Richard Tolman

The cyclic model is a brane cosmology model of the creation of the universe, derived from the earlier ekpyrotic model. It was proposed in 2001 by Paul Steinhardt and Neil Turok. Cyclic model - The model. In the cyclic model, two parallel orbifold planes or M-branes collide periodically in a higher dimensional space. The visible four-dimensional universe lies on one of these branes. The collisions correspond to a reversal from contraction to expansion, or a big crunch followed immediately by a big ba ...

Including:

• Cyclic model - The model

Read more here: » Cyclic model: Encyclopedia - Cyclic model

Observationally, in the 1910s, Vesto Slipher and later Carl Wilhelm Wirtz determined that most spiral nebulae were receding from Earth. Slipher used spectroscopy to investigate the rotation periods of planets, the composition of planetary atmospheres, and was the first to observe the radial velocities of galaxies. Wirtz observed a systematic redshift of nebulae, which was difficult to interpret in terms of a cosmology in which the Universe is filled more or less uniformly with stars and nebulae. They weren't aware of the cosmological implications, nor that the supp ...

See also:

History of the Big Bang, History of the Big Bang - Prior to the 20th Century, History of the Big Bang - Early 20th Century, History of the Big Bang - Late 20th Century, History of the Big Bang - Future of the theory

Read more here: » History of the Big Bang: Encyclopedia II - History of the Big Bang - Early 20th Century

Much of the current work in cosmology includes understanding how galaxies form in the context of the Big Bang, understanding what happened at the Big Bang, and reconciling observations with the basic theory. In the past there was much discussion as to whether the Big Bang would need to be completely abandoned as a description of the universe, but such proponents of non-standard cosmology have become fewer in number over the last few decades. Cosmologists continue to calculate many of the parameters of the Big Bang to a new level of precision and hypot ...

See also:

History of the Big Bang, History of the Big Bang - Prior to the 20th Century, History of the Big Bang - Early 20th Century, History of the Big Bang - Late 20th Century, History of the Big Bang - Future of the theory

Read more here: » History of the Big Bang: Encyclopedia II - History of the Big Bang - Future of the theory