Inflation resolves several outstanding problems in standard Big Bang cosmology. Among these are the observed flatness of the universe (the flatness problem), its extraordinary homogeneity on large (non-causally-connected) scales (the horizon problem), and its lack of any observed topological defects, predicted by many Grand Unified Theories.
Predictions of the standard model of inflation include geometrical flatness of the universe to high precision and scale invariance of the fluctuations in the cosmic microwave background. There are also consequences for high-energy particle physics near or at the GUT scale. During the 1980s, there were many attempts to relate the field that generates the vacuum energy to specific fields that were predicted by Grand Unified Theories or to use observations of the universe to constrain those theories. These efforts proved fruitless and the exact nature of the particle or field that generates the vacuum energy density for inflation (the "inflaton") remains a mystery.
The name of the theory was a semi-humorous reference to the economic inflation in the United States in the late 1970s.