By Marina Wang

Researchers from the Carnegie Institute of Science have “serendipitously” stumbled upon 12 new moons of Jupiter, one was which was described as an “oddball”. The “oddball” moon could collide with one of Jupiter’s 79 other moons in a crash that could be detectable from Earth.

The researchers were searching for the mysterious Planet X, or Planet Nine, which is hypothesized to exist in the furthest reaches of our solar system, far beyond Neptune. “Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant Solar System objects, so we were serendipitously able to look for new moons around Jupiter while at the same time looking for planets at the fringes of our Solar System,” said Scott Sheppard, who led the research team.

It took the researchers over a year to confirm with multiple telescopes the discovery of Jupiter’s new moons.
Of the 12 newly discovered moons, nine orbit the outer ring and move in retrograde, or the opposite direction from Jupiter’s rotation. It takes around 2 years for these planets to orbit the planet. Two of the newly discovered moons are in the inner circle of moons and orbit in prograde, or in the same direction as Jupiter’s rotation. These take around a year to complete an orbit.

The “oddball” planet lies in between the inner and outer circles of moons: it orbits Jupiter in prograde and takes around a year and a half to orbit Jupiter. This new moon, called Valetudo after Roman God Jupiter’s great granddaughter and goddess of health and hygiene, will cross paths with Jupiter’s outer moons moving in the opposite direction. Valetudo is also one of Jupiter’s smallest moon, at less than a kilometre in diameter.

“This is an unstable situation,” said Sheppard. “Head-on collisions would quickly break apart and grind the objects down to dust.”

However, don’t hold your breath waiting to witness Valetudo crash with one of its neighbors—Sheppard has said that collisions only occur about once in a billion years.