The more information that comes back from the Dawn probe currently orbiting Ceres, the 500 mile in diameter dwarf planet in the Asteroid Belt, the stranger the place looks. The latest discovery is that of a three mile high pyramid shaped mountain, towering above an otherwise flat region of the icy world. Dawn is now returning information from its second mapping orbit, 2700 miles above Ceres, and new discoveries are coming thick and fast.
“For example,” says JPL’s Carol Raymond, deputy principal investigator for the Dawn Mission, “Icy moons in the outer solar system have craters with central pits, but on Ceres central pits in large craters are much more common. These and other features will allow us to understand the inner structure of Ceres that we cannot sense directly.”
While the newly discovered peak is impressively tall, it’s still not as tall as Mount Everest, which is roughly 5.4 miles high. Nor is the mountain on Ceres anywhere near the tallest mountain off Earth. That honor goes to Olympus Mons, a shield volcano on Mars that towers 16 miles above the surface of that planet.
Oh, and those bright white glowing spots that look like city lights in the center of that crater? More mysterious than ever. As the Dawn spacecraft’s orbit tightens up, we can see more and more detail in those spots. The main one looks like it’s roughly six miles across, and there are many more smaller ones in the cluster near it than we had seen before. This is looking more and more like ejecta from the impact that formed the crater in the first place, given that the brightest spot is in the exact center, but ejecta comprised of what? Until Dawn gets closer – its third mapping orbit won’t be established until August, where it closes to within about 900 miles of the surface – we may not be able to get good enough spectral analysis of the bright areas to find out. Chances are pretty good that it’s not actually a spaceport – still, it’s fun to think about.
Ceres is peppered with other craters of varying sizes, many of which have central peaks. There have been other geological forces at work as well, including flows, landslides and collapsed structures. Ceres has been a bit more geologically active than the protoplanet Vesta, which Dawn studied intensively for 14 months in 2011 and 2012.
Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct targets in our solar system. It arrived at Ceres, the largest object in the main asteroid belt between Mars and Jupiter, on March 6, 2015. Dawn will remain in its current altitude until June 30, continuing to take images and spectra of Ceres in orbits of about three days each.
Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.
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