The nature of the bright spots has yet to be elucidated.
NASA’s Jet Propulsion Laboratory has set up a website at which members of the public can register their votes as to the identify of the strange and unexpected bright spots seen on Ceres by the Dawn probe. Although Dawn will study the spots in much greater detail in the near future, having just assumed its first scientific orbit, in the meantime the nature of spots in anyone’s guess. This author voted for “ice”.
It seems ice is the most popular possibility so far, with 33 percent of the vote. The next most popular choice is “other”, with 28 percent. “Volcano” and “geyser” both have 11 percent, “salt deposit” has nine percent, and “rock” has eight percent.
At about 590 miles in diameter, Ceres is the largest body in the asteroid belt between the orbits of Mars and Jupiter. Dawn had imaged Ceres’s surface throughout its approach. Dawn entered orbit of Ceres on March 6, the first spacecraft to orbit a dwarf planet. From 2011 to 2012, Dawn also orbited the asteroid Vesta, the second-most massive body in the asteroid belt. Having studied both Vesta and Ceres, Dawn is the first spacecraft in history to orbit two extraterrestrial objects. Dawn’s investigations of Vesta and Ceres will shed light on the early evolution of our solar system; both bodies represent incipient planets, gravitationally perturbed early in their formation.
“The approach imaging campaign has completed successfully by giving us a preliminary, tantalizing view of the world Dawn is about to start exploring in detail. It has allowed us to start asking some new and intriguing questions,” said Marc Rayman, Dawn’s mission director and chief engineer at the JPL, in a separate NASA statement.