The rocky world called Ceres never grew large enough to join the select club of full-grown planets, settling instead for the rank of dwarf planet. But Ceres may have an even better claim to fame: cold volcanoes spouting ice and mud.
New observations by NASA’s Dawn spacecraft suggest that Ceres, which orbits between Mars and Jupiter, boasts so-called cryovolcanoes at the bottom of several of its craters. Other new findings confirm that Ceres is laden with ice, which lurks in the soil below the surface and even builds up in crater bottoms. The findings were presented Thursday at a meeting of the American Geophysical Union.
“The members of the (Dawn science) team expected a lot of things, but not what we finally got,” says Ralf Jaumann of the German Aerospace Center. “I was completely surprised, and ‘completely’ means ‘completely.’ ”
As the biggest resident of the asteroid belt beyond Mars, Ceres has drawn the gaze of the Hubble Space Telescope and other instruments based near Earth. But it had never gotten a visit from a spacecraft until Dawn pulled up in 2015 and trained a battery of high-powered sensors on its surface.
Dawn’s cameras revealed that the floors of several craters on Ceres are coated with flowing material akin to lava on Earth. But the material looks less viscous than similar formations elsewhere in the solar system, Jaumann says, and it is tinged slightly blue – the same color as a mountain on Ceres thought to have formed by eruptions of ice mixed with mud.
Jaumann and his colleagues theorize that the flowing material is a mixture of ice, mud and salts that erupted out of weak points in Ceres’ surface when large space rocks or other objects bombarded the dwarf planet. He and his team will publish their results in an upcoming issue of Geophysical Research Letters.
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SOURCE: USA Today, Traci Watson