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Space Science

Mars Rock Found In Antarctica 51

Posted by timothy
from the it-was-lonely dept.
lousyd writes "Scientists with with ANSMET, the Antarctic Search for Meteorites, have found a meteorite in the Antarctic that apparently has come from Mars. Weighing in at 715.2 grams, the find has been confirmed by the National Museum of Natural History. The rock is a member of the 'nakhlite' set, and has been named MIL 03346. By having the real thing before them, this offers Mars researchers a reality check on the data coming back from the various probes currently on Mars."
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Mars Rock Found In Antarctica

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  • I'm curious... (Score:3, Interesting)

    by GedConk (778704) on Wednesday July 21, 2004 @03:06PM (#9762394)
    How can they be sure that it comes from Mars and not from an asteroid/comet/moon/whatever ?
    • Exactly. How?
      • Re:I'm curious... (Score:2, Insightful)

        by nlindstrom (244357)

        By having the real thing before them, this offers Mars researchers a reality check on the data coming back from the various probes currently on Mars.

        Bzzzzt! Wrong! You cannot compare A with B and use B to verify A if you are unable to independently verify B first. In other words, since we've yet to bring back any samples from Mars, we cannot know for certain that the Arctic rock is indeed Martian, and therefore cannot use it to sanity-check the data coming from Mars.

        It's a great case of a cyclic log

        • Re:I'm curious... (Score:1, Insightful)

          by Anonymous Coward
          It's not as simple as you think (pretend?). There are many facts in a single rock. A good geologist could probably tell you over a hundered things about a single rock. A thousand if you gave them a bunch of money to run some expensive tests. Not just one. For example, trapped gasses show the rock came from Mars because it matches the air sampled by probes. You can then use other facts about the rock to tell you more about rocks seen by probes on Mars.

          It's funny how people on Slashdot are so sure the

      • How can they be sure that it comes from Mars and not from an steroid/comet/moon/whatever ?

        Exactly. How?
        1. Turn rock over.
        2. Look for sticker that says "Made on Mars".
    • Re:I'm curious... (Score:5, Informative)

      by anim8 (109631) on Wednesday July 21, 2004 @03:27PM (#9762667)
      The Viking landers of the 70s identified the unique chemical compostion of Mars rocks. Likewise, the earth, moon and meteorites have their own unique characteristics.

      Read More [spacetoday.org]
      • You can reach the following with a Google "feeling lucky" search on "meteorite Vesta":
        http://www.solarviews.com/cap/meteor/vest amet.htm

        This describes some other meteorites that we know with good certainty come from the asteroid Vesta. The process is the same for knowing a meteorite came from Mars.
        • It's amazing to see how, even with such limited data, scientists are able to determine the origin of those rocks. Anyone know what to look for when searching meteorites ? My guess would be to look for an impact crater and check for unusual rocks but then again, IANAGeologist. I guess luck also plays a big role in that ;)
          • Re:I'm curious... (Score:1, Insightful)

            by Anonymous Coward
            Anyone know what to look for when searching meteorites ?

            Antarctica really is the best place to look for meteorites. There are huge areas where the only rocks are metoeorites (the rest is snow and ice). I'm sure it's on ANSMET's site some place, but I can't find it. Part of the East Antarctic Ice Sheet flows into the Transantarctic Mountaains. As the ice flows up the mountainside it sublimated by strong winds (nasty place). Any rocks in the ice are left just sitting on the surface. The dark rocks sta

            • If you take in the accounts of people who have gone to Antarctica to hunt meteorites (which they do every southern summer), you'll get an idea of how relatively easy it is to find them there.

              It's so easy, researchers have actually done it by robot. [spaceref.com]

          • A lot of meteorites will be small. Smaller than your fist. Maybe as big as a small marble. These won't leave craters. Other than that, I don't know how to hunt for them.
        • Re:I'm curious... (Score:3, Interesting)

          by b-baggins (610215)
          Why should the Oxygen isotopes be different in different parts of the solar system? Didn't we supposedly all coalesce out of the same cloud of stuff?
          • Same cloud, but it wasn't uniform. Each planet is different from each other, and from the Sun. They also came out of the same cloud.
          • People ask so many basic questions on slashdot. All these computer geeks know nothing about the world around them.

            Even on earth there is isotope partitioning. Lighter isotopes of water will evaporate preferentially (cause they're lighter). If we're in a glacial stage, these superlights will get deposited in glaciers, and leave the oceans with heavier isotopes of oxygen. Hence oxygen isotope dating... Look it up, the worls around us is very interesting.
    • Re:I'm curious... (Score:5, Informative)

      by Somegeek (624100) on Wednesday July 21, 2004 @04:22PM (#9763304)
      A really simple explanation from NASA:

      "Most martian meteorites are 1.3 billion years old or less, much younger than typical igneous meteorites from asteroids which are 4.5 billion years old. They also have higher contents of volatiles than igneous meteorites. The conclusive evidence that the SNC meteorites originated on Mars comes from the measurement of gases trapped in one meteorite's interior. The trapped gases match those that Viking measured in the martian atmosphere."

      For more detail:

      http://www-curator.jsc.nasa.gov/curator/antmet/mar smets/Text.htm [nasa.gov]

      • It is mostly argon, it reacts only under utterly insane conditions. If we took the same measurement on any planet with an atmopshere and found gas within a rock somewhere we could identify its origin, even if it came from another solar system once we have better scopes up.
  • by escher (3402)
    Mars rocks!

    Sorry... bad pun... no karma bonus... overuse of periods... running away now...
  • by anim8 (109631)
    The cool thing about Antarctica (no pun intended) is that if you see any rocks sitting on top of the ice they most likely came from outer space.

    I've heard that you are most likely to find them near the bases of mountain ranges where the swirling winds scours away the ice and snow better, revealing alien rocks and pebbles that have been covered for millenia.

    I'd guess there are tons of Martian rocks under the ice, perhaps some from Venus, lots of moon rocks ... and many more run-of-the-mill meteorites.
    • by missing000 (602285) on Wednesday July 21, 2004 @03:24PM (#9762633)
      Remember folks, launching stuff into a much higher orbit requires lots of energy.

      The reason Mars rocks get here is because they are intercepted on their way to the sun.
      • A comet or large asteroid could pull Venus' ejectae and send it into a higher or irregular orbit that could eventually cross paths with earth.
        • A comet or large asteroid could pull Venus' ejectae and send it into a higher or irregular orbit that could eventually cross paths with earth.

          Not to be mean, but pigs could fly too. Really, the chances of this are really quite slim. I don't have the data set to prove it, but I'd expect the probability of Venus originated meteorites in the once-in-a-billion-year range or so.

          Martian meteors on the other hand happen quite regularly. [space.com]

          In fact, there is a large list [meteorite.fr] of Martian matter found on ear

      • There is speculation that there are rocks on Mars which originated on Earth, but I've heard nothing about suspected Venus meteorites. Earth and Venus have roughly the same escape velocity, but that's not the problem so much as the atmosphere; it would take a much larger rock hitting Venus to deliver the same energy to the surface, and ejecta would have their energy drained by the CO2 soup and be far less likely to escape.
        • In theory, Venus ejecta might have been launched during the early "era of heavy bombardment", when the solar system was young and Venus had not yet undergone a "runaway greenhouse" and had a thin atmosphere.
          Both Earth and Venus were repeatedly hit by very large planetesimals, and would have ejected much material into space.

          Any venusian rocks that hit Earth would have been destroyed by erosion or tectonic activity long ago, but in theory there might be rocks from both the young Venus and the young Earth bur
      • by Urkki (668283)
        • Remember folks, launching stuff into a much higher orbit requires lots of energy.

          The reason Mars rocks get here is because they are intercepted on their way to the sun.

        Bzz. Wrong. Launching stuff to a much lower orbit also requires lots of energy. Basically the energy requirement is the same between two orbits, no matter wether you go from a lower to a higher orbit or the other way around. Quite obivious when you think about it, otherwise you could make perpetual motion machine, tapping the energy

        • Basically the energy requirement is the same between two orbits, no matter wether you go from a lower to a higher orbit or the other way around. Quite obivious when you think about it, otherwise you could make perpetual motion machine, tapping the energy difference...


          But how are we supposed to spin the Enterprise around the sun and travel through time then Mr Smarty Pants? ;-)

      • Well, actually, they are intercepted on their way to an orbit closer to the sun. To actually get to the sun from a planetary orbit requires quite a bit of delta-v.

        Interestingly, it actually takes more delta-v to get to the Sun from Earth (31.8 km/sec) that it does just to break away from the Earth (11.2 km/sec).

      • Oddly enough, putting things into lower orbits also requires energy. The Mars rock weren't necessarily on their way to the sun. All we really know about them is that Earth orbit came somewhere between the rocks' perihelions and aphelions.
      • There are two meteorites that are thought to have come from Venus, see here. [pair.com]
  • original article posting: "this Antarctic meteorite offers Mars researchers a reality check on the data coming back from the various probes currently on Mars."

    posting #9762667 [slashdot.org]: Q: "How can they be sure that it comes from Mars?" A: "The Viking landers of the 70s identified the unique chemical compostion of Mars rocks."

    Let me see . . . We know this meteorite is from Mars, because of evidence from space missions. And we know that we can trust the space-mission data, because it agrees with this mete
    • Well, I guess we're pretty sure they're not from Earth... And they are (I imagine) easy to re-examine, so measurement error sounds very unlikely.

      So, assuming that Mars probe results match the rocks, either

      a) both meteor and probe measurements are faulty, but by co-incidence or systematic error they match each others

      b1) rocks are not from mars, probe results are faulty but by incredible co-incidence look just like the Antarctica meteors from somewhere else

      b2) like b1, except probe results are not faulty
      • You're comments are all on-point. And the scientists are probably right.

        Nonetheless, it's STILL circular to say, "The meteorite is Martian, and so it confirms the telemetry from the probes" and "The telemetry from Mars missions confirms that the meteorite is Martian."

        There are many alternative (although unlikely) explanations.
        The point is this:
        the scientific community TYPICALLY demands a maddeningly-strict standard for "common-sense" hypotheses -- especially when there's an axe to grind, e.g. professiona

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