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Origin of ice on the Moon may be explained by this dwarf planet's 'darkest secret'

Amid news from NASA’s Juno and New Horizons missions, fresh interest has emerged in the Dawn mission to Ceres, following the discovery of craters that contain the dwarf planet’s “darkest secret,” according to Norbert Schorghofer, a Dawn guest investigator at the University of Hawaii at Manoa and lead author of a study published last week in the journal Geophysical Research Letters. Research shows parts of these craters are cast in permanent shadow and create cold traps that can collect ice deposits for billions of years.

“Ceres is an ice-rich body to begin with,” Schorghofer told Digital Trends. “The extra ice is significant because it may have the same origin as the ice on Earth’s Moon.”

Schorghofer and his team reconstructed the topography of Ceres’s northern hemisphere using stereo images taken by the Dawn spacecraft, which depicted craters and plains along the dwarf planet’s surface. They ran this terrain through a computer model to map how the shadows moved over a year, and to identify which regions received indirect sunlight. The simulation revealed dozens of large, permanently shadowed areas totaling 695 square miles. The researchers’ next step is to figure out what’s in these craters, Schorghofer said.

Ceres lies in an asteroid belt between the orbits of Mars and Jupiter, a distance from the Sun that makes the shadowed regions much colder than those found on the moon. Even so, the dwarf planet’s cold traps may hint at the origin of ice on the Moon. “On the Moon and Mercury, only the permanently shadowed regions very close to the poles get cold enough for ice to be stable on the surface,” Erwan Mazarico, a Dawn guest investigator at Goddard, said in a NASA press release.

This study comes less than a week after NASA announced that Dawn would remain at Ceres for long-term monitoring, as the dwarf planet nears the part of its orbit that’s nearest to the Sun.

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