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Huge Ocean Confirmed Underneath Solar System's Largest Moon

Posted by samzenpus on from the under-the-sea dept.

sciencehabit writes The solar system's largest moon, Ganymede, in orbit around Jupiter, harbors an underground ocean containing more water than all the oceans on Earth, according to new observations by the Hubble Space Telescope. Ganymede now joins Jupiter's Europa and two moons of Saturn, Titan and Enceladus, as moons with subsurface oceans—and good places to look for life. Ceres, the largest object in the asteroid belt, may also have a subsurface ocean. The Hubble study suggests that the ocean can be no deeper than 330 kilometers below the surface.

6 of 117 comments (clear)

  1. Life by hooiberg · · Score: 4, Insightful

    How did life start on earth? Water, with trace elements, under pressure, with a magnetic field to protect against the worst of the solar radiation.
    And what have we here? Water, with trace elements, under pressure, with a magnetic field to protect against the worst of the solar radiation.

    1. Re:Life by abies · · Score: 5, Insightful

      Except it is not a solar radiation you need protecting against (Sun is very far), but Jupiter radiation. Unfortunately despite magnetosphere, Ganymede gets around 8 rem of radiation per day (http://en.wikipedia.org/wiki/Colonization_of_the_outer_Solar_System#Ganymede), which is bit too much for life as we know it. Fortunately, it is not going to be an issue 300km below the surface - but at that depth, you don't need magnetosphere anyway.

      I think that biggest problem for life there would be availability of energy. 300km of crust is probably shielding external energy too well, so internal heat would be probably only viable source of that. Might be not enough to sustain life (or even more, to produce it randomly)

    2. Re:Life by hooiberg · · Score: 5, Insightful

      On the other hand, heat built up by tidal forcing of Jupiter will also not be able to escape easily, through such a thick crust. Remember that we have many deep-ocean creatures on earth, where there is no light, and the water is so cold that it is barely liquid. (zero to three degrees Celsius).

      Actually, it has been estimated there are so many deep-ocean species, that bioluminescence might be the most common method of communication on earth.

    3. Re:Life by Rei · · Score: 3, Insightful

      And you know that those are the requirements for LAWKI how? Ignoring the fact that there could be entirely different requirements for other entirely types of life elsewhere, you have no clue how the earliest forms of life on Earth began.

      If Titan's natural abiotic organic chemistry laboratory offers any clues, for example, the start of life could have come because of ionizing solar radiation, and in the absence of water, and only later developed into our present form. On Titan solar ionizing radiation builds complex organic compounds, some having been measured at over 10000 daltons, of carbon, hydrogen, and nitrogen, which raises the potential of catalytic cycles.

      There have been countless proposed mechanisms for the earliest forms of autocatalysis that could have led up to the theoretical RNA world that could have led to our present world. And orders of magnitude more not yet conceived that could potentially have done it. It's silly to pretend that we have any clue exactly what the requirements are for the earliest "ancestor" to life on Earth. We don't know whether it developed in an ocean, on land, in a lake, in the soil, in rocks deep underground, in the troposphere, in the exosphere, in space... we really don't know. We don't know where it developed and we don't know what it was, and we don't know if it was the only way life could form (but I'd wager "no").

      --
      "Are you hungry? I haven't eaten since later this afternoon." -- Primer
    4. Re:Life by Anonymous Coward · · Score: 4, Insightful

      On the other hand, heat built up by tidal forcing of Jupiter will also not be able to escape easily, through such a thick crust.

      Heat "build-up" is not enough, you need a heat gradient with some sort of heat flow. Life and chemistry doesn't bypass thermodynamics. If the water and ground below it is very even, with the gradient in solid material above, there might not be enough of an energy source to allow life to form.

  2. Re:That can't be right... by Anonymous Coward · · Score: 2, Insightful

    because the Greens tell us that we'll soon have used up all the water on the Earth,

    When you slap labels on your "enemies" and then ascribe to them absurd positions you're doing yourself a disservice. You stop thinking rationally and dismiss any notion that doesn't already fit with your ideas.