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Space Science

New Find Boosts Prospects For Life On Distant Moons 98

Posted by samzenpus
from the I-wonder-who-owns-that-moon dept.
sciencehabit writes "Imagine life on an Earth-like moon, one so close to its gas giant host that its landscape is bathed in a dusklike planetary glow. Such places are not only possible but also probable, according to a new study, which finds that as many as 5% of gas giant planets orbiting their stars at Earth-like distances may harbor habitable 'exomoons.' According to simulations, alien gas giants (like our Jupiter and Saturn) could pull in earth-like planets from the interior of their young solar systems. Though many of these planets would crash into the gas giants or later be flung into space, some would evolve stable orbits and stable climates, eventually setting the stage for life."
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New Find Boosts Prospects For Life On Distant Moons

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  • Err, waitaminute. (Score:2, Interesting)

    by Penguinisto (415985)

    ...one would think that the radiation would pretty much sterilize any object that damned close, no?

    Sure, there are bacteria that thrive in radioactive environments, but there's a diff between fissile waste and a massive gas giant's output...

    • What sort of radiation?
      • by Anonymous Coward

        I think he means the radiation from the parent star, because most of the gas giants they have found so far are close to their parent star (makes it easier for us to find them).

        If the gas giants have a magnetic field as strong as Jupiter's, a closely orbiting moon might well be shielded by it from a lot of the charge particles from the sun, much as our Van Allen belts do.

        The UV, etc, is still going to be nasty unless the planet has an atmosphere that blocks a lot of that.

        • So, there's an Earth-like body, which I took to mean atmosphere, composition and climate, going round a star at an Earth-like distance. Is there any problem with radiation coming from gas giant nearby?
        • Re:Err, waitaminute. (Score:4, Informative)

          by Anonymous Coward on Wednesday June 22, 2011 @08:20PM (#36536846)

          Jupiter's magnetosphere produces intense radiations belts around the planet. All of Jupiter's moons are constantly bathed in enormous amounts of radiation.

          • by Anonymous Coward

            All of Jupiter's moons are constantly bathed in enormous amounts of radiation.

            What's your point?

            New bacteria found fueled by radiation [washingtonpost.com]

          • I've always wondered if a moon had a magnetic field like the earth's. If that would be enough to shield it.

          • by dpilot (134227)

            I remember hearing this, realizing that "Farmer in the Sky" wasn't even physically possible, not just politically, economically, socially, and technologically, and being disappointed.

      • by Anonymous Coward

        I'm guessing he means radiation from the gas giant itself. The radiation near Jupiter is enough wreak havoc with or fry space probes. I'd imagine that wouldn't bode well for anything living.

      • "In truly great magnetic fields like those of Jupiter, atomic particles may be heated to millions of degrees, and a great electric arc flows between the planet and its moon lo." - NASA [nasa.gov]
    • by Lokitoth (1069508)
      Personally, I would be much more worried about tidal forces. Though if it is far enough away from the gas giant...
      • Personally, I would be much more worried about tidal forces. Though if it is far enough away from the gas giant...

        I'd be more worried about Death Stars showing up and ruining my plans for rebellion. Hopefully they exit hyperspace on the far side of the gas giant giving me enough time to launch a counter assault......

    • by moderatorrater (1095745) on Wednesday June 22, 2011 @08:15PM (#36536794)
      Just like the intense heat of the yellowstone mudpots or the ocean volcanic vents would prevent life from being there? Or the extreme cold of the arctic? Or any of the other places that we thought life couldn't exist until we found it there?
      • Re: (Score:3, Interesting)

        by todrules (882424)
        Or the fungus in Chernobyl that feeds on radiation.
      • Or any of the other places that we thought life couldn't exist until we found it there?

        Not quite. We're talking about life starting in an environment like that, not life evolving into that environment from a more comfortable one.

        • by Anonymous Coward

          Or any of the other places that we thought life couldn't exist until we found it there?

          Not quite. We're talking about life starting in an environment like that, not life evolving into that environment from a more comfortable one.

          Live didn't start in a comfortable environment on Earth, at least not how you define it. In fact, life *created* your comfortable environment. All the oxygen in the atmosphere was put there by organisms that had oxygen as a byproduct of their metabolism. Aerobic organisms came later, once the atmosphere was rich with the gas.

          • So the surface of Earth was below freezing or several hundred degrees until life took over?

            • Single celled life appeared at the same time the Earth cooled enough to have a liquid ocean, multi-cellular life appeared several billion years later at the end of the last "snowball Earth" event.
        • Not quite. We're talking about life starting in an environment like that, not life evolving into that environment from a more comfortable one.

          We have exactly one planet with one example of life starting. We have no idea what circumstances can lead to life starting. We do know, however, that life will fill pretty much any niche there is. With the lack of knowledge we have, it would be foolish to believe that we can rule out any environment as a possibility for life.

    • Re: (Score:1, Redundant)

      Why do ET life research imply that whatever we should find must have the same weakness and conditions as found on the earth? The only thing in common should be evolution and if you start from some extreme conditions (extreme from our point of view) then you evolve your way around to them. Life that evolves from planet with strong gravity would be massive and strong, Life evolving in methane atmosphere would have bio-combustion chambers instead of lungs. etc.

      It's like making first contact and waiting for the

      • Life that evolves from planet with strong gravity would be massive and strong

        More likely light weight and strong but I can see from the rest of your post you're not interested in heuristics based on what is more likely, it seems you would rather do a brute force search of the universe.

        • by Nox3173 (1495587)
          Um, wouldn't you actually increase bone mass and density in a developing organism in a high gravity environment, an effect similar to the opposite effect of the bone mass and density loss experienced by low gravity space flights?
          • Things with exoskeletons (the majority of critters) would be smaller, gravity is known to dictate their maximum size here on Earth. Things with internal skeletons might go the other way but are also ultimately limited by gravity. They may develop bird like bones to increase size while retaining strength and reducing mass or they may even develop bones that are made of something stronger and lighter than limestone.
        • Well obviously you have to apply some filter when you're looking for life in something as big and massive as the universe I get that. I wouldn't start the search from a brute force approach, but I'll try to keep the window as open as possible and not just discard exoplanets because they don't share $property that earth exhibits.

          Anyway, ET life is cool and all, what happens if we confirm that 500 light years from earth theres life? (besides media, experts and marketing rage) seems like everybody actually bel

    • by Anonymous Coward

      Actually, the radiation would likely aid evolution greatly.
      It will create wild environments, things constantly mutating.
      And, possibly, eventually create lifeforms that are heavily immune to the effects of radiation, probably even using and depending on it for energy.
      Given time after this, it could lead to more complex life, possibly life that has smaller cells but larger numbers of them since larger structures are more likely to fail due to hue mutagenic damage.

      It might not happen on the same time-scales of

      • by arth1 (260657)

        I think we can all agree that Mars was probably alive at one point in the past.

        Um, no. That's wishful thinking.

        Of course, Mars has been rusted away to a big red ball, which all missions so far have apparently ignored.

        Tiny red ball, you mean. At a mass of around 10% of Earth, Mars is closer to Mercury and the larger moons than it is to Earth and Venus. It's also half again as far from the sun as Earth is, and with its radius being half of that of Earth, it gets hit by only a small amount of sunlight energy compared to Earth.

        In short, Mars is a pretty inhospitable little ball, but it's a stepping stone on the way towards the real prizes, the gas giants.
        From a DNA-based life point of view

      • by 1u3hr (530656)

        Actually, the radiation would likely aid evolution greatly. It will create wild environments, things constantly mutating.

        No, that's comic book "science". Radiation isn't necessary to speed up evolution. There is plenty of variation already. Massive random mutations are usually simply lethal. Evolution proceeds via incremental changes. What speeds up evolution is an environment with unfilled niches -- see e.g. the Galapagos, where the relatively small number of animals (e.g. turtles) and birds (e.g.finches) that colonised it quickly evolved into numerous species to exploit different food sources, etc. Or how we mammals got our

    • by sunspot42 (455706)

      A large moon (Mars sized or larger) would almost certainly be geologically active if it orbited a large gas giant. Indeed, even smaller worlds without a lot of internal decay heat of their own would retain a molten interior far longer than a lone planet the same size would, because of the tidal forces exerted by the large parent planet (and any additional satellites it might have). These geologically active large moons are likely to have their own magnetic fields, the same way earth does, and those would

      • by jc42 (318812)

        A really big gas giant (say, 5-10 times the mass of Jupiter) has an enormous gravity well, but we don't know if its magnetic field and radiation belts scale in the same proportion.

        And the gas giants we have available would suggest that we not make guesses about magnetic-field strengths of gas giants until we have a lot more direct data. Jupiter's magnetic field is much stronger than Earth's; Saturn's is somewhat weaker. The mechanisms that produce these fields aren't understood very well. This gives a lot of latitude to science-fiction authors, but not much actual information about what might be out there in our real universe.

        One thing we can probably safely predict is that any

        • by sunspot42 (455706)

          Callisto has less tidal heating because it's much further out - about 2 million km if memory serves. I think Io is closer to 400,000km from Jupiter. Europa orbits not too much further out, at under 700,000km, then Ganymede at 1 million km. So Io is getting pushed and pulled on by tugs from Europa and Ganymede, not to mention Jupiter itself. Callisto in comparison experiences very weak tugs from Ganymede, and not much at all from Europa or Io. And Callisto experiences those tugs less often, since its o

    • by IrquiM (471313)
      Erh... Water? It provides radiation shielding.
    • by kalirion (728907)

      Life will find a way.

  • This is good because (Score:4, Interesting)

    by florescent_beige (608235) on Wednesday June 22, 2011 @07:58PM (#36536646) Journal

    Now we know the probability of life developing on a distant moon has gone up from .2a to .25a where a is an unknown value between 0 and 4

    That's an exobiology arithmetic joke you cretins.

  • And then there is the (small) logistic problem of building a spaceship that could get there. As in, infinite fuel and traveling without a reasonable timeframe for a human being.

    • by dudpixel (1429789)

      And then there is the (small) logistic problem of building a spaceship that could get there. As in, infinite fuel and traveling without a reasonable timeframe for a human being.

      This is not entirely correct.

      Yes we (apparently) lack a way of getting there, or anywhere close for that matter.

      The problem is that you suggested we need some sort of fuel (inferring a solid/liquid fuel like we use in spacecraft currently). The other problem is that of time.

      If you solve the first problem, the second should become trivial. The "fuel" needs to be something that exists not just on earth. It must involve nullifying the effects of gravity.

      I'm not sure if physics has reached a point where we c

      • by dudpixel (1429789)

        Let me also add that without any known way of getting there (and no solution in sight), I dont see the point of these studies.

        • Maybe we'll find something so interesting, it will inspire us to go out and invent a way to get to it?
          • by dudpixel (1429789)

            but surely we already have enough motivation....although on second thoughts, you are probably correct in that it is the governments and the general populous that need to be convinced, rather than scientists and engineers. The governments (and by extension, the people) need to allocate funds and resources for such things to happen...fair enough.

  • by blair1q (305137) on Wednesday June 22, 2011 @08:15PM (#36536790) Journal

    1. Insane tidal forces. The whole atmosphere getting thicker and thinner throughout each day. Oceans sloshing up and down by hundreds of meters in depth - not length, depth - twice a day along coastlines.

    2. Insane temperature variances as the "moon" is eclipsed by the planet for a good portion of every "month". Whole oceans freezing over and thawing out every few thousand hours.

    So, really, being at an earth-like distance from a sol-like star is bollocks for deciding whether there's life on such a rock.

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Wouldn't this result in tidal locking and thus synchronous rotation, making everything stable once it's in effect?

    • Re:Caveats: (Score:4, Informative)

      by SixAndFiftyThree (1020048) on Wednesday June 22, 2011 @08:32PM (#36536934)

      1. The moon would be tidelocked, if it were close enough to have such huge tides, no question.

      2. Depends on the orbital period; three of Jupiter's Galilean satellites have periods of a week or less, and a quick calculation based on the diameter of Jupiter versus the diameters of their orbits suggests that none of them is in total eclipse for more than a few hours ... better numbers here [alpo-astronomy.org]. Since I routinely survive a twelve-hour night with no ill effects, the eclipse seems to be a minor problem. A tidelocked planet would have a day equal to its month, though, which might be a problem if the month were more than two or three days, but a lot would depend on the presence of oceans, which are huge reservoirs of heat, and on wind patterns.

      "Those who refuse to do arithmetic are doomed to talk bollocks."

      • by dryeo (100693)

        Tides would depend on whether there were other Satellites of significant size in a close orbit. Most of the major Satellites of Jupiter are heated by tidal effects even though tidally locked.

        • Good point indeed. Bear in mind that satellites in orbits very close to each other would be unstable: the orbits would change in a time much shorter than it would take life to evolve. IIRC the closest pair of Galilean satellites are in a 3:2 resonance ... lemme see ... actually 2:1 by http://en.wikipedia.org/wiki/Galilean_moons [wikipedia.org] and their closest approach is 250,000 km, which makes for tides about four times as strong as on Earth (tidal force is inversely proportional to the cube of distance). With bigger

          • by dryeo (100693)

            I'd think that any system with 2 Earth-sized satellites would have them spaced further apart or only one Earth-sized and the rest closer to moon-sized. Either way resulting in tides closer to what we experience.
            Hopefully one day we'll have real examples.

      • by blair1q (305137)

        Okay. Tide locking. Now "night" is weeks long, and so is "day". No chance of forming a persistently temperate zone. The proper conditions for biochemistry would exist for a couple of hours every few weeks.

        The bollocks are in your court.

    • by Anonymous Coward

      Those are possible, but moons are also usually tidally locked, meaning no severe stresses. Jupiter's biggest moons have orbital periods on the order of a few days, so even with one side always facing the host planet, you could get an earth-like cycle. And half the moon wouldn't even see the daily eclipse, because it'd be night there anyway. With a thick enough atmosphere (which, if it's habitable in the first place, it'll have), the eclipse wouldn't freeze the oceans. There are plenty of ways to make a worl

    • Re: (Score:2, Funny)

      by Anonymous Coward

      I saw a documentary once where a number of furry natives had helped armed rebels overthrow an evil empire, and they lived in a scenario just like this one!

      • by blair1q (305137)

        But they had help. And the empire, while evil, was also stupid. Who brings two-footed walkers into a forest without they're the ones that can walk on logs?

    • Re:Caveats: (Score:4, Informative)

      by canajin56 (660655) on Wednesday June 22, 2011 @09:21PM (#36537242)
      No to number 2. Yes to number 1, but it's not that bad. If you're as close as the "artist's rendition" drawings in the picture, where the gas giant is taking up half of the sky, then yeah, the tidal forces would be millions of times greater than the moons. But that's so absurdly close it doesn't bear thinking. If you take Saturn as a "typical" gas giant, and put a moon 400,000 KM away, then although the tidal forces would still be 10,000 times as great, the size in the sky of Saturn would only be 16 times as great as the Moon. That might cause more frequent eclipses, but they're not going to last much longer. Because at that distance the orbital period of our moon will be 24 hours. A worst-case eclipse would last for 30 minutes, and occur once per day. Depending on the specifics of the orbit, they might occur a whole lot less than that. (We don't get an eclipse every single month). But those tidal forces are still pretty awful. Except that at those forces, the moon would certainly be tidally locked. So although there would be severe stretching because of these forces, the pull would always be in the same direction due to the tidal locking. So there would actually be less severe tides than Earth has.
    • Oceans sloshing up and down by hundreds of meters in depth - not length, depth - twice a day along coastlines.

      That would make for some awesome extreme surfing.

    • Insane tides only while the moon tidally locks to the primary.

      Also depends on the distance to the primary. While gravity goes down with the square, tidal forces go down with the cube of distance.

  • by Anonymous Coward

    ...developed on a moon. Would the fact they they revolve around a planet that revolves around a sun change the way their society develops? Would they have "planet gods" as well as "sun gods"?

    Yeah, sure, there's a lot of interesting science about the development of the creatures in the first place, but I'm more interested in what their society and culture might be like.

  • TFT

    New Find Boosts Prospects For Life On Distant Moons

    Thanks God!!! From now on (and because of that), those moons do have some chances to develop life...

    • Thanks God!!! From now on (and because of that), those moons do have some chances to develop life...

      Only if the scientist who wrote that entered the sphere.

      • by eyenot (102141)

        Thanks God!!! From now on (and because of that), those moons do have some chances to develop life...

        Only if the scientist who wrote that entered the sphere.

        Or if the formation of life is somehow dependent on observation (via Heisenberg "uncertainty"). In which case moons of this type in our observable universe would indeed have increased in their chance of producing life.

        • by jc42 (318812)

          Thanks God!!! From now on (and because of that), those moons do have some chances to develop life...

          Only if the scientist who wrote that entered the sphere.

          Or if the formation of life is somehow dependent on observation (via Heisenberg "uncertainty"). In which case moons of this type in our observable universe would indeed have increased in their chance of producing life.

          Actually, you don't need Heisenberg's Uncertainty Principle; you just need some basic statistical knowledge.

          A similar example from a few years back: There was a widely-echoed calculation by biologists that there was about a 50% probabability that there was a large mammal (for some definition of "large") that was still "unknown to science", i.e., not described in The Literature. Then in 1999 there was a printed report of new species of deer [wikipedia.org] in Southeast Asia. When jounalists asked scientists if this me

  • Forest moon of Endor, watch out for any strange "unfinished" artifacts...

  • Moons orbiting a gas giant planet would also solve the tidal locking problem for red dwarf stars.

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