The Inflation Theory proposes a period of extremely rapid (exponential) expansion of the universe shortly after the Big Bang.
Limitations of the Big Bang Theory
While the Big Bang theory successfully explains the shape of the cosmic microwave background spectrum and the origin of the light elements, it leaves open a number of important questions:
- Why is the universe so uniform on the largest length scales?
is the physical scale of the universe so much larger than the fundamental
scale of gravity, the Planck length, which is one billionth of one trillionth
of the size of an atomic nucleus?
- Why are there so many photons in the universe?
- What physical process produced the initial fluctuations in the density of matter?
The Inflation Theory
Inflation Theory, developed by Alan Guth, Andrei Linde, Paul Steinhardt,
and Andy Albrecht, offers answers to these questions and several other open
questions in cosmology. It proposes a period of extremely rapid (exponential)
expansion of the universe shortly after the Big Bang, during which time the
energy density of the universe was dominated by a cosmological constant
term that later decayed to produce the matter and radiation that fill the
universe today. The Inflation Theory links important ideas in modern physics,
such as symmetry breaking and phase transitions, to cosmology.
Predictions of the Inflation Theory
In its simplest form, the Inflation Theory makes a number of important predictions:
- That the density of the universe is close to the critical density, and thus the geometry of the universe is flat.
- That the fluctuations in the primordial density in the early universe had the same amplitude on all physical scales.
there should be, on average, equal numbers of hot and cold spots in the fluctuations
of the cosmic microwave background temperature.
WMAP tests these predictions.
- Alan H. Guth & Paul J.Steinhardt, "The Inflationary Universe", Scientific American, May 1984.
- Andrei Linde, "The Self-Reproducing Inflationary Universe", Scientific American, November 1994.
- Gary Watson, "An Exposition on Inflationary Cosmology", WWWarticle, 2000.
- Alan H. Guth, "The Inflationary Universe : The Quest for a New Theory of Cosmic Origins", 1998.
Last updated: Tuesday, 03-01-2005