Space is cool
The Hubble Telescope team has discovered the potential for "substantial amounts of water" on four of seven Earth-sized planets found earlier this year, Axios writes. The system of planets orbits a star called TRAPPIST-1 and is about 40 light years from our own planet.
By measuring the ultraviolet light on the planets and the amount of hydrogen leaving them, "results suggest the innermost planets, TRAPPIST-1B and TRAPPIST-1C, could have lost as much as 20 Earth-oceans-worth of water in the last eight billion years," Popular Mechanics writes. "The outer planets, however, including E, F, and G, which orbit in the habitable zone, would have lost less water, and could still retain vast stores of liquid water on the surface."
Even stranger, the potentially habitable planets all appear to be "tidally locked" with TRAPPIST-1, meaning half the planet exists in unending day and the other in unending night.
The data collected by Hubble "concludes that a few of these outer planets could have been able to hold onto some water, if they accumulated enough during their formation," said Julien de Wit, one of the researchers involved in the study. "But we need to gather more information and actually see a hint of water, which we haven't found yet." Read more about the discovery at Popular Mechanics.