A team led by Carnegie’s Scott S. Sheppard first spotted the moons in the spring of 2017 while they were on the hunt for a possible massive planet far beyond Pluto. In 2014 this same team found the object with the most distant known orbit in our Solar System and was the first to realize that an unknown massive planet at the fringes of our Solar System could explain the similarity of the orbits of several small extremely distant objects. This putative planet is sometimes called Planet X or Planet Nine. University of Hawaii’s Dave Tholen and Northern Arizona University’s Chad Trujillo are also part of the team. “Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant Solar System objects, so we were serendipitously able to look for new moons around Jupiter while at the same time looking for planets at the fringes of our Solar System,” Sheppard said. Gareth Williams at the International Astronomical Union’s Minor Planet Center used the team’s observations to calculate orbits for the newly found moons. “It takes several observations to confirm an object actually orbits around Jupiter,” Williams said. “So the whole process took a year.” New Moons of Jupitor Discovered— Twelve new moons orbiting Jupiter have been found, 11 “normal” outer moons and one “oddball” moon. This brings Jupiter’s total number of known moons to a whopping 79, the most of any planet in our Solar System. The discovery was widely covered by the media. The two moons orbiting in the same direction of Jupiter’s orbit, the prograde group, are shown in blue. The orbits of nine outer moons moving in the opposite direction, retrograde, are shown in red. The oddball, Valetudo, has an orbit that crosses the outer group and is at risk for head-on collisions. Image courtesy Roberto Molar Candanosa Unike the group of inner prograde moons, new prograde Valetudo has an orbit that crosses the retrogrades. Outer Moons of Jupiter Newly discovered moons shown in bold Galilean Moons Prograde Group Retrograde Group