Twenty years ago astronomers discovered the first planet around a sun-like star, 51 Pegasi b. And in the last 20 years, astronomers have discovered thousands of new exotic worlds, begun to characterize atmospheres of faraway planets, and are developing cutting-edge technology to launch us on our search for alien life. Planets with two suns, rogue planets with no star, close cousins to planet Earth. This is the story of the pioneers in planet-hunting and how those who have followed are closer to answering one of humanity’s most ancient questions: Is there life elsewhere in the universe?

Credit: Exoplanet Exploration Communications Team / planetquest.jpl.nasa.gov