MOONS OVER JUPITER: Astronomers confirm planet has 79 - 18 more than Saturn

MOONS OVER JUPITER: Astronomers confirm planet has 79 - 18 more than Saturn

JOE PALCA, BYLINE: Several times a year, Scott Sheppard heads to telescopes around the world to search for distant objects in our solar system.

This discovery of the small moons brings Jupiter's total to 79.

Jupiter's tally of moons just got a little bit larger. The moon, tentatively named Valetudo, also has a more inclined orbit than other prograde moons and is one of the smallest moons of Jupiter discovered to date, measuring less than 1 kilometer in diameter.

It's easy to understand why these 12 new additions had been missed so far.

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.

Just when we thought we had a pretty solid understanding of the celestial objects within our very own solar system, astronomers made a stunning discovery of a dozen new moons orbiting the massive planet of Jupiter. The orbits of the new moons are marked with thicker curves.

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's southern hemisphere is pictured by NASA's Juno spacecraft on the outbound leg of a close flyby of the gas-giant planet in an image released on July 2, 2018. These moons include the famous Galileans: Io, Europa, Ganymede, and Callisto.

The twelfth moon has already earned a proposed name, despite being only about two-thirds of a mile in diameter.

Elucidating the complex influences that shaped a moon's orbital history can teach scientists about our Solar System's early years. The new ones were found because technology has gotten better and better over the years.

The moons were discovered a year ago, but the IAU typically requires a year of calculations to confirm the existence of newly discovered moons.

The last of the team's discoveries is the strangest of them all.

One of the newly discovered moons is an "oddball", Sheppard said. They rotate retrograde, that is, not in the direction of rotation of Jupiter, and in the opposite direction. It orbits in an opposite direction from the other moons near it, meaning head-on collisions are much more likely to occur. This means, unlike the closer in moons, it crosses the outer retrograde moons. They also are thought to be the result of an earlier collision and take about a year to complete one orbit.

When Galileo first peered through his telescope at Jupiter in 1610, he was shocked to see that the planet was not alone-it was orbited by four moons, a fact that upended then-current theories of astronomy. "Head-on collisions would quickly break apart and grind the objects down to dust".

Valetudo's idiosyncratic path increases the likelihood that it will one day stray into the path of another moon and collide with it. So they were likely formed after they had dissipated.

Overall, this was a tough, but very rewarding discovery. That makes it a powerful tool for surveying the night sky in search of faint objects. They are about one to two kilometres across, said astronomer Gareth Williams of the International Astronomical Union's Minor Planet Centre.

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