While we know Planet Earth has only one moon, Mercury and Venus have none, the outer planets Jupiter, Saturn, Uranus, and Neptune have quite a few.
On July 17, 2018, astronomers at the Carnegie Institution for Science confirmed that they have accidentally discovered 12 new moons orbiting Jupiter. These 12 additional moons bring the known tally of Jupiter’s moons to 79.
Astronomers said they accidentally discovered these new moons while searching the outer solar system for smaller objects and planets lurking beyond Pluto. They used a 4-meter Víctor Blanco Telescope in an observatory in Chile.
The only things they know about them are their approximate sizes and the shape of their orbits. The twelve moons are very very tiny, just a couple miles across or smaller.
Interestingly, eleven of the 12 moons remain nameless, but one of them is special! This special guy has been named Valetudo after the Roman God Jupiter’s great-granddaughter.
Why is Valetudo special?
Two of the 12 moons discovered are part of the Prograde group. They are moons closer to Jupiter and tend to orbit in a “prograde” motion, meaning in the same direction as Jupiter’s rotation.
Nine of the 12 moons discovered were found in the outer Retrograde group. They are farther away and move in a “retrograde” motion i.e. in the opposite direction to Jupiter’s rotation.
The special one, Valetudo was found orbiting in a prograde motion in the retrograde region. Oops! Lead astronomer Scott Sheppard says it’s like Valetudo is driving down the highway the wrong way!
This means that Valetudo is sure to collide with one of the moons at some point. That also might explain why astronomers keep discovering smaller moons orbiting Jupiter. One theory is that there were probably fewer, larger moons orbiting Jupiter in this retrograde region but over time collisions have broken them into pieces.
Hopefully, these tiny moons will help astronomers learn more about Jupiter’s past.
Credit: Carnegie Institution for Science
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Adapted By Biyash Choksey