A single dim star turned out to host seven Earth-sized planets
In 2017, astronomers announced that TRAPPIST-1, a small, cool dwarf star 40 light-years away, hosts seven roughly Earth-sized planets, more than any other known system at the time. Three orbit in the star's habitable zone, where liquid water could survive, making the tightly packed system one of the best targets yet in the search for life beyond Earth.