19-01 The Inflation Hypothesis
- How can the CMB be so isotropic over the sky? -- the horizon problem.
[The cosmic light horizon; the observable universe]
- How can the cosmic energy density be so close to unity? -- the flatness problem.
- To solve the above two problems, the idea of inflation was proposed independently
by Alexei Starobinsky in Russia and by Alan Guth in the US in early 1980s.
[During a very brief period of time (~ 10-32 s) shortly after the big bang,
the universe expands by a factor of 1050.]
- There are alternative models without inflation.
Future observation of CMB polarization may help to discriminate these models.