Inflation Theory is a concept in cosmology that suggests the universe underwent a rapid expansion shortly after the Big Bang. This expansion, which occurred in a fraction of a second, helped to explain the uniformity of the universe and the distribution of galaxies. It addresses why the universe appears flat and homogeneous on large scales. The theory was first proposed by physicist Alan Guth in the 1980s. It posits that a field called the inflaton field drove this exponential growth, smoothing out any irregularities. This idea has been supported by observations of the cosmic microwave background radiation, providing insights into the early universe's conditions.