Published: Mon, July 23, 2018
Research | By Wilma Wheeler

'Oddball' Moon Among 12 New Discoveries Orbiting Jupiter

'Oddball' Moon Among 12 New Discoveries Orbiting Jupiter

During a quest to find Planet Nine, a mysterious planet believed to be on the edge of our solar system, astronomers discovered something else: 12 new moons around Jupiter.

This, as you can imagine, has the potential to end poorly for our oddball friend and at least one of the other moons that are heading in the opposite direction.

These building blocks of planets can provide a window into the early years of the solar system.

The astronomers were looking for objects on the fringes of the solar system when they spotted the Jupiter moons.

Why are we just now hearing about it? "It probably has collided with them over time", Sheppard said.

Telescopes in Chile, Hawaii and Arizona were used for the original discovery and year-long confirmation of the moons. "It took a year to figure out what these objects were".

Another two moons rest in an inner section of moons that orbit in prograde. Those 2017 moons were labeled S/2016 J1 and S/2017 J1.

Astronomers suspect that the retrograde moons may be the remains of larger moons that were destroyed in head-on collisions with prograde objects. The main theory on the origin of these moons is that were of larger moons of ancient plants that were broken apart during some ancient cosmological event, most likely due to collisions with comets or asteroids.

And then there's the oddball moon.


Nine of the new moons are found among outer concentrations of moons orbiting Jupiter in retrograde - in the opposite direction of the gas giant's axis rotation. Sheppard's girlfriend came up with a name for it: Valetudo, the great-granddaughter of the Roman god Jupiter.

"Our other discovery is a real oddball and has an orbit like no other known Jovian moon", Sheppard explained.

Using the team's observations, Gareth Williams at the International Astronomical Union's Minor Planet Center was able to measure out the orbits for these newly found moons each about one to three kilometres in size. While nine of the other moons orbit in the opposite direction, farther out in the retrograde group.

This is an unstable situation. "Head-on collisions would quickly break apart and grind the objects down to dust."Some of Jupiter's moons and moon groupings, including the "oddball", could have formed from collisions like this, according to the statement".

Scott Sheppard: "So it's basically going down the highway in the opposite direction, so it's like going against traffic". What's truly freakish is that this set up prone to four moon-to-moon collisions. The moons are so faint that they are not actually visible on any single exposure, only when several images are combined. Maybe we need something similar for tiny moons. "We know nothing, really, more than that".

That brings the total number of moons around the gas giant to 79.

Scientists believe moons like Valetudo and its siblings appeared soon after Jupiter formed.

Famed astronomer Galileo Galilei discovered the first four moons of Jupiter way back in the early 1600s. It's just very hard to follow those. The orbits of 9 other small Jovian moons are yet unknown. But its total lunar eclipse is more than ever before than any other planets including Saturdays, whose 62 endorsement has runner-up.

Jupiter's largest moon, Ganymede, is the ninth-largest object in the solar system, bigger than the planet Mercury and dwarf planets like Pluto.

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