) or ‘fry’ (closed). All three came to be called “Big Bang” models because they describe the universe as having a finite past life of 10-20 billion years and beginning in an event of infinite temperature and density, and zero volume. Since the age of the universe, t, is calculated as starting here, it is convenient to label it “t=0"; technically this event is referred to as an “essential singularity.” In the 1960s, Stephen Hawking, Roger Penrose, and Robert Geroch proved key theorems which showed that the existence of an essential singularity, t=0, given Einstein’s GR, was unavoidable.

Related Topics:

Did the Universe Have a Beginning?

Contributed by: Robert Russell - CTNS

To return to the previous topic, click on your browser's 'Back' button.

Topic Sets Available

AAAS Report on Stem-Cells

AstroTheology: Religious Reflections on Extraterrestrial Life Forms

Agency: Human, Robotic and Divine
Becoming Human: Brain, Mind, Emergence
Big Bang Cosmology and Theology (GHC)
Cosmic Questions Interviews

Cosmos and Creator
Creativity, Spirituality and Computing Technologies
CTNS Content Home
Darwin: A Friend to Religion?
Demystifying Information Technology
Divine Action (GHC)
Dreams and Dreaming: Neuroscientific and Religious Visions'
E. Coli at the No Free Lunchroom
Engaging Extra-Terrestrial Intelligence: An Adventure in Astro-Ethics
Evangelical Atheism: a response to Richard Dawkins
Ecology and Christian Theology
Evolution: What Should We Teach Our Children in Our Schools?
Evolution and Providence
Evolution and Creation Survey
Evolution and Theology (GHC)
Evolution, Creation, and Semiotics

The Expelled Controversy
Faith and Reason: An Introduction
Faith in the Future: Religion, Aging, and Healthcare in the 21st Century

Francisco Ayala on Evolution

From Christian Passions to Scientific Emotions
Genetic Engineering and Food

Genetics and Ethics
Genetic Technologies - the Radical Revision of Human Existence and the Natural World

Genomics, Nanotechnology and Robotics
Getting Mind out of Meat
God and Creation: Jewish, Christian, and Muslim Perspectives on Big Bang Cosmology
God, Humanity and the Cosmos: A Textbook in Science and Religion
God the Spirit - and Natural Science
Historical Examples of the Science and Religion Debate (GHC)
History of Creationism
Intelligent Design Coming Clean

Issues for the Millennium: Cloning and Genetic Technologies
Jean Vanier of L'Arche
Nano-Technology and Nano-ethics
Natural Science and Christian Theology - A Select Bibliography
Neuroscience and the Soul
Outlines of the Science and Religion Debate (GHC)

Perspectives on Evolution

Physics and Theology
Quantum Mechanics and Theology (GHC)
Questions that Shape Our Future
Reductionism (GHC)
Reintroducing Teleology Into Science
Science and Suffering

Scientific Perspectives on Divine Action (CTNS/Vatican Series)

Space Exploration and Positive Stewardship

Stem-Cell Debate: Ethical Questions
Stem-Cell Ethics: A Theological Brief

Stem-Cell Questions
Theistic Evolution: A Christian Alternative to Atheism, Creationism, and Intelligent Design...
Theology and Science: Current Issues and Future Directions
Unscientific America: How science illiteracy threatens our future
Will ET End Religion?

Current Stats: topics: >2600, links: >300,000, video: 200 hours.