As sure as the Sun rises in the east, NASA’s Dawn spacecraft continues to orbit ever closer to the dwarf planet Ceres. It’s now in its second orbit, just 2,700 miles from the surface. As such, it’s given scientists the sharpest, highest-resolution images of Ceres to date. Despite the quality images, scientists still have no idea as to how to identify Ceres’ mysterious bright spots, which have vexed professional and amateur astronomers alike since their discovery. Are they ice? Salt? Alien graffiti? At this rate, we may never know!
“The bright spots in this configuration make Ceres unique from anything we’ve seen before in the solar system. The science team is working to understand their source. Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt. With closer views from the new orbit and multiple view angles, we soon will be better able to determine the nature of this enigmatic phenomenon,” said Chris Russell, principal investigator for the Dawn mission based at the University of California, Los Angeles.
Soon? How soon? “Sometime before the heat-death of the universe” doesn’t count as soon, at least not for most of us.
The spots Russel is referring to are located in a crater about 55 miles across, where they’re loosely clustered around one large spot in the center. NASA isn’t just interested in Ceres’ bright spots; the pockmarked surface shows evidence of liquid flows, landslides and ruined structures that all point to a more active past for the craggy dwarf planet.
Dawn will remain at this altitude until June 28, at which point it will move to its next orbit. This third pass will take it within 900 miles of Ceres’ surface, where scientists will no doubt continue to be baffled by the white splotches on its surface.