Back in February, NASA announced the discovery of Trappist-1, a solar system with seven Earth-like planets that may contain water. Now, an international team of scientists has found further evidence that these planets might be habitable. Using data from Space Telescope Imaging Spectograph (STIS) on the Hubble Space Telescope, the scientists investigated the amounts of ultraviolet radiation impacting each planet in the system, which could provide further insights into their atmospheres. From the STIS data, they were able detect escaped hydrogen gas around the atmosphere of each planet, which helps to determine the likelihood of atmospheric water vapour, and found that the two innermost planets could have lost vast amounts of water — as much as 20 Earth-oceans worth over the last 8 billion years, and that the five remaining planets, including the three in the system's habitable zone, have lost much less water and might still have some water remaining on their surfaces. To find out more check out Hubble delivers first hints of possible water content of TRAPPIST-1 planets.