Inflationary universe

Definition

The inflationary universe is a theory that proposes a period of extremely rapid exponential expansion of the universe immediately following the Big Bang. It explains several key cosmological observations such as the uniformity of the cosmic microwave background radiation and the large-scale structure of the cosmos.

5 Must Know Facts For Your Next Test

1. Inflation occurred within a tiny fraction of a second after the Big Bang, around 10^-36 to 10^-32 seconds.
2. The theory was proposed by physicist Alan Guth in 1981.
3. Inflation solves the horizon problem by explaining why regions of space that are now far apart have nearly identical properties.
4. It also addresses the flatness problem, suggesting that inflation drove the universe towards a flat geometry.
5. Quantum fluctuations during inflation led to small density variations, which later grew into galaxies and large-scale structures.

Review Questions

• What time frame does inflationary theory suggest for when rapid expansion occurred after the Big Bang?
• Who proposed the theory of an inflationary universe and in what year?
• How does inflationary theory explain the uniformity observed in cosmic microwave background radiation?

Related terms

Big Bang Theory:

A scientific theory describing how the universe expanded from an extremely hot and dense initial state.

Cosmic Microwave Background (CMB): Radiation left over from an early stage in the development of the universe, often considered as evidence for the Big Bang.

Horizon Problem:

A cosmological issue regarding why distant regions of space have similar temperatures despite being out of causal contact with each other.