NASA’s news of the TRAPPIST-1 solar system generated quite the buzz recently. The agency announced that the system’s star — an ultra-cool dwarf just a bit bigger than Jupiter — has a collection of seven Earth-sized planets circling it. Researchers confirmed two of these planets in 2016 but upped the tally to seven after they gathered more data. Three of the worlds lie in the star’s habitable zone, where there is the greatest likelihood of having liquid water and maybe even life. But researchers say water may exist on all seven planets, which, at the time of this writing, are still unnamed.