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Space

Venus May Have Active Volcanoes 45

An anonymous reader writes: The European Space Agency's Venus Express spacecraft has discovered hot lava flows on the surface of Venus, providing the best evidence yet that the planet may have active volcanoes. "[U]sing a near-infrared channel of the spacecraft's Venus Monitoring Camera (VMC) to map thermal emission from the surface through a transparent spectral window in the planet's atmosphere, an international team of planetary scientists has spotted localized changes in surface brightness between images taken only a few days apart (abstract)." Venus is fairly similar to Earth in size and composition, which suggests it has an internal heat source. One of the biggest mysteries about Venus is how that heat escapes, and volcanic activity could be the answer.
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Venus May Have Active Volcanoes

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  • It is generally believed that the earths magnetic field protects the atmosphere from being stripped away by the solar wind. Given that Venus has no (very small) magnetic field, this explains why the planet has such a dense atmosphere. Can anyone explain why a volcanicly active planet doesn't have a magnetic field? Isn't the liquid core what generates the field?
    • Can anyone explain why a volcanicly active planet doesn't have a magnetic field? Isn't the liquid core what generates the field?

      Probably because it has a very slow rotation.

      • +1. Venus rotates slower than i walk.
        • by linearZ ( 710002 )

          Venus is rotating in an oddball direction - against its orbit and accompanying tidal forces. The common explanation is that Venus got hit by something big enough to change its rotation, and may have even been what caused the atmosphere to be hosed.

          • Venus is the most important archetype in mythology. The stories tend to share a common theme of Venus going through a dramatic transition from an object of beauty to one of horror.

            What people have generally failed to realize is that Plato believed in a recent, human-historical event in the solar system, and he attributed all of the mythological archetypes to this single event.

            From Plato's Dialogues at https://books.google.com/books... [google.com]

            "Phaethon, the son of Helios, having yoked the steeds in his fa
            • Venus is the most important archetype in mythology. The stories tend to share a common theme of Venus going through a dramatic transition from an object of beauty to one of horror.

              Well, that is not a subjective statement at all.

          • by AK Marc ( 707885 )
            The oddball rotation is the same as everyone else, just so slow that when you account for it revolving around the sun, it's sunrise and sunset are the opposite of everyone else's.

            The lack of magnetic field is what makes the atmosphere dense. O2 is lighter than the other compounds in the atmosphere, so it floats to the top, where the solar wind strips the upper layers of the atmosphere. So if we were able to terraform the planet, changing the atmosphere to breathable, it wouldn't be a stable transformatio
      • It looks like Venus might have a frozen core as far as we know, at least from a few minutes of Googling and finding a couple hits mentioning that. -> http://cseligman.com/text/plan... [cseligman.com]

    • It is generally believed

      by whom? Citation needed.

      Can anyone explain

      Relative to the limits of your understanding, yes. Otherwise, I suppose you should ask the European Space Agency, because it would seem that they are, as of now, the experts in such questions.

    • Wait a minute. Mars' thin atmosphere is also explained by the small magnetic field. How could a magnetic field be held responsible for both?
      Especially, when you say the atmosphere would be stripped away by the solar wind. How dense it would be without being stripped away?

    • It is generally believed that the earths magnetic field protects the atmosphere from being stripped away by the solar wind. Given that Venus has no (very small) magnetic field, this explains why the planet has such a dense atmosphere.

      So, our magnetic field gives Earth a thick atmosphere, but Venus' lack of a magnetic field gives it an even thicker atmosphere?

      I'm missing something obviously....

  • Since there's no evidence of any plate tectonics whatsoever like Earth, that heat from tidal forces etc. that builds and dissipates any normal magnetic field...? I'm guessing here.

    • Since there's no evidence of any plate tectonics whatsoever like Earth,

      Venus doesn't seem to have the same tectonic style as Earth. At the moment. Beyond that ... I'm not going to speculate geologically. (Or even Veneraly. Or Venialy.) One thing that we don't know is how many different styles of planetary tectonics are possible (or if the number is significantly lower than the number of planets).

      that heat from tidal forces etc. that builds and dissipates any normal magnetic field...?

      Doesn't work : the mag

  • by Rei ( 128717 ) on Saturday June 20, 2015 @07:29PM (#49954109) Homepage

    They mentioned that the flow temperatures recorded in the hot pixels are colder than typical basaltic / rhyolitic flows and were speculating that they didn't catch freshly erupting material, but rather material that had a little time to cool. But I can't help but wonder.... does Venus have carbonatite [wikipedia.org] flows? They're colder, and if there's anything Venus isn't short on, it's carbonic compounds...

    (BTW, with those not familiar with carbonatite lava, its really weird stuff [google.com] - incredibly fast-flowing and smooth (often less viscous than water), erupts looking black or dark gray like oil, doesn't (visibly) glow during the day (just a fast moving black substance), at night it has a weird maroon glow, and it oxidizes to bright white as it ages)

    (Just one of many unusual types of volcano [google.com] :) )

  • and some asteroids are made if baking soda!

  • So Venus has hot flashes?
  • by bradley13 ( 1118935 ) on Sunday June 21, 2015 @03:38AM (#49955341) Homepage

    Maybe I'm out of date here, but I thought there was general agreement that moonless planets would just quietly cool from the outside in. No plate tectonics or vulcanism, because there are no tides to stir things up.

    Since TFA writes "These observations are close to the limits of the spacecraft’s capabilities and it was extremely difficult to make these detections", maybe this should be taken with a large grain of salt?

Every nonzero finite dimensional inner product space has an orthonormal basis. It makes sense, when you don't think about it.

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