Jupiter Now Has 69 Moons, an addition of two

Until recently the cataloged satellites totaled 67 in number. But only the innermost 15 of these orbit Jupiter in a prograde sense (in the direction of the planet's spin). The rest are retrograde, and are likely captured objects - other pieces of the solar system's solid inventory that strayed into Jupiter's gravitational grasp.

                                                          The big boys

That population of outer moons is mostly small stuff, only a few are 20-60 kilometers in diameter, most are barely 1-2 kilometers in size, and increasingly difficult to spot.

Now astronomers Scott Sheppard, David Tholen, and Chadwick Trujillo have added two more; bringing Jupiter's moon count to 69. 

These additions are also about 1-2 km in size, and were spotted in images that were part of a survey for much more distant objects out in the Kuiper Belt. Jupiter just happened to be conveniently close in the sky at the time. The moons are S/2016 J1 and S/2017 J1, and are about 21 million km and 24 million km from Jupiter.

By themselves these small satellites don't amount to much. But they are a vivid reminder of the sheer abundance of material out there in our solar system, and of Jupiter's royal gravitational status.