Alien Worlds (S09E04)

Ancient civilizations speculated that the universe was filled with countless unseen worlds and engaged in endless debates about the characteristics of these distant, invisible planets and the possibility of life existing on them. For a long time, many scientists were convinced that we would never uncover the truth, as they thought extra-solar planets were too far away, too small, and too dim for detection. However, advancements in technology have recently unveiled thousands of these remote planets, ushering in an exhilarating era for astronomy. Some believe we may finally be close to answering the age-old question: are we alone in the cosmos?