Icy Moons Are Ocean Worlds

(mceglowski.substack.com)

105 points | by worldvoyageur a day ago ago

10 comments

  • merek 20 hours ago

    Set your calendars:

    Europa Clipper, launched 2024, starts Europa flybys on March 2031

    Dragonfly, hopefully launching July 2028, arriving on Titan 2034

    https://en.wikipedia.org/wiki/Europa_Clipper

    https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe)

  • yellowapple 17 hours ago

    > This remarkable transformation in our understanding is the result of just three missions: Voyager, Galileo, and Cassini—along with some computer modeling and hard staring by the Hubble and Webb space telescopes.

    Seems odd to neglect to mention New Horizons immediately after mentioning the probable existence of liquid oceans under Pluto's surface, a finding made possible thanks primarily to New Horizons.

  • exhilaration a day ago

    Great read, other than Europa I wasn't aware of these other candidate ocean moons.

  • miohtama a day ago

    TIL

    > The radiation environment around Europa is punishing; an astronaut standing on the surface would get a fatal dose in about a day

    • kaseijin a day ago

      True for all the Galilean Moons more or less. Their orbits all lie within the Jovian equivalent of the Van Allen belts. And Jupiter's magnetic field is much stronger than earth's.

      • sennalen 21 hours ago

        Not Callisto. Being within Jupiter's magnetosphere but out of reach of Io's shenanigans makes it one of the mildest radiation environments in the solar system.

      • idlewords 21 hours ago

        Not true at all, the daily dose on Ganymede (which has a magnetic field of its own) is ~70 mSv/day, and Callisto is 0.1 mSv/day.

        Io, meanwhile, is 35 Sv/day. Location really matters among the four Galilean moons.

  • pvaldes a day ago

    Beautifully designed article. Very cool images and diagrams.

    > We want rocks in contact with water,

    But there is ice compressed between the water column and the xenoceanic bottom, ok. I see the problem.

    What about rocks in the surface of the water?. Some volcanic rocks can float.

    • andrewflnr 2 hours ago

      > What about rocks in the surface of the water?. Some volcanic rocks can float.

      This is... not something you lay plans on. Even on Earth, these rocks are formed at surface pressure, just barely float, and don't float for long (I've tried). If they form in the deep ocean, I'm guessing the pressure isn't going to let the bubbles be big enough to create bouyancy at all. Either way they would be super rare.

    • Gravityloss 3 hours ago

      I guess I'm now officially old and cranky, as planetoids receiving glow-ups was just a bit much as a term.