Io’s atmosphere freezes and reinflates daily

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New data from the ground-based Gemini telescope suggests that Io’s sulfur dioxide atmosphere freezes and then reinflates each time the moon flies through Jupiter’s shadow.

A study led by SwRI’s Constantine Tsang concluded that Io’s thin atmosphere, which consists primarily of sulfur dioxide (SO2) gas emitted from volcanoes, collapses as the SO2 freezes onto the surface as ice when Io is shaded by Jupiter. When the moon moves out of eclipse and ice warms, the atmosphere reforms through sublimation, where ice converts directly to gas.

The data is somewhat uncertain, however, as it based on only two observations.



  • BSJ

    What the heck does ” based on only observations” mean!?

    Would you rather it had been based on computer simulations?

  • Whoops. I left out one word unintentionally. It now reads “based on only two observations”, which should explain my comment.

  • wodun

    That should pose some interesting challenges to any potential activities humans want to engage in on the surface?

  • Alex

    Wodun: There will be no future manned activities possible at Io’s surface, because Jupiter’s radiation is deadly there.

  • wodun

    Sure, but us sending robots is still a human endeavour. How corrosive is sulfur dioxide on Io?

  • Alex

    Wodun: “How corrosive is sulfur dioxide on Io?”. Good question, I guess that SO2 becomes corrosive at first place in combination with water in order to form H2SO3 or H2SO4. So, it depends from available water vapor, but I may wrong. Please remind, this is also a very, very thin SO2 atmosphere.

  • BSJ

    That makes more sense!

    For a second, I thought you were going all Al Gore on us. ;-)

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