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Astronomers Serendipitously Discover 12 Moons Around Jupiter

Astronomers Serendipitously Discover 12 Moons Around Jupiter

They first spotted the 12 new moons in the spring of 2017, but they had to conduct several more observations before they could confirm that the moons actually orbited Jupiter, according to Gareth Williams of the International Astronomical Union's Minor Planet Center.

"Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant Solar System objects", Sheppard said.

In March 2017, Jupiter was in the ideal location to be observed using the Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile, which has the Dark Energy Camera and can survey the sky for faint objects.

The team of astronomers originally wasn't even looking for the 12 new moons.

Jupiter's moon Valetudo (pointed out with orange bars) moves relative to background stars in these images taken with the Magellan Telescopes at the Las Campanas Observatory. Valetudo orbits Jupiter in the same direction that the planet spins, but a bunch of other small moons share the same orbital path while travelling in the opposite direction. Some slipped in and out of view, complicating the task. Because the planet is so big and bright, researchers surmised that unrecorded moons could be faint, or even obscured, or quite far from the gas giant. These moons include the famous Galileans: Io, Europa, Ganymede, and Callisto.

Two of the new discoveries are part of a closer, inner group of moons that orbit in the prograde, or same direction as the planet's rotation. One moon is located in the outer group but orbits in the opposite direction.

Researchers announced Monday that they'd discovered a dozen new moons around Jupiter, including a tiny one that they're calling an "oddball".

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Is there life beyond Earth? By contrast, retrograde moons were probably objects that once were wandering around the solar system and got snared by Jupiter's gravity.

Before Sheppard's team conducted their survey, there were 69 known Jovian moons, but there's always been reason to believe there are quite a few more. Sheppard's team speculates Valetudo could be a remnant of a collision between one or more moons.

"This is an unstable situation", Sheppard said.

Due to their sizes-one to three kilometers-these moons are more influenced by surrounding gas and dust. Astronomer Scott Sheppard of the Carnegie Institution for Science is on the hunt for Planet Nine, a hypothetical planet many astronomers think should exist in the distant reaches of our Solar System, beyond Pluto.

All the newly identified moons are relatively small, ranging in size from about six-tenths of a 1km to 4km. The "oddball" with the proposed name Valetudo orbits in the prograde, but crosses the orbits of the planet's outer retrograde moons.

This was at a time when the Sun was still surrounded by a rotating disc of gas and dust from which the planets were born. In fact, of Jupiter's 67 previously discovered moons, the 33 outermost moons all have retrograde orbits. "Cars are coming right at you, and it's very likely you're going to have some head-on collision". Sheppard added that his team performed similar moon searches at Uranus and Neptune - but came up empty.

The newly discovered moons await naming, a task for which the public may be enlisted, so it's a good idea to brush up on the IAU's naming rules for Jovian moons - and which names have already been taken.