New images of the dwarf planet Ceres, the largest body in the asteroid belt, reveal a world that's even stranger than scientists expected.
The 590-mile-wide (950 kilometers) icy world is pockmarked by craters, photos released Tuesday show, and has curiously rugged terrain at its south pole and several enigmatic bright spots dotting its surface.
It's those bright spots—perhaps expanses of ice, but for now scientists can't say—that are attracting the bulk of speculation. At least one of them has been glimpsed before in blurrier pictures taken with the Hubble Space Telescope.
"Our sharper view reveals some [spots] that Hubble could not discern," says Dawn chief engineer and mission director Marc Rayman of NASA's Jet Propulsion Laboratory. "As Dawn gets closer and gathers more data on their appearance and their composition, we surely will get insight into what they are. I can't wait!"
Shot February 12, the latest images were taken when the Dawn spacecraft was 53,500 miles (86,000 kilometers) from Ceres. Dawn is scheduled to slip into orbit around Ceres on March 6 and spend the next year looking for clues about what the world is made of, what lies beneath its surface, and the unexpected tufts of water vapor reported in 2014.
Why It Matters
Watery and relatively huge, Ceres is wildly out of place in the asteroid belt, a stretch of space between Mars and Jupiter that's mostly populated by smaller, dustier space rocks.
Some scientists think that's because Ceres was born somewhere else, while others suggest it might have grown up at a slightly different time. Dawn will help unravel the mystery of Ceres by comparing it with another relative giant in the asteroid belt: dry and dusty Vesta, which Dawn orbited from mid-2011 through late 2012.
The Big Picture
Ceres and its neighbors are relics from the dawn of the solar system, when the sun was young and the planets grew from a swirling disk of gas and dust. Reading the ancient records stored in bodies like Ceres helps reconstruct those early years.
These worlds contain clues not only about the solar system's birth 4.5 billion years ago, but also about a tumultuous reorganization that took place hundreds of millions of years later.
The Dawn spacecraft will spend the next year studying Ceres, and when it runs out of fuel, it'll shut down and stay in orbit around the dwarf planet.