Thanks to the NASA / ESA ‘Hubble’ space telescope, an international group of astronomers has discovered the first signs of water in the TRAPPIST 1 system .
As you may recall, this system discovered earlier in the year is home to seven Earth-sized planets.
Possibly habitable
On February 22, 2017, astronomers announced the discovery of seven Earth-size planets orbiting the ultrathin dwarf star TRAPPIST-1, 40 light-years away .
The finding of signs of water , led by the Swiss astronomer Vincent Bourrier of the Observatory of the University of Geneva, is important because it improves the probability that these planets are habitable .
The finding has been made with the Space Telescope Imaging Spectrograph (STIS) at NASA’s Hubble Space Telescope and ESA to study the amount of ultraviolet radiation received by the planets of the system. According to Bourrier , "ultraviolet light from stars can break water vapor into hydrogen and oxygen" and, being light, hydrogen gas can escape from the atmosphere of exoplanets and be detected in the surroundings with telescopes as has done the Hubble.