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Space Science

The Puzzle of Martian Meteorites 166

Posted by Hemos from the that-hideous-strength dept.
Alien54 writes "Recent analysis of several new Martian meteorites is confounding planetary scientists. To put it simply, an awful lot of the Martian meteorites are way too young. According to this thi s story found at Space.com, standard theories predict that most meteorites from Mars should be billions of years old. However, almost half of the known rocks from mars are under 200 million years old. These results open up a Pandora's box of questions. The discussions should be interesting."
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The Puzzle of Martian Meteorites More

The Puzzle of Martian Meteorites

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  • I think this proves that everything we know about space is potentially false...

  • Um... (Score:1)

    by pb ( 1020 )
    "Maybe they landed there later"...

    It'll be interesting to see if they can come up with anything better. ;)
    ---
    pb Reply or e-mail; don't vaguely moderate [ncsu.edu].
  • Shouldn't that be the Into_the_Silent_Planet department, Hemos?
  • Maybe I've been wrong about this whole religion thing. Maybe there is a God and he's messing with our minds!

  • Re:God (Score:1)

    by Pxtl ( 151020 )
    In that case, he seems to like circa 100-200 million years ago. His last gag was those wierd giant bird-lizard bones from around that time.
  • Thats quite a story. It could steer all known practices right out the window. I've always wondered how they can base assumptions of ages, without knowing if their calculations could be err'd in some way. Wouldn't it be cool if Mars had suddenly appeared just a couple of hundred million years ago. How do you explain that? Ok, Im rabmling, and I really dont have anything relevant to say except I can not wait to see how this develops. Im just waiting for some scientists to start backtracking to cover any misconceptions of carbon-dating that they might have. L8tr

  • The Secret's Out (Score:3)

    by dmccarty ( 152630 ) on Friday September 01, 2000 @09:18AM (#810315)
    A lot of those craters are our testament to NASA's attempt at a Martian lander.
    --
  • Comment removed based on user account deletion

  • Isn't Mars the closest planet to the asteroid belt? If so, and assuming that that occasionally an asteroid gets knocked into an eccentric orbit, might this not explain some aspects? Of course, that's dependent on whether there are young rocks in the belt. If there aren't, pardonez mon air chaud. ;)

    -TBHiX-
    Forgive Babelfish, for it knows not what it translates.

  • so certain are they? (Score:5)

    by jafac ( 1449 ) on Friday September 01, 2000 @09:34AM (#810318) Homepage
    The conclusion of the article says it all; that they need to send a lander to bring back samples from Mars as soon as possible.

    IANAEG or CC (Exo-Geologist or Cosmo-Chemist):
    I say this because until that happens, how can we be so sure that these rocks actually came from Mars? Yes, the chemistry is similar, to what we THINK Mars' chemistry is, based on our very limited (and no direct) observations, but if the planets, Mars included, formed by accretion of dust particles in space around the early Sun, then it stands to reason that maybe not ALL of the materials of similar Martian chemistry accreted to Mars. There could be any number of asteroids made of similar materials floating out there between Mars and Jupiter, and periodically colliding, getting melted, and sent Earthward. Sure, the stats may be against it, but I don't believe we really know all that much about the smaller residents of the asteroid belt.

    I'm not saying that these rocks are not from Mars, but I'm saying that maybe it's time to entertain alternative theories as to these rocks origins, because the data doesn't jibe.

    if it ain't broke, then fix it 'till it is!
  • It's pretty amazing what (us) scientists can extrapolate from limited data (ie. the radionuclide composition of the rocks in this case). Of course, there's a lot of data to back these extrapolations up. But they are assumptions after all. The best we can do with the lucky strikes that fall into our laps so to speak, allowing us to analyse the geology of another planet!

    Anyway, maybe Mars is geologically younger than we thought. Maybe this group of rocks is anomalous in some way. I guess we can only determine the difference if we stop pissing around and send somebody to Mars to see for themselves. The Mars Sample Return mission is a start, but it's extremely limited. Another "lucky strike" so to speak.

  • John Varley answer (Score:5)

    by Nidhogg ( 161640 ) <shr...thanatos@@@gmail...com> on Friday September 01, 2000 @09:51AM (#810320) Journal
    It took them 3 pages to say what John did in one sentence.

    Best scientific answer to date: It beats the shit outta me.

    The scientists are just in denial about the really obvious answer.

    The inhabitants of Mars are firing these little rocks at us just to mess with our heads.

    "Here Earth-scum! Take a gander at *foom* this one! Just quit bombing us with those damned probes!"

    Argh. Waaayyyy too much coffee today....

  • Regardless, I love the C.S. Lewis reference. His Space Trilogy was a great set of works by a great author!
  • Well -not being a geologist myself- if memory serves, C-14 dating is *only* really useful for biological structures. I'd assume they are using isotopes of other elements.

    j

  • I knew it!!! (Score:1)

    by Anonymous Coward
    Those Martian bastards have a rail gun flinging those things at us.

    I knew it... rotten Martian-Commie-Bastards....

  • Re:Unstable Isotopes (Score:3)

    by MrScience ( 126570 ) on Friday September 01, 2000 @09:55AM (#810324) Homepage
    I doubt it. There are many more isotopes, each with much greater half-lives than c14. Each is valid for a different range of years. For example, from http://www.talkorigins .org/faqs/faq-age-of-earth.html#howold [talkorigins.org]:
    The most direct means for calculating the Earth's age is a Pb/Pb isochron age, derived from samples of the Earth and meteorites. This involves measurement of three isotopes of lead (Pb-206, Pb-207, and either Pb-208 or Pb-204). A plot is constructed of Pb-206/Pb-204 versus Pb-207/Pb-204.

  • Bullseye! (Score:3)

    by Verteiron ( 224042 ) on Friday September 01, 2000 @09:55AM (#810325) Homepage
    Obviously the Martians were a race of giant creatures with immense strength and incredibly keen eyesight. Their primary sport was "Hit the Blue Dot", an odd pasttime which consisted of chucking rocks towards the earth. Any that managed to nail it, of course, got all the girls. Unfortunately, most of them were bad aims, as the Martian race obviously died out millions of years ago.

  • A test (Score:2)

    by romco ( 61131 )
    First you need to sent a probe to mars that
    launches a smaller probe to the surface
    from about 200mi above the surface. The little probe (launched from 200km) would slam into the
    martin surface....

    damn it...they already tried that
  • Wait... Dare I say it? Maybe he died 100-200 million years ago?
  • "err'd"

    What is this word?
  • This is perhaps the best argument yet for pushing ahead aggressively with manned missions to Mars. It shows that we can learn only so much about an object by looking at it with telescopes. Even when that object is extemely close by, all things considered. Satellites and unmanned landings have clearly not given us the information we desire.

    If we want to unlock Mars' secrets, we've got to get there ourselves.
  • why yes, carbon-14 can only be used accurately for that long because of it's short half-life, but there are many other unstable isotopes that have been used to date materials - isotopes with much longer half-lifes. some include:

    potassium->argon
    argon->argon
    rubidium->strontium

    etc etc.
    these isotopes let you accurately measure the date of materials way beyond that of carbon-14 dating.

  • I can see it now. "Well, God only made Earth look really old. He didn't spend as much effort making Mars look old. Really, they're both only 6000 years old and this hundred-million years is a facade made to trap the satanic atheists."

    (Modified only slightly from an actual IRC quote).

    --
    Ben Kosse

  • Did anybody consider that maybe the Martians have only recently (in geologic time) evolved to the point that they could build machines powerful enough to lob the darned things at us?

    It's probably enough fun to keep them pretty busy nowadays - I imagine with Martian weather things could otherwise be a little monotonous.

    - -Josh Turiel

  • Re:so certain are they? (Score:3)

    by crumley ( 12964 ) on Friday September 01, 2000 @09:59AM (#810333) Homepage Journal
    Yes, the chemistry is similar, to what we THINK Mars' chemistry is, based on our very limited (and
    no direct) observations

    Wrong, the Viking spacecraft made direct observations of the Martian atmosphere, and its these observations that are the basis of the claim that these meteorites are Martian in origin. The proof is really quite convincing. Take a look at some of the links available here. [houstonspacesociety.org]

    To me it seems pretty clear that the meteorites are Martian, whether we know the geologic history of Mars that well seems to be a little bit more in doubt.

  • that the process of knocking rocks off of Mars into space and their subsequent reentry thru the earth atmosphere would seriously disrupt the ability to date them by the isotope decay methods described. Therefore, a robotic Mars mission to bring samples back is justified. M&M's sold separately.
  • The reason that at least some of these rocks are thought to be from Mars is that bubbles in the the impact glass (i.e glass formed during the impact that ejected them from Mars) contain gasses whose isotopic rations could only be found in the Martian atmosphere. Others are believed to originate on Mars because the chemistry of the rocks indicate extensive geological processing that could have only occurred on a relative large (and wet) planet. Since these rocks have O isotope ratios that are unlike Earth's and it is really hard to get rocks up the gravity well from Venus, Mars is the only choice.

  • Interesting mind-game (Score:4)

    by rho ( 6063 ) on Friday September 01, 2000 @10:02AM (#810336) Journal

    Had a conversation with my brother about something similar to this. The topic basically was, "The universe isn't as old as scientists believe". The posit: the universe (and all physical actions) are slowing down over time.

    To explain: we know the age of X because of carbon dating. Carbon dating assumes that radioactive decay is a constant. What if, in the past, things happened much faster? Light travelled faster, radioactive isotopes decayed faster, etc. And as time went on, the physical properties assumed to be constant slowed down.

    I dunno -- I know my VISA bill grows faster in the present than in the past, but VISA physics defies all rational thought. But, it's an interesting idea.

  • I think i have finnaly figured out what NASA is up to, a long time ago the indigineous intelligent peoples of mars was bombarding us with meteors, and after 200 million years we are finnaly returning fire with billion dollar satalites and ground survey equipment!

    Kick thier martian green ass NASA!

  • Eh... (Score:1)

    by cronio ( 13526 )
    I guess those meteorites that landed in my backyard that I originally thought were from Mars until I dated them to 190M years ago in my basement could actually be from Mars.

    Cool.


    Not reading .sig
  • The article mentions "weakly radioactive" isotopes. I was presuming that they were talking about potassium40 argon40 ratio. I don't know what the horizon is on this measurement.

    C-14 is only useful for dating PLANT material or animals that eat (directly or indirectly) recent plants.

  • Anyone who watched Mission to Mars will doubtless realize that these recent meteorites were generated whent he martian emigration fleet blasted off.
    I mean, come one. It's so obvious.

    Disclaimer: I saw that on a transatlantic flight while suffering jetlag and sleep deprivation. i was bound to get some funny ideas, okay?
    -J
  • After searching for "dating isotopes" and worrying about implications for my romantic life, I found this [129.252.37.27] list of half lives:
    • Carbon-14: 5730 years
    • Uranium-235: 704 million years
    • Potassium-40: 1.3 billion years
    • Uranium-238: 4.5 billion years
    • Thorium-232: 14 billion years
    • Rubidium-87: 48.8 billion years
    So if some other isotopes are present, they could easily do the dating.
  • How do you know how much of the original isotope you started out with?

    Also, how are half-lifes measured to millions of years? We've only known about this stuff for about 100 years...

  • The geology of asteroid rocks is much different, than the geology of Mars or the Earth. Originally it was thought that these Martian meteorites might be from asteroids or other small bodies, but that option was eliminated. See the link I posted elsewhere in this story.
  • The article took as a given that we know absolutely whether or not a particular meteor came from Mars. Can someone point me to an article saying how we know this?

    What distinguishes a rock from Mars from a rock from earth? A chunk of magma congealing underground isn't going to have much interaction with the atmosphere. What else is consistently different on mars from any other solar system body?

  • If you are worried about the assumptions about their age, what about the assumption that the meteorites come from Mars?

    Bruce

  • Article: "Einstein Explains Theory of Relativity"

    Slashdotter (knows nothing, but states the irrelevent obvious): "When is Einstein going to learn that F = MA??"

    Moderator: Ooooohhhh Aaaaahhhhh Mark this as insightful!


    --

  • Nope. Having them knocked off the surface of Mars by metorites etc. may indeed heat the rocks up to extreme temperatures and put them under a fair amount of stress. You don't get alterations to radioisotopes from that sort of processs though since that would be a nuclear rather than chemical chagne. Some elements may be boiled off more than others, but this will affect all the radioisotopes of that element equally (well not quite, but the diffierence isn't going to be significant). The tests look at the ratios of various isotopes and so will not be affected by this process either.

    A sample return mission is justified for other reasons though. You destroy a lot of other information in the process of ejecting fragments of planet by metor strike!

  • Please see google [google.com] and learn for yourself.

    I think you will find it fascinating.

  • No matter how much we think we know about dating things, it's still guesswork. Unless you or the person claiming to know the age were there when the object was "created" (really just matter being converted, we don't "create" any matter), you/they can only guess at its age. We can guess fairly accurately at relatively recent things, but we can't even say with full certainty what the C14 level, or any other age determining factor, was 1000 years ago, let alone exponetially higher ages.

    We can't guess right all the time, so don't expect all guesses (hypotheses even) to be right, and don't be so surprised when they're wrong. :)
  • Damn those guys who built the sets to the Britney Spears video. Leaving their fake Martian rocks all over the planet...

    On a more serious note, maybe we've just found the younger rocks, and the older ones are still lying around.
  • erm?
    Why is your bird decapitated?



    <O O&gt
    ( \/ )
    X X
  • I really don't think it's funny to joke about extinct races.

  • Something interesting to add to the recipe.. (Score:3)

    by Bowie J. Poag ( 16898 ) on Friday September 01, 2000 @10:16AM (#810353) Homepage


    About a year ago I was on campus watching a lecture being given by one of the Profs from the Aerospace and Mechanical Engineering department here at the U... (U of A is a big school for space-sorta stuff) ..They were demonstrating a film prepared by the department about how the moon may have been formed. We've got big mongo array of Cray/SGI supers here on campus chugging on this sort of stuff around the clock, its kinda neet -- But anyway, the animation they prepared on these supercomputers shows a pretty big sized planitesimal smashing into the earth during its early years, and tearing a hunk of it off that eventually recollected and solidified, becoming our own moon. Everything in the simulation matched... They even got the moon resulting from the collision to have the same rotational period so one side is always facing the earth.

    And now, why this is relevant:

    There was some speculation that very early/primitive forms of life may have existed on Earth during the time this collision occured. The debris from the collision could very well have contaminated the rest of the solar system with life, including Mars. ALH84001 may just be the ancestor of a hunk of material that came off of earth, made it to mars, then got blown back here. Weird, eh? :)

    By the way, 1998-2000 PROPAGANDA Image Archive CDs are now available. Click the "Enjoy!" link below...and enjoy. :)

    Bowie J. Poag
  • keep up the good work
    heres a replacment


    <O
    ( \
    X
    8===D

  • Re:God (Score:1)

    by Anonymous Coward
    No, I think he's still around. Who else but a greatly benevolent deity would bestow upon us the ultimate prize, The Slashdot Cruiser? How could you overlook the intervention of jehovah in the gifting of such a magnificent chariot? I can picture Jesus and the apostles driving that one about, solving mysteries and shit.
    "And lo, blessed are the trolls, for they shall travel in comfort and style." Signal 11, 3:14
  • my penis bird he was getting a little too horny. i had to cut his head off.


    ( \
    X

  • I assume they mean carbon-14?

    that is beacuse you are an idiot.

    When are these people going to learn that you cannot find the age of an object using that method?!

    probably about the same time you realize there are other radioactive elements, if that ever happens.
  • Bullshit. If you take your thinking to the logical outcome, you are saying, unless you have direct proof that something is there, it cannot be. Okay, I guess you don't believe in atoms and science on a microscopic scale cause you can't see it with your own eyes.

    The truth is that every day we use science that is based upon things that we can't necessarily measure directly or see directly. You are calling calculations and extrapolations based upon a sound theory guesses. If you follow that path of reasoning, you must throw everything else out.

    There conclusions may be wrong, but I would not doubt the dating itself. It is a common and sound technique, not a guess.
  • Did you have to break his legs too?
    You're in danger of having your Penis Bird License revoked...



    <O O&gt
    ( \/ )
    X X

  • Re:Interesting mind-game (Score:4)

    by (void*) ( 113680 ) on Friday September 01, 2000 @10:26AM (#810360)
    No. There is no such universal scaling constant. It takes more than more one number to describe physics. Let me try to give you an idea of what I mean.

    Suppose you doubled everything in size. You are two times large. Since everything doubles in size, it must mean that you can't tell the difference between now and before right? Wrong.

    Since everything is doubled, the force of gravitation between say two planets would drop (increased distance). Nevermind, let's keep the force the same you say. So we have to increase the masses between any two objects (F = GMm/r^2 - remeber?). But having increased mass, do we now keep the forces between charges the same? If you do, then the charge to mass ratio of the elctrons and protons will change - this effect is measureable. Lots of physics - emission spectra of atoms and molecules would be different as a result. We might not even be around to observe this.

    That was just playing around with distance. It does not work for time as well. Some combination of the two? Not even that.

    In other words, if something was different in the past, we should be able to see that effect physcially as we look backword in time at the stars. The people who are selling this idea are not thinking broadly enough about the entirety of physical phenomena.

  • In a nutshell: "Martian meteorites may not be from Mars, but from the same source Mars comes from."

    Ok... so it's some kind of Open Source thing... ;-)

    So when was this theoretical big comet or meteor which may have wiped out the dinosaurs? About that time, perhaps?

    Personally, I think it's all explained some sort of intersteller billards shot, the cue ball probably smacked into the Sun and we'll have a heck of a time retrieving it for the next shot. :-)

    Vote [dragonswest.com] Naked 2000
  • Dear moderator, In what way is this post insightful? Please go to your preferences and change your options to 'do not wish to moderate'.

    -Pete

  • What I'm saying is there's a lot of assumptions being made.

    For example, with potassium-argon dating, how do we:

    • know that potassium-40's half-life is 1.3 billion years? Even over 10 years, that's a part-per-billion experiment.
    • know that there wasn't argon trapped in the rock along with the potassium in the first place?
    Some good scientists admit these assumptions up front, for example http://www.icr.org/research/sa/sa-r03.htm [icr.org] clearly says:
    The model age method assumes no radiogenic 40Ar was present when diabase and lavas cooled to form rocks.
  • Two things:

    C-14 dating is only for things that LIVED on Earth.
    C-14 dating is only for things that lived on EARTH.
  • somehow that's just not as funny coming from you as it was from Meept.

    if it ain't broke, then fix it 'till it is!
  • True. But by measuring what portion of it decays in 100 years, we can extrapolate the half life.

    75% decayed => half life is 50 years
    50% decayed => half life is 100 years
    25% decayed => half life is 241 years
    10% decayed => half life is 658 years
    1% decayed => half life is 6897 years
    .1% decayed => half life is 69280 years

    and so on.



    --
  • damn it...they already tried that


    Heh heh...

    Look... If we built this large badger...

  • Re:Mission to Mars (Score:2)

    by Anonymous Coward
    If we want to unlock Mars' secrets, we've got to get there ourselves.

    Or we could just blow it up and study the debris that hits earth. It'll save us a trip.

  • You must be from Kansas.
  • if the dating of the rock is done based on the last time the rock crystalized, it could have been a medium-sized asteroid, (the inner rocks having been protected from long-term exposure to cosmic rays), with a chemical make-up similar to that of Mars, (being from the same region of the solar system, having accreted from the same mix of dust and stuff), having been involved in a collision that melted it, thereby resetting it's "age", then fragments headed towards Earth.

    Oh, and I Am Not A Scientist either, but I play one in make-believe with my kids. I'm the mad kind that tries to take over the world with an army of mind-controlled penguins, or giant robots.

    if it ain't broke, then fix it 'till it is!
  • I'm saying if you don't have 100% proof, you can't be 100% sure. If you have 99% proof, then what happens if it's the 1% that makes the difference?

    We can never been 100% sure of even the things we think we see, so don't be so upset if the popularily accepted hypothesis A is questioned by supposed fact B. An educated guess is a very good guess and may be used almost like fact, but is still a guess and as such we must not be so upset when the "fact" is questioned and perhaps even changed.

  • First you need to sent a probe to mars that launches a smaller probe to the surface from about 200mi above the surface. The little probe (launched from 200km) would slam into the martin surface....

    damn it...they already tried that

    Heh heh...

    "Look... If we build this large wooden Badger..."
  • Well, it would appear that I have been 0wn3d :(
    Kudos, to you, good sir. Your powers are mighty and your spelling better even than that of the Slashdot editors.
    Thank you for showing me the error of my ways.
    Alas, the patent system is so fucked up that even the concept of 'Hooha Man' is no longer in the public domain.
    I realise now that I was foolish to think that I could get away with using this name. I reckoned without the unstoppable force that is the Anonymous Coward horde. Fair play, the game is up.


    <O O&gt
    ( \/ )
    X X
  • Yes well...

    Actually, there's a pretty easy way to test that theory. Measure something (speed of light, decay, whatever) and then measure it again in a few weeks or so. If there's no difference, you're set. We have very accurate machines now a days. (Very precise actually, I read about an experiment where two clocks were used, one was on a jet plain (or something) and the other sat on the ground. The clocks were accurate enough to notice the change in time itself on the airplane because it was moving slightly closer to the speed of light (or maybe something about the gravity of earth, I can't remember, exactly)

    But then, one might say that the machines themselves are being slowed down as well, in essence, time itself is slowing. But if that were the case, then it wouldn't matter everything would still be going at the same speed.

    Or you might say that the things stopped slowing down, in this case, but that would be no different then saying the world popped into reality a second ago, with everything set into motion, there is no way to prove that it didn't happen...

    In other words, science is only interested in stuff that you can theoretically prove didn't happen, if you can't, then it simply doesn't matter. The only information worth having is the stuff that has some effect on reality, and the world around us.
  • He may be a hooaha and so are you

    (__)
    (oo)m00!
    /--------\/
    *o|||
    ||----||
    ooo^^^
  • Hmmm... Here's a thought:

    From the story:

    The age of the Martian surface has been calculated by examining the number of craters on Mars, Mittlefehldt explained. The oldest surfaces would have been exposed to meteorite impacts from space for the longest time, and thus would have the most craters on them. Young surfaces would be relatively free of craters.

    Using the current understanding of crater density, a maximum of 15 percent of the Martian surface could be as young as 175 million years old, Mittlefehldt said. Even getting that high of a percentage is really stretching the model, he said. It simply doesn't make sense that half the meteorites from Mars and half the big impact events that sent them to Earth just happened to hit the 15 percent of the surface that is young, he said.


    This method of determining the surface age of Mars seems to assume that the meteorite strikes occur at consistent intervals. Therefore, the older the surface, the more impact craters. However, what if there was some reason that a surface which is relatively new (say, 175 million years old) has a much higher density of crater impacts for some reason? Here's what I think: There were very high levels of volcanic activity when these meteorites we're finding were formed. Soon after, one or several large impacts caused a great deal of this newly formed rock to be thrown into space. Several bits made it to earth where we can now puzzle over them, but more importantly, most fell back to Mars, causing heavy cratering over most of the surface.

    Thus, the surface of Mars has seen recent volcanic activity, but still shows heavy cratering because the same impact that sent the meteorites to us also sent up large rocks that came back down to form many new impact craters; many more than would be normally be formed in that time span.

    But, IANAMG (Martian Geologist). Is any one here who is know if this would work?

  • Yeah! Bring back the 50 yard dash!

    -Pete

  • In a way, you are correct. Carbon dating is not a realistic way of testing these "martian" stones. But, other means of dating are even more creditable than carbon.

    Carbon will only work for something like 100,000 years. Before the carbon has halflifed to much.

    perhaps something else, that man haven't considered. What if the origins of the rocks aren't mars. they say that they are, based around the fact that they have similar properties. But perhaps the properties that they show, are more common than we believe. Maybe we should send a craft to phebos, or demos (doom rulez!) and check what the make up of those rocks are. Perhaps when we took a sample from mars, to test, it happened to be a metorite similar to what we are seeing.

  • Oh come on, do you really think that people haven't (and aren't still) going over the case for these meteorites being from Mars? Extraordinary claims require extraordinary proof, and all of that.

    Anyway, it seems pretty clear that the meteorites are from Mars, though it is slightly less clear for the meteorite which they claimed might have life (that's a hypothesis that is far from proven) as this article [planetarymysteries.com] explains.

    Also, here's a really nice bibliography [nasa.gov] on Martian Meteorites for those looking for some light reading.

  • But with dating using these techniques, it is not generally a binary change in the "guesswork", there are error bars attached to any estimate. They are small I believe.

    There is of course the possibility that one of the underlying assumptions used in the techniques are wrong...but those assumptions (and these techniques) have held for a number of years. That doesn't mean they are not still assumptions, it just means that we can feel pretty warm and fuzzy about just like we can feel relatively warm and fuzzy with encryption techniques that have withstood rigorous peer review and testing.
  • There's a fundamental flaw in our age measuring process???? Could we simply be measuring their ages incorrectly?

  • ...this hardly deserves "Insightful". It's pretty content-free. Note the needless repetition of ideas, malapropisms, and use of filler such as "ever-expanding rapid rate".

    Read carefully. The poster could have said the same thing in much less space:

    We need to think about how space exploration (in particular, the Mars Meteorites) will change our lives, because it is very controversial. Some people introduce new ideas, while others hold on to existing (possibly flawed) ideas.

    Which of them is right?

    The latter group says that the meteorites threaten our existing theories in ways we are not prepared to handle. Maybe the meteorites should be forgotten.

    The former group says that if we study them, we will learn new things. Then scientists will get new tools that only the "elite" formerly posessed.

    Maybe both groups are right. The new ideas might make us uncomfortable, but they could be better than the old ones.

    What will happen? We don't know yet, execept that people will argue about it a lot.

    I wouldn't accept this from a student, let alone give it anything better than a "D".

  • Proof was needed? Everything we know about everything is potentially false.

    -Pete

  • I have two theories:
    1) The dating technique(sp) that they use to date the rocks, which carefully measures how much various unstable isotopes have decayed away, does not take into account interplanetary phenomenon like various cosmic rays and different forms of radiation....

    or

    2) Mars, 175 to 180 million years ago supported a thriving civilization of technologically advanced peoples. These peoples were unable to stop a large meteor from impacting their planet....The meteor did impact the planet, spewing Mars debri into the solar system and ending life on Mars...

    Or maybe I just need some sleep....

  • go away (Score:1)

    by Anonymous Coward
    I'm trying to troll here, resoned response not welcome.
  • Actually, the entire universe sprang into being fully formed about two and a half minutes ago. All the memories you think you have came into existance at the same time.
  • I'm not supposed to say this in public, but since it's slashdot, it'll be written off as blatherings...
    Humanity started on Mars billions of years ago.
    They seeded Earth as a new place to live, as they wasted their natural resources and destroyed their own planet.
    They also seeded Earth with low-level lifeforms whom they could use as beasts-of-burden and slave labor.
    All those crop circles and such you hear about today are people who still have this Mars programming in their subconscious and are making landing sites for their masters.- whom no longer exist
    And it's also the reason for the various odd land formations, like the Nazca works in South America.
    However, something went horribly wrong on Mars before the seeding and transplanting was complete...likely some kinda war which wiped out all natural life on that planet. We're still looking into that.
    Thus, earth was left to develop on it's own- and look where we are today! Not too bad...
    The thing we need to worry about is when the beings who seeded Mars come back to look in on their experiment. Will they know we're related? Or an aberration?
    Wait and see, young ones, wait and see.
    ---
  • I'll read that link when I'm done reading all the Penis_Bird posts, but post #41 seems to sum things up pretty nicely - or at least does serious harm to my Asteroid theory.

    But the fact is, that even with Viking, we don't have DIRECT observation. No human being has ever touched or seen an actual Mars rock that we're sure came from Mars, with the exception of these meteorites, so we can't be sure that that is actually where they came from.

    Bottom line is - either Mars' surface is younger than we thought; which really fucks the hell out a lot of assumptions we have about our solar system, which are really foundational, OR our isotope dating system is WAY off, which also fucks with a lot of assumptions which are really foundational, to more than just the origins of our solar system, OR something happened to these rocks in-transit that totally messed with the isotope ratios in a way we have no scientific way of modelling, (I'm picturing prankster-aliens with a particle accelerator) OR, these rocks did not come from Mars. Occam's Razor suggests #4 is most likely, IMHO.

    if it ain't broke, then fix it 'till it is!
  • This may not be as easy as it seems, as the above test supposes Euclidean
    space. If, per chance, the universe is more condusive to Reichenbach's
    theorems, then there is no constant to test anything against properly (by
    those standards), only perceived constants. Question: If light increased
    its speed when trapped in the gravitational mass of a black hole, would
    "light speed" still be a constant? I personally believe light to be the
    same type of radiation as audio vibrations. Different frequencies and
    amplitudes means different speeds of travel, and different maximum TTL
    (for lack of a better term at the moment).

    Wildly speculative consideration: An atomic bomb is, for all intensive
    purposes, two uranium rocks slamming together at extremely high speed (over
    simplified). If a collision of this nature of these elements can cause
    a reaction on the atomic level, then wouldn't it also stand to reason
    that less radioactive (or even stable) elements could, under an extremely
    high-speed collision (approaching average light speed?) cause a reaction
    on the atomic level?
  • These meteorites are basaltic, which means that Sr/Rb, K/Ar, or Ar/Ar age dating was probably used. The basic premise for something like Sr-Rb dating of igneous goes something like this.

    Take a homogenous magma composed of some Sr an Rb. Now let it cool thus forming various minerals such as plagioclase, pyroxene, and olivine.

    Now: Rb87 decays to Sr87. Sr86 is stable and is not a by-product of the radioactive decay of another isotope. The number of Sr87 atoms in a mineral is given by

    Sr87 = (Sr87)o + Rb87 * ( exp(at) - 1 )

    where (Sr87)o = original amount of Sr87 at the time of crystalization, Rb87 = current amount Rb, a=decay constant, t=time since crystalization. Now divide by the amount of Sr86.

    Sr87/Sr86 = (Sr87/Sr86)o + Rb87/Sr86 * ( exp(at) - 1 )

    If the initial ratio of Sr87/Sr86 is uniform throughout the rock at the time of crystalization (as it turns out, this is a good assumption), then this the above equation is the equation of a straight line where (exp(at)-1) is the slope, and (Sr87/Sr86)o is the y intercept.

    Now measure the various isotopic ratios from various minerals in different parts of the rock. The decay rate is known from the results of laboratory measurements. Solve for t.

  • Well, I guess we have different definitions of direct. By your definition electrons have never been directly observed either. Sure, Viking was a long way and it was '70's tech, but the isotope ratio match really well.

    As for what theories are likely in error, we recently gotten a lot of new info about Mars which has put a lot of its geology in question. We still don't know a lot of really basic things about Martian (and Venusian) geology, especially when it comes to formation history and age. And much of aging is based on cratering history, which has a lot of assumptions going into it.

    Heck, the theories to explain the formation of planets in the solar system are still really wobbly. Anyway, I think the fact that these meteorites are from Mars is on a lot more solid footing than much of planetary science.

  • Re:Dear Lord! (Score:3)

    by rho ( 6063 ) on Friday September 01, 2000 @11:31AM (#810400) Journal
    I'd laugh at your ignorance, but you're not the only one who's gone off about carbon dating in this thread.

    Well, I'm not really talking about carbon dating, but using it as an example for the whole of the idea. If it makes you feel better, replace "carbon dating" with "speed of light".

    And you are allowed to laugh at my ignorance. In my family, I'm one of the ones holding the bottom of the intelligence ladder. I've got an electrical engineer father, a math teacher mother, two mechanical engineering uncles, a cousin with a 4.0 in Aerospace engineering and my brother who is finishing a computational engineering degree. I'm the creative one (euphamism for "well, at least he GOT a degree...").

    I don't present it as gospel, but it is a philosophical argument that occurs in the scientific community (at least, the parts that I'm familiar with). It's called Uniformitarianism, or something similar. All things continue as they always have.

    I find it sad, though, that you outright dismiss the idea. Everything I've ever read or heard from really smart people mentions that they don't believe that they know everything, or indeed a lot about anything. The quest for knowledge stops as soon as you believe that you know all there is to know.

    I don't claim to know the answer. I don't even claim there is an answer. I just claim that I find it an interesting thing to talk and think about. It gives a different perspective on things, which may lead to a greater understanding of the problem, just as it may lead to a two hour wanking session. I make no guarantee or warranty.

    Anyway, I appreciate the links. They've got good info, and I learned something new, which is cool. However, I will always keep in mind all of the things that science KNEW was true, until somebody discovered something else that discounted the earlier theory, which led to new things that science now KNEW was true... ad infinitum. They are working theories -- and good ones, I might add -- but only theories.

  • That maybe these rocks are all the result of a large Mars meteor strike 175 million years ago?

    The meteor struck, blasted a crapload of molten rock to escape velocity, where it cooled and solidified, resetting this isotope 'clock'.

    -josh

  • How do we know the half-life of $element

    Take a kilo of $element (measured to an accuracy of 1 ppm): Given the atomic weight of $element, you know how many atoms of $element you have (to an accuracy of 1 ppm). You know that when $element decays it emits N $particles: so set up a particle counter and count how many $particles are emitted in $time: This give you the number of atoms that decay per unit time for that many atoms. You derive the decay rate of $element from that.

    Given that $element1 decays into $element2, how do we know that there wasn't any $element2 in the mix to start with?

    In the cases that are used, the decay product of $element1 isn't any old isotope of $element2, but an isotope that is not produced by any other form of decay. Therefor, you know that every atom of $element2<isotope-x> was produced by the decay of an atom of $element1.
  • I like your explaination of that. It is logical and seems to hold merit. Now, they claim that the rocks came to earth at different times (and spent different amounts of time in space on the way) so they couldn't have come from the same 'initial impact'.

    To this I say, there was the initial impact (followed by your explaination above for the multiple craters). Then, there was a great out-pouring of many rocks into space. The earth caught a few of them on their way out from Mars (on their trip 'away' from the sun) and the others circled in various 'shaky orbits'(elliptical) until they fell to other planets, fell to Earth (some on their trip back 'towards' the sun), fell into the sun itself, or even fell back to Mars. Wouldn't that explain the various amounts of time in space, plus the fact that they arrived on Earth at various times?

    Or am I missing something obvious that the article didn't mention? My feeling on this is that the 'Martian Geologists' are too close to the situation and are trying to look for the most complex and 'other worldly' type of explaination. Much like computer technicians get frustrated as hell because they can't figure something out (and they fight it and fight it looking at all of these complex possibilities), then some nearly computer illiterate person says, "hey, what about this?" and the techy smacks himself in the head for being a moron.

    I say we 'open source' science, and put them (the scietists) on usenet and mailing lists that are easily accessible. Sure, they would get four hundred times as many useless messages as they got good messages, but I think it would be worth it if they got a few 'simple people's' explainations.
  • So we have to increase the masses between any two objects (F = GMm/r^2 - remeber?)

    Ummm.... no. Jessica Riley was missing a button on her blouse the day my physics teacher taught me that. That's my story, and I'm sticking to it.

    In other words, if something was different in the past, we should be able to see that effect physcially as we look backword in time at the stars.

    Good point. I was going to say that since the speed of light was faster In The Beginning, then the stars that we study would not be the same as they are today... until I realized that was your point all along. FWIW, I was taking the position of You're Full Of Shit with my brother, and you just gave me another talking point.

    Now, let me bring up a point. (First, a disclaimer -- based on many discussions with a lot of smart people, that I'm an idiot is a given. Bear with me...) Perhaps we do see the effects of a Universe that's winding down in the stars, but we are interpreting the effects incorrectly? Or, more importantly, the assumptions we make in regards to Uniformitarianism (as I believe the philosophy to be called -- all things continue as they did in the past) color the observations made.

    An example: an astronomer observes a star emitting boogie-rays. Based on Horace McGillicutty's studies of boogie-rays, the astronomer knows that this star is in the last stages of the Boogie-Woogie Blues. This is a fair assumption based on available evidence. However, McGillicutty's study is based on the assumption that the Tip == 15%. The next week, Malcolm Strumple releases a paper that posits the Tip == the inverse of the square of how many times the waiter has to return the food to get your order correct. Suddenly, the star isn't suffering from the BW Blues, but from something else that we don't have a name for yet.

    (okay, it's trite. Think of it as pseudo-code...)

    Now comes the fun part -- because Strumple's paper on the new Tip calculation forces a lot of people who have fervently believed something to rethink their positions, it makes them unhappy. Very unhappy. Not much different from a Ford person calling a Chevy person a short-dicked asshole, only with bigger words. (who says science isn't fun?)

    I guess my point is that it's not good to lock down your thinking on something that we have no way of knowing absolutely-for-sure-no-doubt. It may be a great theory, but it's still a theory.

  • The first book of the trilogy is "Out of the Silent Planet." The Silent Planet is Earth. Or at least what the Malacandrans refer to earth as. They call Earth "The Silent Planet" because its ruling eldila have become rebellious against Maleldil, the governing Spirit of the universe, who Ransom presumes to be the same as Jesus. Mars, incidentally, is Malacandra.
    ----
  • The reason that at least some of these rocks are thought to be from Mars is that bubbles in the the impact glass (i.e glass formed during the impact that ejected them from Mars) contain gasses whose isotopic rations could only be found in the Martian atmosphere. Others are believed to originate on Mars because the chemistry of the rocks indicate extensive geological processing that could have only occurred on a relative large (and wet) planet. Since these rocks have O isotope ratios that are unlike Earth's and it is really hard to get rocks up the gravity well from Venus, Mars is the only choice.


    I've often wondered about this. Why would a rock that fits that description automatically be from Mars? Are the rocks that are floating around in our solar system only from our solar system?

    I always laugh when thinking about how wrong scientists were about Jupiter (or was it Saturn?) when they dropped that probe into it's atmosphere. I get the feeling a lot of the times that they're just playing with high tech equipment, allowed to make whatever "statement of fact" they feel like (with absolutely no consequence to the correctness of it), and change it whenever it suites them to do so. Plus they get paid to do this! I think I picked the wrong profession...

    Granted this is all a scientific process, but given past success with these types of "predictions", I am not convinced that these "martian" meteorites are actually from mars.
  • The above paraphrased: Yeah, I was wrong, but let me argue an unrelated point in an attempt not to look like a total ass.

  • Yes, I am sure that people are still going over that. It's something we should take note of in popular discussions like Slashdot: we have good reason to think that they are from Mars, but no proof. The case for the lunar ones is a lot more sure.

    Thanks

    Bruce

  • This sounds like additional support for Dr. Tom Van Flandern's Exploded Planet Hypothesis [metaresearch.org].
  • I agree - great ref to C.S.Lewis' Space trilogy. The books are, you know, written by a Christian Fundamentalist. While Clive (hist first name) would enjoy the origin of the rocks (from Mars, meteors spun 'round Mars to knock us on our noggins, etc) - the main character Ransom does believe in Creation, the wonderful expanses of the creation and yes, the heavenly hosts of each planet all bow down to a Most High Oyarsa. So maybe they are throwing the rocks at us. One of the posts said we don't create stuff anymore. Who did? . . . So maybe those on Malacandra (Mars) are tossin' the rocks at our noggins to get us to focus less on the age of the rocks (neat stuff to know) and MORE on the One who created them? (The Object Class of life from which all other class get their attributes!) If you happen to not see things this way, it was your reference to a solid Christian treatise in Science Fantasy that got me going) PS: I do enjoy your subtitles. Usually fun, great play on words, or like this story a good play on ideas by refercne. And keeps out minds going when we con't know what the subtitle refers to.
  • Note:
    Understand the subject before marking a post as off-topic. The by-line references That_Hideous_Strength, by CS Lewis. Mars is Malcandra (sp?). "Pod"..."soreni"...

    **Sigh**

    Ya Know, others besides O'Reilly publish books...
    get one [bn.com].

    Back on topic, myself: I really don't understand how the Martian rocks get to Earth to begin with, but am enjoying watching the theories fly about looking for a place to land. Anyway,<ugh> 'rock on'. </ugh>

    Now hiring experienced client- & server-side developers

  • First this, then the near miss [slashdot.org].

    Let me postulate a theory:

    1. There was life on Mars. One of their largest structures, which only partially survived, was a face.

    2. The Martians thought, "The danger from the sky will never hit us," and 200 million years ago they didn't see it coming.

    3. The impact was so great, they all perished; so great, in fact, that it blew chunks of the planet into Earth's path.

    4. The building blocks of life were contained in ... Nah, that's going too far. ;-)

    Nice conspiracy theory, even without 4. This tells me we need to devote more resources to our "eyes."

    Thing 1

    --

  • This will probably get shot down by a passing astrophysicist, but anyway:

    Could a large meteorite have impacted on Mars circa 200 million years ago and thrown pieces of rock clear of the planet?

    I don't know much about the surface of the red planet, but is there a large enough crater to support this?

    Alternatively, such a large impact could have made a serious hole in the crust, creating a large volcano. This could have been the origin of Olympus Mons (the monster volcano roughly on Mars' equator).
  • And if I understand my bio-geek gf, there are several gigantic and suspicious bottlenecks in the evolutionary tree that could suggest more than one cataclysm in the earth's history.
  • Excuse me, but do you think that if there were astronauts on the Polar Lander, the landing engine couldn't possibly fail as it did for the unmanned vehicle?

    And the usual argument "if there were men on board they would work more toward security" doesn't work, unless you're willing to say NASA likes throwing away huge amount of money and lose its face only because "it's an unmanned probe, who cares?"

    If you can send men securely, you can send a probe as securely, spending a lot less.

    Let's save that money for when we'll really NEED men (and women) on Mars, that is when and if we know for sure there is something that deserves the creative mind and freedom of action a probe will never have.

    Ciao,
    Rob!

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