Humans have long looked to the sky and wondered how many Earth-like worlds were out there. Thanks to powerful telescopes developed in recent years, both professional and amateur astronomers have discovered a plethora of planets orbiting other stars. In the three decades since the first confirmed exoplanet, they’ve indexed more than 4,000 — many of which sit at similar distances from their stars.
Read More: NASA’s Exoplanet-Hunting Space Telescope Needs Your Help Finding New Worlds
