Did Cosmic Inflation Really Happen?
According to the most widely accepted ‘big bang’ model for the origin of the universe, just 10-32 seconds after its birth, the universe underwent a very short but frantic period of exponential growth, called cosmic inflation.
Inflation explains why our universe is ‘flat’ (and why we learn Euclidean geometry in school) and why the temperature of the cosmic background radiation – released when protons and electrons first combined when the universe was 380,000 years old – is so uniform across the sky. It also helps to explain why this radiation nevertheless contains some tiny temperature variations, thought to be the result of quantum fluctuations imprinted on the universe and blown up by inflation, like a giant thumb-print left at a cosmic crime scene.
But did inflation really happen? The simple truth is we don’t know. In March 2014 scientists working on the Background Imaging of Extragalactic Polarization (BICEP2) experiment announced they had found its tell-tale signature. But in September 2014 Planck satellite mission scientists claimed that most (if not all) of the signal seen by BICEP2 is due to scattering by intergalactic dust.
The jury is still out.