Astronomers from NASA and the European Southern Observatory announced Wednesday that four new Earth-sized exoplanets have been discovered orbiting a star about 40 light-years away, and that three may contain liquid water and be able to sustain life. This star’s small grouping of planets now boasts the most Earth-sized worlds of any system astronomers have discovered, and the most exoplanets that may be able to support surface life and water.
A Belgian-led team was able to spy these planets using space- and ground-based telescopes as each passed in front of its host, a red dwarf star known as TRAPPIST-1. These so called transits created dips in the Jupiter-sized star’s light output that helped astronomers determine the sizes, compositions, and orbits of each of the celestial bodies. “Whether or not TRAPPIST-1 has inhabitants, its discovery has underlined the growing conviction that the universe is replete with real estate on which biology could both arise and flourish,” says Seth Shostak of the SETI Institute, an expert in the search for extraterrestrial life. “If you still think the rest of the universe is sterile, you are surely singular, and probably wrong.”