Say Hello to Our Solar System’s Newest Dwarf Planet

Spotting the dwarf planet could help in the search for Planet Nine

The new dwarf planet—too small to join the ranks of our solar system's eight planets—orbits the sun roughly twice as far away as Pluto. Adventure_Photo via iStock

Planetary scientists may spend much of their time peering at distant solar systems in search of new planets, but sometimes surprising discoveries pop up in our own cosmic backyard. Just this week, a group of astronomers announced that they have discovered a brand new dwarf planet orbiting the distant edges of our solar system.

Called 2014 UZ224, this dwarf planet is pretty tiny cosmically speaking. At about 330 miles across, it’s roughly half the size of Pluto but orbits our sun twice as far away, well outside the ring of asteroids and debris known as the Kuiper Belt, Joe Palca reports for NPR. At about 8.5 billion miles from the sun, it takes about 1,100 Earth years to make a single orbit.

The new dwarf planet was first spotted a few years ago in images taken by an instrument called the Dark Energy Camera, but at the time, researchers didn't know what they had. The camera, developed by University of Michigan researcher David Gerdes, was originally intended to take pictures of distant galaxies to map out part of the cosmos, Palca reports.

But when Gerdes tasked a group of undergraduates with finding solar system objects hiding in this map, things got interesting.

Objects like stars and galaxies are so far away that from here on Earth they look as if they’re not moving. So to look for objects spinning through our cosmic backyard, the students had to keep an eye out for movement, Sarah Kaplan reports for The Washington Post. But because the images the Dark Energy Camera captured weren’t taken at regular intervals, Gerdes’ students couldn’t just page through them like a flipbook.

"We often just have a single observation of the thing, on one night," Gerdes tells Palca. "And then two weeks later one observation, and then five nights later another observation, and four months later another observation. So the connecting-the-dots problem is much more challenging."

To pick moving objects out against a backdrop of distant galaxies, the students developed a computer program that would analyze the images and pick out objects moving about our solar system. It worked: over the course of the summer, these undergraduates managed to identify six previously unknown objects moving through the camera’s images. But it wasn’t until Gerdes was taking the program for a spin himself last summer that he spotted UZ224, Kaplan reports.

"The fact that we can find a very distant, very slow-moving object like this in our survey is a promising sign that if there's more things like this out there, we have a good shot at finding them,” Gerdes tells Kaplan.

While UZ224 is an exciting discovery, Gerdes has bigger plans in mind: joining the hunt for the long-rumored “Planet Nine.” Earlier this year, astronomers announced that analysis of the movements of several objects floating out past Pluto suggests that there could be a massive planet lurking out at the edge of our solar system, Nola Taylor Redd reports for A tool like Gerdes’ could be a tremendous help to astronomers scanning the skies for signs of this mysterious orbiting object.

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