In the Star Trek universe, habitable worlds abound, fueling the adventures of the intrepid crew of the starship Enterprise. In the latest movie, Star Trek Beyond, much of the action takes place on Altamid, a rugged wilderness world filled with exotic forests and perilous canyons and mountains.
Across the franchise, such Earth-like worlds are designated as M-class planets, a fictional classification derived from the Vulcan word Minshara.
Trek fans will know many examples of famous class M-class planets, such as Vulcan, Romulus, and Qo’noS, the home worlds of key alien species. While many of these worlds were conjured up by the show’s writers decades ago, today’s planet-hunting astronomers are finding scores of real-life counterparts outside our solar system. (Find out what else the fictional Star Trek universe got right about real-world science.)
Rocky planets like Earth are relatively puny compared to their host stars, making these worlds hard to see and even harder to characterize. But in the last two decades, astronomers have successfully developed indirect detection methods to find ever smaller, more Earth-like planets. Today the tally of confirmed alien worlds has reached nearly 3,000, with a handful that are considered rocky and potentially habitable.