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NASA Space Science

Jupiter's Moon Io Has a Volcanic Sub-Surface 48

Posted by timothy
from the other-moons-seething-with-envy dept.
gabbo529 writes "NASA scientists have discovered new information on one of Jupiter's moons, indicating it has a molten magma sub-surface (abstract). This discovery, made using data analysis from NASA's Galileo spacecraft, reveals why that particular moon is the most volcanic object known in the solar system. The moon, which is named Io, produces about 100 times more lava each year than all the volcanoes on Earth combined. The global magma ocean about 30 to 50 kilometers (20 to 30 miles) beneath Io's surface explains the moon's activity." Science has a nice graphic, too.
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Jupiter's Moon Io Has a Volcanic Sub-Surface

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  • It's been widely known for a long time that Io is volcanically active. I remember reading about it in a kids' astronomy book in the 1970's.
    • They certainly didn't know that the solid surface is floating in a more-or-less continuous magma lake in the 70's.

         

    • by Wyatt Earp (1029)

      The volcanos were first observed on March 9th 1979 from images taken on March 5th 1979.

      http://en.wikipedia.org/wiki/Linda_A._Morabito [wikipedia.org]
      http://en.wikipedia.org/wiki/Io_(moon)#Pioneer [wikipedia.org]

    • Not unless it was from a really fast publisher. The volcanoes were discovered March 5th, 1979.
      • by mark-t (151149)
        I don't know the publisher... nor the exact date. I do vividly remember the pictures in the book, however. They were colorful artistic renderings rather than photos, and the school I remember being in at the time would place it sometime definitely prior to 1980. If they were only just discovered in '79, then it must have been in '79 that I read that book. I really did not realize that the discovery was that recent at the time. I was just a kid who thought astronomy was cool and I liked the pictures in
    • by Meshach (578918) on Thursday May 12, 2011 @05:44PM (#36112596)

      It's been widely known for a long time that Io is volcanically active. I remember reading about it in a kids' astronomy book in the 1970's.

      People have known for a long time that Io has volcanic activity but no one new before now that Io has a sub-surface made entirely of magma.

      The main theory of how the planet Earth evolved was that the land was formed from a magma sub-surface that cooled and gave us what we have today. Ergo Io may be a window into the Earth's development.

      • by dgatwood (11270)

        Except that it won't ever cool down like Earth did, thanks to extreme tidal heating.

  • by casualsax3 (875131) on Thursday May 12, 2011 @05:38PM (#36112538)

    ...and has been in the planet's atmosphere since 2003.

    That's a really interesting way of looking at it.

  • by gcnaddict (841664) on Thursday May 12, 2011 @05:50PM (#36112652)
    How many Slashdot readers don't know that Io is the most volcanically active body in the solar system?

    I just thought it was kinda frustrating reaching Io at the end of the description. I was hoping it was another of Jupiter's moons because I figured if it were Io, Io would've been stated.
    • by gsslay (807818)

      It was; "The moon, which is named Io". It was just buried halfway through the article and introduced in the most backwards and awkward way possible.

      Perhaps because this was discovered by people who are called scientists and work for the organisation that is named NASA. It could have been explained what these bodies that are called moons are, but there's only so much the person that I call I can take in at what is known as one time.

  • by Anonymous Coward

    "Whether they ever find life there or not, I think Jupiter should be considered an enemy planet." - Jack Handy

  • magma

  • I know all about this moon.

  • Io is the most volcanic body in the solar system. By definition, wouldn't that mean it has a volcanic sub-surface? Last time I checked, magma comes up from underground to the surface.

    • by blair1q (305137)

      Earth has a lot of lava flowing on it, but it mostly comes from plumes, and you don't get continuous magma until thousands of miles down through the mantle.

      Io could have had a lot of plumes.

      Instead, it's one big plume. Or rather, nothing to make plumes differentiated from the molten mantle.

  • From the summary:

    The global magma ocean about 30 to 50 kilometers (20 to 30 miles) beneath Io's surface explains the moon's activity.

    All these years, I thought it was physics that explained the moons activity.

    • by eriqk (1902450)
      I've been to some of Global Magma Ocean's lectures. They were fascinating. Great storyteller.
  • If a body is spouting Lava from its outer surface then that's more often than not a sign that its subsurface is also hot.
  • Where is the adamantine?
  • by mopomi (696055) on Friday May 13, 2011 @11:25AM (#36118400)

    A magma ocean is not a 100% liquid rock layer beneath the surface.

    The observations made by this team are consistent with a 50 km-thick layer about 50 km below the surface (that is, within the mantle) with >=20 volume% melt fraction. This work is based on how Io affects Jupiter's magnetic field.

    Other research teams have demonstrated, since the 1990s that Io should have a mantle with a >= 20 volume% melt fraction at some depth in the mantle--it was never clear where this magma ocean was located. This work is based on observations of the surface eruptions and models for how quickly silicate lavas cool.

    The fact that these agree is significant.

    A substantial portion of Io at 100 volume% melt would actually not work because pure liquid does not dissipate enough of the energy from the tidal forces to maintain 100 volume% melt. That is there's a feedback loop between Io's interior and the tidal flexing:

    * Too much liquid in the interior and the energy dissipation will decrease significantly, allowing the liquid to cool enough to solidify significantly.
    * Too little liquid and the interior would quickly dissipate enough tidal energy (in the form of friction) to significantly melt the interior.

    So, Io's orbital resonances keep a small part of its mantle molten at between 20 volume% and 50-70 volume.

    That there's now a depth associated with this magma ocean is actually quite significant. We can start better understanding the role volatiles play in Io's volcanism now that we know where the molten rock is coming from.

Fools ignore complexity. Pragmatists suffer it. Some can avoid it. Geniuses remove it. -- Perlis's Programming Proverb #58, SIGPLAN Notices, Sept. 1982

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