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Space Science

Planet Discovered with a Massive Core 265

Posted by Zonk from the who-doesn't-love-a-good-massive-core? dept.
helioquake writes "A collaboration of astronomers discovers possible a 'Rossetta Stone' of planetary formation study, reported by San Francisco State Univerity and Subaru Observatory. This new planet, orbiting around G-star like our Sun (HD 149026), weighs roughly equal to that of Saturn, while its size is significantly smaller in diameter. Planetary modeling suggests that the core of the planet alone must have 70 times more mass than Earth, indicating the possible existence of a metallic solid core inside the planet. Just like the rocky planet discovered earlier, the finding of this dense-core planet may lead to better understading of the formation of rockey planets in the Universe."
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Planet Discovered with a Massive Core More

Planet Discovered with a Massive Core

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  • Time for IPX (Score:4, Funny)

    by vandon ( 233276 ) on Friday July 01, 2005 @10:31AM (#12961097) Homepage
    I'd say it's time for IPX to head out and start mining that core. There's probably quite a bit of rare minerals in it.

    • I'd say it's time for IPX to head out and start mining that core.

      An offtopic mod, and a comment about planetary rape - I guess you fell for the common mistake of assuming geeks are familiar with SciFi ;-) "What is this Babylon 5 of which you speak?"

      Back on-topic, what is the deal with extra-planetary mining? Legally? Is it just a matter of time, or are other planets protected like Antartica, say?

      • Drill's too short.

      • Re:Time for IPX (Score:3, Insightful)

        by Surt ( 22457 )
        There are legal restrictions based on the space treaty:
        http://www.oosa.unvienna.org/SpaceLaw/outersptxt. h tm [unvienna.org]

        But realistically, the only reason we don't exploit other planets or antarctica is that its too difficult compared to expoiting something on our own territory. Believe me, if they discover massive amounts of oil in antarctica, and an easy way to extract and ship it, we'll be doing it as fast as possible.

        • Dammit, sir, you provided an informative and hopeful answer, and then had to go and ruin it by reminding me of humanity's greed. Thank you very much.

          ;-)

          Seriously, the "Treaty on Principles Governing..." was exactly what I was looking for.

          • Greed is like any other form of 'Self Satisfaction'.

            It's nothing to be ashamed of. It's nothing to be proud of either.

    • "The time of IPX is over," said Eric Schmidt, "the future is pure IP." Within weeks, he had run Sniffers in every wiring closet to ensure no further SAPs or RIPs were present and announced a release date for Novell NetWare 5.0.

      Eric Schmidt is now a billionnaire and much, much cooler than he used to be.

      The two above mentioned items are not related.

  • how do they determine the weight/mass of a planet that's that far away? Or is it more of just a guess based on what light it refracts/emits/absorbs?

    • Re:weight (Score:4, Informative)

      by rsynnott ( 886713 ) <synnottr@tcd.ie> on Friday July 01, 2005 @10:35AM (#12961137) Homepage
      Its influence on the star's wobble, AFAIR.

    • Re:weight (Score:3, Informative)

      by Foolomon ( 855512 )
      Undoubtedly they measure it by the effect it has on its surroundings. Mass equates to gravitational pull, which can manifest itself in the curvature of light as it passes by it.

    • Re:weight (Score:5, Informative)

      by InternationalCow ( 681980 ) <mauricevansteensel.mac@com> on Friday July 01, 2005 @10:39AM (#12961192) Journal
      It's not too difficult, conceptually. The star's mass is a function of its brightness. So, you already know the mass of the star. The orbiting planet causes the star to wobble a bit. The more massive the planet, the more the star wobbles. Weight is not the same as mass, by the way. Weight is what you get when you place a mass in a gravitational field. More info on this: http://ethel.as.arizona.edu/~collins/astro/subject s/srchplanet5.html [arizona.edu]

      • Re:weight (Score:4, Informative)

        by helioquake ( 841463 ) * on Friday July 01, 2005 @11:10AM (#12961486) Journal
        Let me add to that. We know that a G0 star has roughly the same mass as that of our Sun (*). Once you have some handle on its mass, you can do the following:

        (1) examine the wobble pattern of the main star,
        (2) then examine the effect of occultation (eclipse) by the planet (i.e., when the planet goes in front of the star, the brightness of the star decreases...which gives you a sense on how big this planet is with respect to the star's apparent disc),
        (3) then use Kepler's third law to derive the size of its orbit,

        Now you have two unique information: the orbital radius and apparent size of the planet. Unlike the earlier finding of the rocky planet, this study can provide you a quantitative estimate on how physically big this planet must be. And that turns out to be quite smallar than Saturn. You can also derive the mass of the planet from the scale of the wobble in the main star. Combining that with the physical size of the planet, you can derive the density of the planet.

        (*) Kepler's law goes like this:

        (2*pi/Period)^2 * (size)^3 = G * Mass

        where G = gravitational constant.

        If you plug in the Period (==2.87days) and size (0.046AU...circular logic, I know) of the planet, then you'd get the total mass of the star system to be about twice the mass of the Sun, roughly what we expect to be for a G0 main sequence star.

    • Re:weight (Score:5, Insightful)

      by PaSTE ( 88128 ) <{paste} {at} {mps.ohio-state.edu}> on Friday July 01, 2005 @11:03AM (#12961397) Homepage
      Surprisingly, astonomers actually "weigh" the planet by measuring either the planet's gravitational pull on the star, or the star's gravitational pull on the planet (by Newton's 3rd, they are equal). The idea is pretty simple:

      1) An object travelling in a circular (or eliptical) orbit requires a certain force toward the center of the focus of the orbit, called centripetal force [gsu.edu]. It is proportional to the product of the mass times the radius of the orbiting body, and inversely proportional to the square of the period of the orbit.

      2) Two massive objects will assert an attractive gravitational force [gsu.edu] on each other, proportional to the product of their masses, and inversely proportional to the square of the distance between the objects.

      All astonomers do is equate one force to another. Astronomers believe that they can calculate the mass of the star by observing the star's apparent brightness [gsu.edu], and looking at the star's spectrum to figure out what kind of star it is. Unfortunately, the observed brightness of a star is a function of its distance from Earth, and this measurement [gsu.edu] has a large degree of error for most stars.

      Next, astronomers look at how quickly the star "wobbles" due to the orbit of the planet. This gives a good measure of the period of the planet's rotation.

      The final step is to figure out how far the planet is from the star. After entering in all the data, you are left with the mass of the planet being a function of its distance from the star. If you apply some trickery in the form of Kepler's Laws [gsu.edu], you can see that the period and radius of an orbit are related.

      And that's it! Put all the pieces of the puzzle together, and you have an equation for the mass of the planet. If you are lucky, then the plain of the orbit is end-on when observed from Earth--this allows you to see how much of the star's light is blocked from the eclipsing planet, giving you some measure of the planet's size and composition.

    • Who cares if it's far away. I want to know how they measure the Earth's mass. I always figure they just turned a bathroom scale upside down.

      • Actually that only gives you the weight of the Earth (as caused by your gravitational attraction). In order to determine it's mass you must divide the weight of the Earth by the acceleration due to your own mass.

        So, if you know your mass without consulting the Earth's gravitational pull (which would require that you know the Earth's mass), you're set. If not, you must use an object of known mass to measure the Earth's mass, from which you can then calculate your own.

        And yet, I understand you were being

  • Fatal Attraction (Score:5, Funny)

    by Doc Ruby ( 173196 ) on Friday July 01, 2005 @10:35AM (#12961146) Homepage Journal
    Call me when they discover a giant planet, with a metallic core outside the planet. That's the armored base from which they keep sending us aliens like Ann Coulter and Tom Cruise. Then we just drop magnet-tipped nukes into space, and finally it's safe to watch TV again.

  • We're making progress... (Score:5, Interesting)

    by TripMaster Monkey ( 862126 ) * on Friday July 01, 2005 @10:36AM (#12961153)

    It's too bad that the only planets we can reliably locate at this time are the freaky-deeky ones that are too massive, too close to their primary, or are in orbits far too elliptical to give life a decent chance...each new system looks like a good example of how not to design a solar system capable of sustaining life.
    Hopefully, this will change when the interferometer [rl.ac.uk] goes up around 2015.
    • Isn't that more like "planets capable of hosting the kind of life we're used to?"
      • Life is order.... lots of it.

        Heat is, broadly speaking, disorder.

        While I, and a lot of scientists, would hate to go on record as saying something is flat out impossible, when your planet's heat gets high enough that all complex molecules are impossible, and any putative other type of order that might lead to life is jittered into unrecognizability in mere fractions of a second by heat, it's hard to imagine enough order on the right scale forming.

        So, even though I can't say 100% it's impossible, I'm prett
    • With a sample size of only nine (and those only studied close up with a handful of sensing devices) you've determined which planets are and are not suitable for life.
  • The beast planet is coming

  • Rockey'n'Roll (Score:5, Funny)

    by TheStonepedo ( 885845 ) on Friday July 01, 2005 @10:38AM (#12961183) Homepage Journal
    Heavy Metal planets are so Hard Core.

  • Core Architecture (Score:4, Funny)

    by Ray Radlein ( 711289 ) on Friday July 01, 2005 @10:41AM (#12961208) Homepage
    ...Scientists at Tom's Astrophysics Guide and Ars Astra estimate that this new massive core planet is still capable of outperforming the latest Intel dual core planets by up to 20% in the all-important Halo 2 benchmark.
  • metallic solid core inside

    A solid metallic core that's 70 times more dense than liquid rock? That's some kind of metal I'd like to know more about.

    Of course, maybe our planet is so light because its core is filled with million-year-old Martian war machines that are flimsy enough to be damaged by current weapons.

    Martians have journeyed millions of miles to attack a crane operator and his neighbors (and if they're not Martians, they journeyed a lot farther).

    --- Roger Ebert

    • Density = Mass / Volume. The core contains ~70 Earth masses, but there's no mention of the suspected size of the core. Quoth The Fine Article:
      The planet has about the same mass as Saturn, but a significantly smaller diameter.
      The planet has 0.36 times Jupiter mass and 0.72 times Jupiter size.
      So they're not saying that it's 70 times denser than the Earth, just that it's 70 times more massive.
  • "There are two competing theories for giant planet formation: planets form from fragmentation of a contracting dense cloud, or planets start as small rock-ice cores and grow as they gravitationally acquire additional mass. The large core of this planet couldn't have formed by the first model."

    You will have to excuse my ignorance here, but from my understanding, the accretion phase of the Nebular Theory explains that as things planets form as a collection of interstallar mass collecting and colliding in the
  • I wonder when planetary scientists will get a better picture of what's out there. The current observation techniques only pick up outrageously heavy planets with close orbits. Yes, I know this is inevitable given that the detection methods cue in on gravitational and occultation effects.

    Once we can detect an Earth-sized planet in a 1 AU orbit, we should get a much better idea of the actual prevalence of Earths and the fraction of solar systems "like ours."

  • In other news... (Score:5, Funny)

    by revery ( 456516 ) <<ten.2cac> <ta> <selrahc>> on Friday July 01, 2005 @10:44AM (#12961248) Homepage
    AMD vows to release planet with dual massive cores by end of '05. Intel responds by renegotiating contracts with its distributors.
  • I did not RTFA yet, but unless helioquake did a copy and paste from the FA then I'd suggest he, and editor Zonk (wtf good is an editor if he doesn't edit, ah?) go read this article [slashdot.org] as published on Slashdot. You know, that whole grammar thing? ;)
    • From what I read in that thread, the majority of slashdotters feel that grammar is useless and that the rules that do exist shouldn't be followed because "it's too hard to remember them all." Not that I agree with any of that. It sounds more like the ramblings of a bunch of lazy geeks. That being said, we should change the "editor" title around here to "filter" or "green-lighter," since that's all the "editors" seem to do...
    • No, grammar and spelling errors are mine, not editors (as I said in the other post).

      And I don't expect editors to proof-read, either.
      • And I don't expect editors to proof-read, either.

        So being an editor doesn't require editing?
        • I said *I* didn't expect editors to proof-read. If you do (and they don't edit for you), that's a problem between you and editors.
          • I understood you, and I'm not criticizing you. It just seems to me that it would help slashdot look more professional if editors checked for grammar and spelling, or at least readability. I would prefer it if we all came to expect this, but such expectations aren't currently justified. That's my point. If they actually did it regularly, you would expect it.

            • If they actually did it regularly, you would expect it.

              Readability, sure, but I'm not sure if I want CT to go through submissions and start correcting for spelling...

              I see your point, though. Nevertheless, I want to be responsible for my errors and to hold myself to a higher standard.

              [Maybe they ought to allow subscribers to proof-read?]
  • Astronomers know nothing about real estate:

    The planet is a rock. Luxury home owners wants a planet with a tropical paradise. It orbits the star in a weekend (two days). Luxury home owners want to go someplace for a weekend not be whipped around a star for the weekend. The planet is too hot by being too close to the star. Luxury home owners already have enough skin cancer.

    There's more money to be made in real estate than astronomy. But, sheesh... the astronomers need to find better properties.

  • So what does it mean? (Score:4, Interesting)

    by Dasher42 ( 514179 ) on Friday July 01, 2005 @10:48AM (#12961279)
    How much can we model to show what an environment like this is like? That planet's magnetosphere must be fierce. There must be a lot of side effects from that, both for it and any moons it may have.

  • I Have a Massive Core (Score:3, Funny)

    by repetty ( 260322 ) on Friday July 01, 2005 @10:57AM (#12961356) Homepage
    I have a massive core but no one ever writes about me.
  • http://en.wikipedia.org/wiki/Extrasolar_planets [wikipedia.org]

    The page talks about the history of detecting the planets and the various methods used.

  • Just like the rocky planet discovered earlier, the finding of this dense-core planet may lead to better understading of the formation of rockey planets in the Universe."

    I think this is a very interesting result to be sure, but I think I would like to see it confirmed. I am a little concerned that perhaps there may be something wrong with their analysis. I am familiar with this kind of work and there are a lot of places where errors can creep into the analysis and give spurious results. I hope that

    • A healthy skepticism is always a Good Thing, I think.

      I haven't read the actual journal article, but I'm sure that the paper is accepted by ApJ because error analysis is performed properly. Or so I hope.

      Anyway, what distinguishes this work from others (to me) is that many quantitative values (orbital period, the mass and radius of the planet, etc) are measured via observations. That doesn't happen very often in astronomy these days.

  • Makes you wonder... (Score:3, Funny)

    by d474 ( 695126 ) on Friday July 01, 2005 @11:14AM (#12961521)
    ...if they have crappy movies [imdb.com] about their core too. Poor bastards.
  • to strip mine *that*.

  • Rosette Stone? (Score:3, Informative)

    by EvilTwinSkippy ( 112490 ) <yoda@nOSpAM.etoyoc.com> on Friday July 01, 2005 @11:50AM (#12961900) Homepage Journal
    Dr. Concept to OR. Dr. Concept to OR.

    The concept of a "Rosetta Stone" in a generic discovery of signifigance. Rosetta Stone referes to a tablet that had a simultaneous translation of Heiroglyphics, Latin, and Greek, that allowed linguists to finally start cracking the secrets of the ancient Egyptian's written Language.

    This specimin that takes science in a new direction is more akin to "Mercury's Orbit."

  • Are they sure it's not just inhabited by geeks?
  • quick, get the star gate up and running so we can get there before the Gouauld

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