Astronomers just discovered 12 new moons around Jupiter

Our solar system is already teaming with nearly 200 moons, and we just got 12 more to add to the list. A team led by astronomer Scott Sheppard out of the Carnegie Institution for Science discovered the moons in 2017 using one of the most powerful digital cameras in the world, the Dark Energy Camera. And after follow-up observations, they’ve confirmed that Jupiter has even more moons than we thought. And these new moons point to a violent and destructive past. Following is a transcript of the video.

There are nearly 200 moons in our solar system. And more than a third of those belong to a single planet: Jupiter. Jupiter has the most moons of any other planet. And if that’s not enough astronomers recently discovered 12 new ones to add to the list.

Scott Sheppard: “Jupiter now has 79 known moons in the solar system.”

That’s Scott Sheppard. He’s an astronomer at the Carnegie Institution for Science who spends his time searching for new objects in our solar system. Already, he and his team have discovered evidence of a potential planet beyond Pluto called Planet Nine. And now, 12 new moons of Jupiter including the weirdest one yet.

Scott Sheppard: “We believe these objects were probably captured by Jupiter a long time ago and they are grouped in their orbits.”

Jupiter’s moons are sort of like opposite lanes on a highway. Two of the new moons are in a group that orbit in the same direction as Jupiter’s rotation called the prograde group. While nine of the other moons orbit in the opposite direction, farther out in the retrograde group.

And each moon stays in its respective lane. Except for the last moon. It’s a rebel. It orbits in the same direction as Jupiter’s spin, similar to the first two new moons. But it’s not part of the same group. Instead, its path takes it into the realm of the nine moons that orbit in the opposite direction.  

Scott Sheppard: “So it’s basically going down the highway in the opposite direction, so it’s like going against traffic. And that makes it a very unstable situation.”

Sheppard suspects that situations like this have happened in the past. Which helps explain why Jupiter has so many moons in the first place. Its powerful gravitational pull allows it to capture large passing objects that then collide with each other, forming dozens of new, smaller moons.

Scott Sheppard: “It’s been about a decade since the last moons around Jupiter were discovered. The new ones were found because technology has gotten better and better over the years. We’re using the most advanced digital cameras in the world … And we’re going a little deeper than in the past as well. So that’s why we’re able to find these new moons.”

The moons are too small to see with the average telescope — measuring only a few kilometers in size. It took one of the most powerful digital cameras in the world — the Dark Energy Camera — to spot them. Now, all that’s left is to name the new moons.

Sheppard and his team already proposed a name for the rebel moon. “Valetudo” — after the great-granddaughter of the Roman god Jupiter — also known as the goddess of health and hygiene. For the other 11 moons, Sheppard said they might let the public help out. 

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from SAI