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Space Science

Is Jupiter Dissolving Its Rocky Core? 181

Posted by Soulskill
from the told-you-not-to-drink-all-that-soda-pop dept.
sciencehabit writes "Jupiter is the victim of its own success. Sophisticated new calculations indicate that our solar system's largest planet, which weighs more than twice as much as all of the others put together, has destroyed part of its central core. The culprit is the very hydrogen and helium that made Jupiter a gas giant, when the core's gravity attracted these elements as the planet formed. The finding suggests that the most massive extrasolar planets have no cores at all."
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Is Jupiter Dissolving Its Rocky Core?

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  • Hey, it has to have a core. Diamonds are forever.
  • by youn (1516637) on Monday December 19, 2011 @03:13PM (#38425602) Homepage

    get at least a quad core... time for an upgrade haha :)

  • Monoliths (Score:5, Funny)

    by OakDragon (885217) on Monday December 19, 2011 @03:13PM (#38425612) Journal
    Just need to toss in several hundred thousand black monoliths, and we'll have a new star in the firmament.
    • by mrmeval (662166)

      I believe there is a paper that describes how to trigger a self sustaining fusion reaction in Jupiter's atmosphere. I believe the paper was triggered by 2001 when it came out. I am an ineptly erased slate for anything I experienced prior to 2000 so ...

  • Weight? (Score:2, Insightful)

    by wisnoskij (1206448)

    "which weighs more than twice as much as all of the others put together"
    I wonder if this guess is still correct. I would assume this weight was appropriated by assuming the planet had a solid core?

    • Re:Weight? (Score:5, Insightful)

      by pixelpusher220 (529617) on Monday December 19, 2011 @03:20PM (#38425678)
      Dissolving a solid into a liquid doesn't change it's mass.
      • by Baloroth (2370816)

        Yeah, but it does wonders for it's weight.

        Also, you can't really use the term "weight" for a planetary core. Since the core is at the center of gravity, it has no weight whatsoever. Well, except for towards the Sun, I suppose. Not sure if TFS would be correct or not about the weight in that respect.

      • by LWATCDR (28044)

        That and under that tempiture and pressure we are talking about a liquide very unlike any liquide we normally deal with.

    • You do realize that liquid rock has the exact same mass as solid, right? They aren't saying that this bodies never had cores but rather that the solid core was eroded.
      • Re:Weight? (Score:5, Funny)

        by dougisfunny (1200171) on Monday December 19, 2011 @03:29PM (#38425788)

        Next thing you'll tell me is that a pound of feathers weighs as much of a pound of bricks!

      • Re:Weight? (Score:5, Interesting)

        by Anonymous Coward on Monday December 19, 2011 @03:59PM (#38426120)

        You do realize that liquid rock has the exact same mass as solid, right?

        That's mostly correct, but as heat is a form of energy and E=mc^2, a rock changed into liquid state would mean that it weighs oh-so-slightly more. For some napkin calculations: the specific heat of iron (at 273 K) is 0.45 J/(K g) meaning that if we had a thousand tons of iron (1E9 g) and increased the temperature 1000 K then the increase of mass would be: 0.45*1E9*1000/(3E8)^2 = 5E-3 g. All that mass and energy for a full 5 milligrams, which is why it's mostly negligible

        Disclaimer: I know that the specific heat changes (quite a bit) with temperature but I wanted to keep the example simple.

      • Did not read the original article, but I would assume that it likely changed it density as well.
        Meaning that lots of liquid core could have been pushed to the surface making the planet appear bigger and more massive from the outside.

        • by HiThere (15173)

          Probably not. The density of the core decreases, but the density remains pretty high. (The pressure is high enough to liquify hydrogen at a reasonable temperature.) And while the core has now disappeared, there is a larger volume of denser liquid.

          Besides, what you see when you look at a gas giant is the atmosphere. That's not going to change measurably.

      • You do realize that liquid rock has the exact same mass as solid, right?

        To be perfectly technical, no it does not. Molecular bonds and heat have mass too...

    • Re:Weight? (Score:5, Informative)

      by camperdave (969942) on Monday December 19, 2011 @03:26PM (#38425754) Journal
      No. It is estimated by the orbits of it's satellites, using Kepler's laws. If you know the period, eccentricity, and size of a satellite's orbit, you can work out the mass of the object that the satellite is orbitting. It has nothing to do with how much of that object is solid.
    • by nedlohs (1335013)

      Nope.

      We "weigh" planets by observing the gravitational force acting on a space craft (whose mass we know) we send close to them. Or by measuring the mass of something else (say by observing a space craft near it) and then observing how it interacts gravitationaly with the planet in question.

      You can also do some math with pulsar timings to see periodic errors due to the barycenter of the solar system not being exactly where you thought - which will also give you the planetary masses (well the planet plus th

    • by v1 (525388)

      weight is really easy to figure out, or what I'm assuming you're talking about, mass, since it produces the easily observable effect of gravity

      Remember that "weight" is the effect of gravitational attraction between separate bodies that possess mass. You can't talk about "weight" unless you're referring to at least two objects. (usually with great differences in mass, such as a planet and an object on said planet)

  • by Trepidity (597) <delirium-slashdo ... org minus author> on Monday December 19, 2011 @03:19PM (#38425674)

    As far as I know, that question was still open to at least some debate. It's hypothesized that there should be a solid core based on the mineral composition and some simulations, but I don't believe there's any direct evidence of it, at least until the mission (mentioned in the article) to measure its gravitational field with an orbiting probe reaches it.

    • As far as I know, that question was still open to at least some debate. It's hypothesized that there should be a solid core based on the mineral composition and some simulations, but I don't believe there's any direct evidence of it, at least until the mission (mentioned in the article) to measure its gravitational field with an orbiting probe reaches it.

      Wouldn't that apply to Earth's core as well? I mean, as far as I'm aware no one has ever drilled all the way to the center of the planet, so what evidence (beyond hypothesis) is there that Earth's core is what we think it is?

      • by Trepidity (597) <delirium-slashdo ... org minus author> on Monday December 19, 2011 @03:33PM (#38425820)

        There's some evidence beyond only mineral composition for the earth's core, mostly from seismic data; the discontinuities observed in seismic wave travel put constraints on what has to be the case at different layers. At least, it's more data than we have about the interior of Jupiter, which afaik is entirely based on mineral composition and modeling.

        • by vlm (69642)

          There's some evidence beyond only mineral composition for the earth's core, mostly from seismic data; the discontinuities observed in seismic wave travel put constraints on what has to be the case at different layers. At least, it's more data than we have about the interior of Jupiter, which afaik is entirely based on mineral composition and modeling.

          Some data comes from detailed magnetic field monitoring, makes sense since it seems to be the cause of the earths magnetic field.

          http://en.wikipedia.org/wiki/Inner_core#Dynamics [wikipedia.org]

      • They have "drilled down" to the Earth's core with sound waves. They use seismic charges to bounce sound waves off the core.
    • Isn't it theorized by some that the pressure is high enough in Jupiter that the hydrogen is metallic? Does anyone really understand the metallurgy of metallic hydrogen?

  • ...central core made of iron, rock, and ice. .... The temperature there is approximately 16,000 kelvin—hotter than the surface of our sun....

    Okay, maybe ice means something else on Jupiter. Can someone explain how Jupiter's core can have ice that doesn't melt?

    • Re:core is icey hot? (Score:4, Informative)

      by ZombieBraintrust (1685608) on Monday December 19, 2011 @03:38PM (#38425896)
      Ice doesn't mean cold water. Ice is solid water. Water is liquid, solid, or gass depending on temperature and pressure. There is alot of pressure at the core of Jupiter.
      • Re: (Score:2, Funny)

        by Obfuscant (592200)

        There is alot of pressure at the core of Jupiter.

        That's nothing compared to being the core of Saturn. You scrub and scrub and scrub and nothing gets rid of those rings, and then Neptune comes home and wants his dinner and doesn't understand that you've been working hard all day. 'Get me a beer!' he hollers as he plops his ass down into the big comfy chair and starts watching Wheel of Fortune.

        I tell 'ya, being the core of a planet ain't all wine and roses, I tell 'ya.

    • Re:core is icey hot? (Score:4, Interesting)

      by polymeris (902231) on Monday December 19, 2011 @03:48PM (#38425994)

      High pressure from all that mass, possibly? [wikimedia.org] Just speculating here.

    • by Baloroth (2370816)

      ...central core made of iron, rock, and ice. .... The temperature there is approximately 16,000 kelvin—hotter than the surface of our sun....

      Okay, maybe ice means something else on Jupiter. Can someone explain how Jupiter's core can have ice that doesn't melt?

      Pressure.

  • by miserere nobis (1332335) on Monday December 19, 2011 @03:45PM (#38425962)
    Oh no! We better drill a hole to the center of Jupiter and explode a nuclear bomb to fix it, because that makes sense!
  • âZ"We're pretty sure it has nothing to do with our decision to smash a huge plutonium powered space probe into it or with the resulting huge purple 'second spot' caused by the resulting plume, which was so large it was visible to backyard telescopes and in general was a sort of shocking embarrassment to NASA when it occured."

    "No, this disintegration now suddenly occuring just a few years after that incident has nothing to do with us. Jupiter was in the middle of killing itself, anyways. It was only a m

  • What happens to the silica? From my skimming of TFA, it appears that the experiment only involves the dissolution of the MgO component. There should still be gobs of MgSiO3 (or at the very least SiO2, if the MgSiO3 breaks down into its constituent oxides at the high pressures) hanging around down there.

    • by Xerxes314 (585536)

      According to TFA, the MgSiO3 dissociates into SiO2 and MgO under Jovian core conditions. They don't calculate what happens to the SiO2, but assume that its solubility is similar to the MgO component. So that would mean that the SiO2 also goes into solution in the Jovian core.

      Also of interest (at least to me) but not addressed in this paper is what happens to the nickel-iron component of the core. Perhaps they figure Jovians don't have enough to worry about, since they form so far from the center of the prot

      • by Convector (897502)

        That's a good point about the iron. There should be some, but at a far lower abundance than the silicates. Still, we're probably talking a few Earth masses of metal (real, actual metal, not what astrophysicists call metal).

        I did notice that they speculated that the SiO2 should also dissolve, but I don't really know how valid that assumption is.

  • by ravenscar (1662985) on Monday December 19, 2011 @04:59PM (#38426818)

    Jupiter is no longer hard core.

  • My guess is that in the lengthy process that a solar system and/or planet evolves, in which we know nothing about, but can only theorize (as no one has ever lived long enough to see a planet go from a to z), is it possible that there was a core, but the core now has disappeared(on purpose) and that this will create a small vacuum where by the gasses will draw inwards and create a molten core, which in turn will start forming an earth like planet at a much smaller scale, so the large becomes small, and habit

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