What is a quasi-moon? Is it a moon? Is it an asteroid?
Like a lot of people, Clayton Chilcutt had never heard of this kind of space rock before the introductory astronomy course he took last year at the University of Georgia. But after winning a worldwide contest that he entered for one extra credit point, the sophomore finance major can now brag on his resume that he named one of the few quasi-moons near Earth.
“It’s something that started out so small and, you know, almost meaningless — just extra credit,” said Chilcutt, a 19-year-old from Douglasville. “And it ended up being a contribution to science.”
Credit: Canadian Astronomy Data Centre
Credit: Canadian Astronomy Data Centre
Thanks to Chilcutt, the quasi-moon once known as the jumble of numbers and letters (164207) 2004 GU9 is now immortalized as Cardea.
A quasi-moon is a large asteroid that orbits a star alongside planets and can often appear to be orbiting its neighboring planets, too, in what’s called a quasi-satellite motion. Earth has seven known quasi-moons.
Discovered in 2004, this quasi-moon shares a similar orbital path to Earth around the sun and is expected to stick around until the year 2600. Sometimes, it gets close enough to be drawn in by the Earth’s gravity and can go around our planet on its path but doesn’t actually orbit.
It’s “not a moon, but also not not a moon,” according to Radiolab, the science journalism podcast that launched the naming contest in May with support from the International Astronomical Union.
“Weirdly, if you watch it from the planet, it looks like it’s going around you the way a moon would. But it’s too small and too far away to be a moon,” Radiolab’s website says. “And it’s barely being pulled around by the planet’s gravity. So it’s just hanging out, doing this funny awkward cosmic dance with the planet.”
Credit: HORIZONS System, JPL, NASA
Credit: HORIZONS System, JPL, NASA
Over 10,000 people voted for the name Cardea in December, making Chilcutt the winner out of seven finalists, which also included another UGA student from his same class. The final names were chosen out of 2,700 entries by a star-studded panel that included Bill Nye “The Science Guy,” astrophysicist Wanda Diaz Merced, and actors Penn Badgely and Celia Rose Gooding, among others.
Chilcutt chose the name Cardea after the Roman goddess of doorways and transitions, a guardian of thresholds. He said to him, it sounded celestial.
“Cardea is the divine protector of entrances and transitions. She symbolizes change, guardianship and the passage between realms. This name reflects the quasi-moon’s unique orbital path, embodying a celestial gateway between Earth and space,” his contest submission says.
Chilcutt’s interest in astronomy wasn’t driven by a desire to pursue a science degree. He’s studying finance, after all.
“I watched ‘Interstellar,’ and it’s a good movie,” he said. “I thought it’d be cool to take astronomy.”
But now, after naming a “weird” space rock, he’s glad he took the class and recommends other students do, too.
“They make science classes really hard, you know, like biology or chemistry,” Chilcutt said. “Take an astronomy course. It’s actually fun and interesting.”
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