A huge and unexpected surprise: A team of astronomers from the Carnegie Institute for Science has accidentally discovered 12 previously unknown moons orbiting the great giant Jupiter.
This brings the total of known Jovian moons to 79. The newly discovered satellites further increase Jupiter’s difference as the planet with the most moons in our entire solar system, as the space around Saturn is quite crowded.
The team, led by astronomer Scott S. Sheppard, was using ground-based telescopes to search for evidence of the mysterious Planet Nine , a hypothetical large icy planet that could exist beyond the orbit of Neptune, the most distant planet in the solar system.
“Jupiter was just in the sky near the search fields where we were looking for extremely distant objects,” Sheppard commented.
Thus, while searching for this mysterious planet, experts stumbled upon a dozen new moons orbiting Jupiter. 12 moons circling the planet in a suicidal orbit that will inevitably lead to its violent destruction at some point, experts say.
The team first glimpsed the moons in March last year from the Cerro Tololo Inter-American Observatory in Chile, but it took more than a year to confirm that the bodies were in orbit around the gas giant. “It was a long process,” Sheppard clarified.
The recent arrival of these natural satellites brings the total number of Jovian moons to 79, more than are known to surround any other planet in our cosmic neighborhood.
Nine of the new moons belong to an outer group that orbits Jupiter in retrograde orbit, which means they travel in the opposite direction as the planet’s spin. They are believed to be the remains of three parent bodies that broke apart in collisions with asteroids, comets, and other moons. It takes each one about two years to circle the planet.
Two more of the moons are in a group that rotates much closer to the planet, in prograded orbits, traveling in the same direction as Jupiter’s spin. Most likely they are fragments of a larger moon that broke apart in orbit. It takes this pair of moons almost a year to complete one revolution around Jupiter. (In which direction the moons rotate around the planet depends on how they were first captured by Jupiter’s gravitational field.)
Valetudo
Astronomers describe the twelfth new Jovian moon as a “weirdo.” At less than a kilometer wide, the small body circles Jupiter in a prodigious orbit but at a distance that means it crosses the path of other moons. Scientists have provisionally named this moon Valetudo , after the great-granddaughter of the Roman god Jupiter, the goddess of health and hygiene.
“Valetudo is like driving on the wrong side of the road,” Sheppard said. “It is moving in a prograde orbit while all other objects at a similar distance from Jupiter are moving in a retrograde orbit. So head-on collisions are likely.”
Sheppard, whose report is not yet available in a peer-reviewed journal, suspects Valetudo is the final remnant of a once much larger moon that was destroyed by collisions . The team is running computer simulations to try to figure out when Valetudo might collide with a retrograde moon.
“This simulation takes a few months to run, and we expect the answer to be between approximately 100 million years and one billion years, which although it is long in human time, it is not so long in astronomical time ,” Sheppard said.
“A full document will likely be written after these simulations are done in a few months.”
Reference: A dozen new moons of Jupiter discovered, including one ‘oddball’ 2018 Carnegie Institution for Science
