Mystery of Ceres’ weird bright spots solved! (Maybe)

NASA has been examining the images Ceres from the spacecraft Dawn since May in order to figure out just what in the heck was causing the dwarf planet’s mysterious bright spots. In June, the scientists discovered that Ceres had even more spots than they had seen before, and were still puzzled as to what caused the reflection.

Now, NASA finally has an answer, which they announced at the European Planetary Science Congress in Nantes, France.

It’s a bird, it’s a plane, it’s—

“We believe this is a huge salt deposit,” Dawn’s principal investigator Chris Russell told a crowd of scientists Monday at the Congress, as reported by CNET. “We know it’s not ice and we’re pretty sure it’s salt, but we don’t know exactly what salt at the present time.”

Wait. What?

Up until this point, the leading theory was that the bright spots were the result of sunlight reflecting off of ice. Even the principal investigator of the Dawn mission, Chris Russell, considered this likely enough to mention. “Dawn scientists can now conclude that the intense brightness of these spots is due to the reflection of sunlight by highly reflective material on the surface, possibly ice,” he had said in May.

This notion was strengthened by the fact that Ceres is believed to contain an ocean under its surface. Asteroid collisions could have easily exposed the ocean on the surface of the planet.

However, thanks to visible and infrared mapping spectrometry of the reflections, the scientists were able discern that the spots weren’t made of ice, but most likely salt. Moreover, the salt seems to be indigenous to the dwarf planet—no asteroids involved there, either.

“[Salt] tells me that this is an active surface,” Russel said. “Some comet or asteroid did not come in carrying salt, this is derived from the interior somehow.”

Salt also seems to be responsible for the streaks on Ceres’ weird lonely mountain. How the mountain got there, NASA has no idea—so they’ve just turned to the public for help with ideas. NASA also isn’t sure how the salt got from the interior of the planet to the surface, as the surface seems to be entirely dry—so they probably would take advice on that, too.

Watch the full talk below!

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Feature Image: NASA