Researchers in the USA stumbled upon the new moons while hunting for a mysterious ninth planet that is postulated to lurk far beyond the orbit of Neptune, the most distant planet in the solar system. We're using the most advanced digital cameras in the world ... And after follow-up observations, they've confirmed that Jupiter has even more moons than we thought. As for the number of satellites that orbit Jupiter, Williams said he dreads "to think how many objects are in the hundred-meter range".
The announcement of the new moons was published Tuesday in the International Astronomical Union Minor Planet Electronic Circular. Each takes about two years to circle the planet.
Two of the new discoveries are part of a closer, inner group of moons that orbit in the prograde, or same direction as the planet's rotation.
For example, the discovery that the smallest moons in Jupiter's various orbital groups are still abundant suggests the collisions that created them occurred after the era of planet formation, when the Sun was still surrounded by a rotating disk of gas and dust from which the planets were born.
"This is an unstable situation", said Sheppard. Nine of the new satellites orbit in a distant swarm of outer moons that are thought to be leftover from a series of collisions that might have involved what were once three larger bodies. "What these other objects were has been a mystery".
Astronomers describe the twelfth new Jovian moon as an "oddball". Of the twelve, only three moons orbit in a prograde direction, and are closer to Jupiter. But it's not part of the same group.
Jupiter, the largest planet in the solar system, was hardly short of moons before the latest findings.
"Our other discovery is a real oddball and has an orbit like no other known Jovian moon", Sheppard explained.
Valetudo is more than just the odd moon out; it's also a serious collision hazard.
The remaining moon is less than a kilometer across, further out than the two conventional moons and has a 1.5-year orbit-and the orbit is inclined. The satellite, named for Jupiter's great-granddaughter, could be a bit of unfinished business, the last remnant of the ancient moons that provided the grist for the retrograde cluster, the team theorizes. The "oddball" moon, known as Valetudo, can be seen in green in a prograde orbit that crosses over the retrograde orbits. "If one did happen, we would be able to detect it from Earth, but it is unlikely to happen anytime soon".
"What's really cool for me here is what they're calling their oddball", Horner told ScienceAlert. Their existence shows that they were likely formed after this gas and dust dissipated.
Our solar system is already teaming with almost 200 moons, and we just got 12 more to add to the list.
The team's results are not yet available in a peer-reviewed journal, as Sheppard's team is now running supercomputer simulations to try and figure out how often Valetudo might collide with a retrograde moon. The astronomers are now running computer simulations to determine how the ancient moons fragmented.
"A full paper will likely be written after these simulations are done in a few months".
Of the 12 newly discovered moons, 11 are "normal, "according to a statement from the Carnegie Institution for Science".