It’s about 13.7 billion km (8.5 billion miles) from the Sun. 2014 UZ224 measures about 530 km (330 miles) in diameter and takes around 1,100 Earth years to complete its orbit. Its diameter means it’s under the 400km limit that would be needed to make it spherical, assuming it’s made mostly of ice (as many dwarf planets are). The International Astronomical Union (IAU) is still debating its status as a dwarf planet, but they have already included it in its Minor Planet Center’s list, joining a list of others which include Eris, Haumea, Makemake, Ceres, and Pluto.
2014 UZ224 was found using an instrument that sounds like it’s from a cheesy sci-fi movie: the Dark Energy Camera (DECam). This camera was built to observe stellar and galactic phenomena as they move away from Earth (as “dark energy” is what powers the universe’s continuing expansion).
Using images from the DECam, a project called the Dark Energy Survey (DES) is creating a map of the universe to help study dark energy. It was through these DES maps that students of University of Michigan astronomy professor David Gardes picked out 2014 UZ224 from the background noise about two years ago. Gardes believes that their DES maps, plus the software his students developed to analyze data from them, may help reveal the elusive Planet Nine — a potential planet the size of Neptune.
“I’m excited about our chances of finding it,” Gardes told NPR.
Our ability to see out into space continues to improve, so it’s not surprising that we keep finding these lost celestial objects lurking in the galaxy. The James Webb Space Telescope (JWST) scheduled to launch in 2018 and the Advanced Technology Large-Aperture Space Telescope (ATLAST) is planned for some time between 2025 to 2035, by which time our imaging technology should be indistinguishable from magic.
There’s a ninth planet out there somewhere, about the size of Neptune, but so far out that we haven’t found it, partly due to its orbital path being predicted as not on the plane of the ecliptic. But it won’t be long now. If Planet Nine is out there, we’ll find it.