There may be a new contender for the likeliest place to host life elsewhere in our solar system—and it's not a planet or a moon. Astronomers have spotted water vapor from Ceres, classed as both the smallest dwarf planet and largest asteroid, marking the first time water has been confirmed in the asteroid belt between Mars and Jupiter, reports the Los Angeles Times. The find suggests that internal energy is heating water from Ceres' interior, meaning there could also be a subsurface ocean capable of hosting life.
"This is what you might call the 'smoking gun,'" the chief of the Planetary Science Institute tells NBC. "The implications could be huge for the future of astrobiology and planetary exploration." The find "raises the possibility that Ceres could replace Europa as the prime target for planetary investigation," he says. "It's going to upend the cart a bit, but that's science." The vapor is steaming off Ceres at a rate so high that scientists believe it could contain more fresh water than Earth, backing up the theory that our planet's water was brought by asteroids. Astronomers will be able to take a closer look when NASA's Dawn spacecraft reaches Ceres next spring. (Read more Ceres stories.)