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posted by on Tuesday February 07 2017, @02:02AM   Printer-friendly
from the perfect-vacation-spot dept.

Scientists theorize that Ceres's cryovolcanoes slowly flatten over time:

A recently discovered solitary ice volcano on the dwarf planet Ceres may have some hidden older siblings, say scientists who have tested a likely way such mountains of icy rock – called cryovolcanoes – might disappear over millions of years. NASA's Dawn spacecraft discovered Ceres's 4-kilometer (2.5-mile) tall Ahuna Mons cryovolcano in 2015. Other icy worlds in our solar system, like Pluto, Europa, Triton, Charon and Titan, may also have cryovolcanoes, but Ahuna Mons is conspicuously alone on Ceres. The dwarf planet, with an orbit between Mars and Jupiter, also lies far closer to the sun than other planetary bodies where cryovolcanoes have been found.

Now, scientists show there may have been cryovolcanoes other than Ahuna Mons on Ceres millions or billions of years ago, but these cryovolcanoes may have flattened out over time and become indistinguishable from the planet's surface. They report their findings in a new paper accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

[...] Ceres has no atmosphere, so the processes that wear down volcanoes on Earth – wind, rain and ice – aren't possible on the dwarf planet. Sori and his colleagues hypothesized that another process, called viscous relaxation, could be at work. Viscous relaxation is the idea that just about any solid will flow, given enough time. For example, a cold block of honey appears to be solid. But if given enough time, the block will flatten out until there is no sign left of the original block structure. On Earth, viscous relaxation is what makes glaciers flow, Sori explained. The process doesn't affect volcanoes on Earth because they are made of rock, but Ceres's volcanoes contain ice – making viscous relaxation possible. On Ceres, viscous relaxation could be causing older cryovolcanoes to flatten out over millions of years so they are hard to discern. Ceres's location close to the sun could make the process more pronounced, Sori said.

The vanishing cryovolcanoes of Ceres (open, DOI: 10.1002/2016GL072319) (DX)


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  • (Score: 1) by DmT on Tuesday February 07 2017, @11:53AM

    by DmT (6439) on Tuesday February 07 2017, @11:53AM (#463979)

    For any sufficiently advanced space faring race, it should really not be problematic to find some ice and water in space. Therefor a water crisis is not realistic and also attacking earth to steal water does not make any sense really.

    • (Score: 3, Interesting) by takyon on Wednesday February 08 2017, @12:37PM

      by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Wednesday February 08 2017, @12:37PM (#464510) Journal

      Ceres' oblateness is consistent with a differentiated body, a rocky core overlain with an icy mantle. This 100-kilometer-thick mantle (23%–28% of Ceres by mass; 50% by volume) contains up to 200 million cubic kilometers of water, which would be more than the amount of fresh water on Earth. This result is supported by the observations made by the Keck telescope in 2002 and by evolutionary modeling. Also, some characteristics of its surface and history (such as its distance from the Sun, which weakened solar radiation enough to allow some fairly low-freezing-point components to be incorporated during its formation), point to the presence of volatile materials in the interior of Ceres. It has been suggested that a remnant layer of liquid water may have survived to the present under a layer of ice.

      It really goes to show how little water there is on Earth in comparison to tiny icy-rock objects like Ceres, Rhea, Pluto, etc. Ceres has around 1.28% of the Moon's mass, but a similar amount of fresh water/ice to the Earth.

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      • (Score: 0) by Anonymous Coward on Wednesday February 08 2017, @07:20PM

        by Anonymous Coward on Wednesday February 08 2017, @07:20PM (#464692)

        The key there is "fresh water on earth", not "all water on earth". Earth has a tiny amount of Fresh Water and a fuckton of Salt Water.