The orbit of a dozen previously unknown moons around Jupiter are shown here, including the "oddball" discovery, Valetudo.
Astronomers suspect that the retrograde moons may be the remains of larger moons that were destroyed in head-on collisions with prograde objects. Some of the outer moons, on the other hand, are retrograde moons, which orbit in the opposite direction.
Jupiter, the largest planet in the solar system, was hardly short of moons before the latest findings.
The team is calling one of the new moons an "oddball" because of its unusual orbit.
The renegade moon has an inclined orbit that crosses those of others moving in the opposite direction, greatly increasing the possibility of a collision.
"This is an unstable situation", said Sheppard.
A head-on collision between two moons would "grind the objects down to dust", he added. These inner prograde moons all have similar orbital distances and angles of inclinations around Jupiter and so are thought to also be fragments of a larger moon that was broken apart.
The new moons were first glimpsed in 2017, using a telescope based in Chile and operated by the National Optical Astronomical Observatory of the United States. Seven fall in a farther out "retrograde" cluster (red) rotating against the planet's spin, their opposing path kickstarted when ancient moons collided with comets, asteroids, or other moons. And more than a third of those belong to a single planet: Jupiter.
Though most of the moons were originally spotted using the Blanco 4-meter telescope, several other telescopes, in Chile, Arizona and Hawaii, were used to confirm the presence of the Jovian satellites.
It has an angled prograde orbit that takes about a year and a half to complete.
Jupiter's moons range in size from shrimpy satellites to whopping space hulks. Two of the newly discovered moons were found among these prograde moons, and take a little less than a year to go around in their orbit once.
Many prior studies have suggested that Jupiter has greatly influenced the evolution of the solar system.
The discovery of these moons came from a totally different search for new solar system bodies.
It's been nicknamed Valetudo after the Roman goddess of health and hygiene who is the great-granddaughter of the god Jupiter.
Sheppard said the oddball moon is "likely Jupiter's smallest known moon, being less than 1 kilometre in diameter".
The moon we see today is the remainder of a much bigger world that blew apart after the crashes. The lost moons were initially sighted in 2003, but scientists could not define their exact orbits and lost track of them. Scientists believe it could be the last remaining remnant of a once larger moon that was involved in past collisions.
According to Horner, if Valetudo had formed early on, it would have been slowed by the gas and dust present at the formation of Jupiter, and fallen into the planet. "We think these moons are an intermediate type of object, half-rock and half-ice". The telescope recently was upgraded with the Dark Energy Camera, making it a powerful tool for surveying the night sky for faint objects.