Jupiter’s first moons were discovered by Italian scientist Galileo Galilei in 1610. However, more and more moons have been discovered since. This means that we’re just barely scratching the surface behind the mysteries of this great gas giant.
In July of 2018, scientists discovered 10 new moons around Jupiter, which brings the number of moons now to 79.
Of the new moons, one seems to have a strange orbit that could help astronomers figure out how the moons of Jupiter were formed.
Scott Sheppard of Carnegie Institution for Science has been on the lookout for Planet Nine, which is theorized to exist in the far reaches of the Solar System. By chance, Sheppard’s team saw Jupiter in orbit in 2017, whereupon the Blanco 4-meter telescope Sheppard being used caught sight of strange objects moving around the gas giant. The telescope was fit for spotting new moons due to its built-in camera. This makes taking photos of Jupiter’s skies is easier, thus increasing the chances of finding more moons and other floating objects.
There was one moon that caught their eye, Valetudo. Sheppard gave the name, and the moon was shown to be moving in a different direction from the rest. Most moons orbit in a similar way to the others near them. The four Galilean moons closest to Jupiter follow the same direction as the rotation of the planet in what is called a prograde orbit. The outer moons do the opposite, a retrograde orbit, and this pattern has been observed in the new moons, except Valetudo. Theories suggest that Valetudo might have gone through a head-on collision long ago or that it was a leftover of a larger moon that rammed into another satellite. Collision causes chunks of larger moons to form as separate moons.
This find tells us a lot about how the early solar system was. Before the giant planets were formed, the system was a large disk of dust and gas surrounding the Sun, which was still at its infancy. Sheppard notes that the moons could be leftovers of the giant planets after they had fully formed.