Cosmic Inflation

A hypothesised burst of exponential expansion in the first fraction of a second that would explain the Universe's uniformity and flatness.

Inflation proposes that the very early Universe expanded by a factor of at least 10²⁶ in a tiny fraction of a second. It elegantly explains why the Universe looks so uniform, why space is geometrically flat, and how quantum fluctuations were stretched into the seeds of galaxies imprinted on the cosmic microwave background.

Proposed by Alan Guth in 1980 and refined by Andrei Linde, Andreas Albrecht, and Paul Steinhardt.

• The flatness of space
• The large-scale uniformity of the CMB
• The near-scale-invariant spectrum of primordial fluctuations measured by WMAP and Planck

• Did inflation actually occur?
• What physical field drove it?
• Are there primordial gravitational waves to detect?

• Depends onSpacetime
• PredictsThe Cosmic Microwave Background
• Part of modelThe Lambda-CDM Model
• Depends onGeneral Relativity
• Measured byWMAP (Wilkinson Microwave Anisotropy Probe)
• Measured byPlanck
• Required byStructure Formation
• Required byThe Lambda-CDM Model
• Related toThe Multiverse
• Related toCyclic & Bouncing Cosmologies
• Preceded byThe Big Bang
• Followed byBig Bang Nucleosynthesis
• Associated withScalar Spectral Index (ns)
• Associated withQuantum Fluctuations