Bright spot on dwarf planet may be portal to its interior

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI/LPI

Bright spot on dwarf planet may be portal to its interior

The mysterious bright spot on the dwarf planet Ceres has been revealed in its highest resolution yet, and the bright materials in it appear to be coming from a fractured dome—a possible portal to icy materials in the subsurface. Last year, NASA’s Dawn spacecraft arrived in orbit around Ceres, the asteroid belt’s largest object and one that is suspected to harbor ice in its interior. Almost immediately, scientists began speculating about the bright spot in the middle of 90-kilometer-wide Occator crater, which at 80 million years old is geologically fresh. In December 2015, the Dawn team reported a haze of water vapor above the crater—a cloud that grew as temperatures rose during the day, and disappeared at night as temperatures dropped and the water vapor condensed into frost. They also found evidence that the bright material on the surface was most likely a residue of mineral salts. Dawn has since moved to a closer orbit around Ceres and has now revealed the bright spot at 35 meters per pixel. At the center of Occator is a 9-kilometer-wide pit, and in the center of that is an uplifted dome, 2 kilometers wide and full of ringlike fractures (pictured here). Heat from the impact that made Occator probably allowed a mixture of ice, salts, and rock in Ceres’s interior to become more fluid and rise up to the surface, scientists reported today at the Lunar and Planetary Science Conference in The Woodlands, Texas. But they said that one remaining mystery is why the bright materials are still so pristine today. The youthfulness of the materials—likely younger than 80 million years—suggests that fresh ices and salts could have come up from Ceres’s interior long after the impact.

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