Ever since the Dawn spacecraft encountered the dwarf planet Ceres, scientists have wondered what those strange bright spots are.
According to BBC News, a team of researchers explained the mysterious bright spots as areas of the surface where impacts exposed salt water beneath.
"We reviewed three possible analogs for the bright spots (ice, clays and salts)," study co-author Lucille Le Corre, a research scientist at the Planetary Science Institute, said in a news release. "Salts seem to fit the bill and are the best possible explanation of what we see on the surface of Ceres."
For their study, published in the journal Nature, the researchers examined images from Dawn's camera tool and noticed the water-ice exposed by the impacts were rich in salt.
"The location of some bright spots also coincide with places where water vapor was detected by other spacecraft," study co-author Vishnu Reddy, a PSI research scientist, said in the release. "This gives us confidence that the bright spots are likely salt deposits left over by sublimating salty water."
The researchers expect the bright spots will eventually fade when the ice is no longer fresh.
"It's a bit like a comet, but you need to understand that Ceres is a partially differentiated body. So, it has a shell structure," study lead author Andreas Nathues, the camera's principal investigator and a scientist at the Max Planck Institute for Solar System Research, told BBC News. "There is very likely an ice shell below the crust. And this is completely different from comets. Comets are primitive objects, having original material that is only very, very slightly changed."
