The Rare Earth hypothesis states that Earth-like planets, which harbor complex life, are rare due to the intricacies involved in the formation of a planet that meets the criteria to create life. The hypothesis details the low probability of planets forming in the same way as Earth.
It also states that there is a narrow area in the galaxy in which these planets exist, which is known as the Galactic Habitable Zone. Followers of this hypothesis believe that it answers the questions of why humans have yet to make contact with life on another planet. Copernican theory states that Earth is a typical rocky planet, but the Rare Earth Hypothesis offers reasons why similar planets do not have Earth-like life.