ABSTRACT
This chapter shows how the basic level several puzzles are resolved in the framework of the inflationary scenario. It also shows some of the puzzles of the standard Big Bang model can be resolved if the universe underwent a phase of accelerated exponential expansion. Different models have been proposed in the literature over the past 30 years. In 1981 Guth A. H. showed how a first-order phase transition could generate an inflationary phase. The chapter discusses two inflationary models: a power law inflation and a power law potential to see how it is possible in the framework of these scenarios to resolve the puzzles of the Big Bang model. There is another added value of the inflationary scenario: the generation of the spatial inhomogeneities responsible for the formation and evolution of the large-scale structure of the universe. The chapter also discusses these aspects as well as the observational constraints from cosmic microwave background observations.
