If you’re like us, you’ve been following the story of the bright spots on Ceres in great detail, from their initial discovery to the seemingly conclusive evidence they were made of salt to the recent study suggesting they mysteriously brighten occasionally.
Now, at the 47th annual Lunar and Planetary Science Conference in Texas this week, scientists have unveiled stunning new images of the bright spots, taken by the Dawn spacecraft in its current and lowest orbit around the dwarf planet, just 385 kilometers (240 miles) above the surface. That’s lower than the International Space Station (ISS) is above Earth.
The latest images reveal a slew of features, but perhaps the most interesting is Occator Crater. This is the location of the brightest spots on the surface of Ceres, thought to be mostly composed of magnesium sulfate. At first thought to be just one spot, Occator was later revealed to have multiple spots – and the new images (above and below) show them in glorious detail.
A close-up of the Occator Crater. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI
"Before Dawn began its intensive observations of Ceres last year, Occator Crater looked to be one large bright area,” said Ralf Jaumann, planetary scientist and Dawn co-investigator at the German Aerospace Center (DLR) in Berlin, in a statement. “Now, with the latest close views, we can see complex features that provide new mysteries to investigate.”
Truth be told, aside from the spots, Ceres isn’t the most fascinating world – it certainly pales in comparison to the surprisingly feature-rich Pluto. But it does have its quirks; aside from Occator, there are hundreds of other bright spots on the surface, in addition to a large unexplained mountain called Ahuna Mons.
The formation of the spots is still a bit of a mystery, but recent evidence suggests they may in part be fueled by subsurface water or ice leaking to the surface. In fact, scientists think Ceres may once have played host to a vast subsurface ocean early in the Solar System when it was hotter, not too dissimilar to that on Europa and Enceladus today, providing much of the material for the bright spots. The dwarf planet may also still be somewhat geologically active.
Scientists will examine interesting features like Occator in much more detail, with Dawn in its lowest orbit, to help unravel the remaining secrets of Ceres.
“Now that we can see Ceres’ enigmatic bright spots, surface minerals and morphology in high resolution, we're busy working to figure out what processes shaped this unique dwarf planet,” said Carol Raymond, deputy principal investigator for the Dawn mission, based at NASA's Jet Propulsion Laboratory, Pasadena, California, in the statement.
The map above shows the surface of Ceres in enhanced color. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA