Jupiter has just delivered the news we desperately need right now. In addition to being the biggest, oldest planet in the solar system, it turns out Jupe has been hiding two moons from us all these years. Recently, a group of astronomers spotted the pair of wayward satellites, bringing the number of Jupiter’s known moons to 69.
Astronomer Scott Sheppard and his colleagues spotted S/2016 J 1 and S/2017 J 1 on March 8th, 2016 and March 23rd, 2017, respectively. The International Astronomical Union’s (IAU) Minor Planet Electronic Circulars announced both moons earlier this month.
“We were continuing our survey looking for very distant objects in the outer solar system, which includes looking for Planet X, and Jupiter just happened to be in the area we were looking in 2016 and 2017,” Sheppard told Sky and Telescope. Clearly, getting distracted by Jupiter paid off.
Not much is known about S/2016 J 1 and S/2017 J 1, except that they are very small—perhaps only one or two km (about 0.6 to 1.3 miles) across. S/2016 J 1 takes roughly 1.65 years to orbit Jupiter, while S/2017 J 1 takes about 2.01 years to do the same.
Hopefully, future research will give us more insight into these moons. But for now, as moons 68 and 69, they are irrefutably good. [Sky and Telescope]