Scientists discover 10 never-before-seen moons orbiting Jupiter, and one's an oddball
Jupiter is a huge planet with a ridiculous number of moons.
And now, thanks to new research, that number just became even more ridiculous.
Scientists have discovered 10 never-before-seen moons of Jupiter in 2017 and confirmed two others that had already been seen, bringing the total number of known moons circling the gas giant planet to 79, more than any other planet in the solar system.
How exactly did these moons evade detection for so long? Well, it's not as if they're large and bright like some of Jupiter's other moons, for instance, Europa or Ganymede.
These are tiny moons that are likely obscured by gas and dust. It took about a year to confirm their existences and their orbits, which is why we haven't heard about them until now.
Nine of the moons are considered retrograde, which means they orbit in the opposite direction of Jupiter's spin, according to the researchers.
Two of the moons orbit in the same direction as Jupiter's rotation, and they have a surprising backstory. Both of them, say scientists, are likely pieces of another, larger moon that broke apart at some point in the planet's past.
And the last moon is a weird one.
"Our other discovery is a real oddball and has an orbit like no other known Jovian moon," Scott Sheppard, Carnegie scientist and leader of the team behind the discovery, said in a statement.
"It's also likely Jupiter's smallest known moon, being less than one kilometer in diameter."
Take note of this tiny moon, because it may not have much time left.
The "oddball" takes about a year and a half to orbit Jupiter, a course that brings it through the path of the retrograde moons, making collisions more likely.
"This is an unstable situation," said Sheppard. "Head-on collisions would quickly break apart and grind the objects down to dust."
The oddball moon might even be the final remaining piece of a moon that researchers are calling Valetudo, the name of Jupiter's granddaughter in Roman mythology.
The most amazing thing about all of this is that the discovery of these newfound moons was made by happy accident.
The researchers behind the new work were actually on the hunt for Planet X (sometimes known as Planet 9), the theoretical — and as yet undiscovered — large planet out beyond Pluto's orbit.
While they didn't find hard evidence for it, they did find these new Jovian moons.
"Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant solar system objects," Sheppard said.
"So we were serendipitously able to look for new moons around Jupiter while at the same time looking for planets at the fringes of our solar system."
Scientists still aren't sure if Planet X exists, but the hunt continues. Who knows what they'll find next.
Miriam Kramer worked as a staff writer for Space.com for about 2.5 years before joining Mashable to cover all things outer space. She took a ride in weightlessness on a zero-gravity flight and watched rockets launch to space from places around the United States. Miriam received her Master's degree in science, health and environmental reporting from New York University in 2012, and she originally hails from Knoxville, Tennessee. Follow Miriam on Twitter at @mirikramer.
