With 12 new moons, Jupiter reaches 92 and surpasses Saturn – 07/02/2023 – Science

Scientists have discovered 12 more moons orbiting Jupiter in the last week. With the addition, the giant of the solar system takes the lead over Saturn, which led until now with 83 celestial bodies in its orbit.

Satellites are estimated to be small, 1 to 3 kilometers in diameter. They are in the class of irregular moons of Jupiter. That’s because, while the planet and its regular moons — Io, Europa, Ganymede and Callisto — orbit counterclockwise, these celestial bodies go in the opposite direction.

The observation was made by a team of astronomers at the Carnegie Institution, led by Scott Sheppard. They were also responsible for the discovery, in 2019, of 20 moons on Saturn, which “beat” Jupiter.

The 12 moons were observed in 2021 and confirmed in January of this year. According to Fernando Roig, doctor in astronomy at the National Observatory, the process takes longer because it is necessary to confirm its trajectory for the correct classification.

“When you observe an object for the first time, you see a little light moving in the image, but you cannot determine its trajectory well. So, you need to see it at different points to confirm what it is”, he says.

Still, the discovered moons are in a more external orbit in relation to the planet. The hypotheses for its formation are the collision of objects in space or the capture, by the gravitational field of Jupiter, of bodies like the centaurs, small celestial bodies located between the orbits of the gas giant and Neptune.

Isolated, irregular moons should not be of astrophysical interest for exploration, according to Roig. However, a look at them as a group helps to understand where they came from or how they formed.

The moon Europa is on the radar of space agencies. One of the missions is the Europa Clipper, from NASA, the American space agency, which should make close flybys of the satellite, scheduled to launch in 2024.

The Juice spacecraft (Explorer of the Icy Moons of Jupiter), in turn, should study Callisto and Ganymede, in addition to Europe, and should be launched later this year.

Io, on the other hand, is an “explosive” moon, and has intrigued scientists because of the different eruptions that have been taking place. It is to be observed by NASA’s Juno space probe, which has been orbiting Jupiter since 2016 and is expected to fly within a few hundred kilometers of the moon in December.