Meteorite Mayhem III: solved?

By Phil Plait | September 24, 2007 9:13 am

According to a National Geographic news article, the meteorite that struck Peru recently (see here and here) really was a meteorite (and not a missile or anything else), and the reason people got sick in nearby villages is that it struck a location that had arsenic in the groundwater.

Yikes.

The impact site in Peru, filled with arsenic tainted water. Miguel Carrasco/La Razon/Reuters

We may finally have a story that makes sense. Samples of debris indicated it was extraterrestrial, but I wasn’t sure how much weight to give that. The crater looks odd, but it turns out to have hit near Lake Titicaca, and the soil composition and shallow water table may account for the shape. The crater is pretty substantial: note the people on the upper right of the rim in that picture for scale.

The claim now is that the meteoroid was hot when it hit (or the impact itself generated the heat), creating a steam plume tainted with arsenic — everyone who complained of illness has recovered, the report says, by the way. Given that we know it’s a meteorite now, that sounds plausible. Given the size of the crater and the eyewitness accounts, the meteoroid may have been big enough to retain quite a bit of heat when it hit. If it were, say (I am completely guessing here, but with reasonable numbers) a meter or so across and moving at 500 kph, the explosive energy at impact would be the same as 40 pounds of TNT, which actually sounds like it’s in the right ballpark to me. Impact energy is very sensitive to velocity, so if it were moving much faster the yield would be much larger.

Evidently pieces of shrapnel have been found, but I haven’t seen a picture of one! I’d love to; in general such pieces are very interesting and can be lovely.

So I guess it wasn’t a Scud missile, or a downed satellite, or an underground eruption, or or or. What we have here is potentially a lot more exciting. It will also make someone pretty wealthy, I imagine: meteorites are expensive, and ones with known falls and, better, an exciting story behind them, can fetch top dollar.

Tip o’ the Whipple Shield to Slashdot.

CATEGORIZED UNDER: Astronomy, Cool stuff, Science

Comments (57)

  1. Dave Hall

    Now its all making sense. Talk about an unfortunate target. Arsenic in the ground, tossed up by the meteorite.
    Its a better explanation than some sort of Andromeda Strain event. But we all know we won’t hear it from Art Bell unless the arsenic came from space or it was previously deposited by chem-trails.

  2. Mus

    Anyone want to bet how many of those people will stop poisoning the water with arsenic (I presume that’s how it got there)?

    I’m betting 0.

  3. BradC

    Yeah, except they are *naturally occuring* arsenic deposits:

    “Numerous arsenic deposits have been found in the subsoils of southern Peru, explained Modesto Montoya, a nuclear physicist who collaborated with the team. The naturally formed deposits contaminate local drinking water.”

    No poluting industry to blame here.

  4. TheBlackCat

    Now, now, Brad, we all know that is just what “they” want you to think.

  5. My recollection is that typical relative velocities in the inner solar system are tens of km/sec, so 500 kph is on the low side. The earth goes at two pi AU per annum, ie about a billion km in 30 million seconds, or about 30 kps, so that stacks up, more or less.

    I hope the gold rush doesn’t get in the way of analysing what’s in the thing. If it wasn’t for meteorites, we wouldn’t know how old the solar system is, or that it formed near a supernova, or how Vesta formed, and a whole lot else.

  6. Wow, that hole is as big as my entire yard!

  7. But the real question on people’s minds is…

    … can you stand a meteorite on its end on the equinox?

  8. Chris

    I don’t think the crater is that big – it seems the picture was taken very near to the crater, while the barrier has some distance to the actual impact zone.

  9. andy

    The Chicxulub impact (end Cretaceous) was on gypsum-rich rocks, which is predicted to have caused sulfur dioxide aerosol, which would make the ensuing effects on the atmosphere worse, further stressing the biosphere of the time. (I’m not going to go into whether the impact was the sole cause of the K/T extinction)

    So target rock type is significant in assessing impact effects.

  10. “Look at the evidence: the crater doesn’t look like a hypersonic impact crater. The shape is wrong, the size is wrong. There has never, not once, in the history of mankind been a meteorite impact that caused people to become ill.”

    Is the shape and size still wrong?

  11. Bill Bones

    Chris, you noticed the people standing on the opposite rim of the crater? Compared to their height (specially the lone dude to the left), the distance between the water and the rim is about 5 meters… it’s a pretty big crater, and prolly the original report claiming it was 30 meters in diameter got the size right.

  12. Quiet_Desperation

    I *totally* called it first.

    >>> I don’t think the crater is that big

    Really?! You got a bigger recent crater or are you just happy to see me?

    Man, that made *no* sense.

    Still, it IS a crater. How often do we get that? In modern times, that is.

    >>> arsenic in the groundwater.

    And people in the US panic when there’s one part per billion of something left after water treatments, or they learn the sad truth that you can *never* filter out all the particles of rat feces from packaged foods.

  13. RAF

    The picture in this article…

    http://forgetomori.com/2007/science/meteorite-makes-30-meter-crater-in-peru/

    …certainly makes the “crater” look smaller.

    In other words, the picture Phil posted does NOT show people standing “at” the rim.

    Prespective, people…perspective…

  14. RAF

    My error…it is the National Geographic news service that is posting that picture…so it’s not Phil’s “fault” for believing them…if I hadn’t seen the other picture, I would have too. :)

    Surprising though that the National Geographic would lend it’s “name” to a picture obviously meant to deceive.

  15. Chris R.

    Ha ha, Phil said “Titicaca”!

    That is all.

  16. Dan

    And I was so looking forward to kicking some serious Peruvian face-eating space-zombie butt.

    So, how sure are you? I mean, is there some wiggle room in your math that might accommodate some level of zombification?

  17. Grizzly

    Not metallic, but magnetic? Huh?

  18. blf

    The National Geographic story says (on page 2) “The resulting crater resembles a muddy pond measuring 42 feet (13 meters) wide and 10 feet (3 meters) deep.”

    It also says “Preliminary analysis by Macedo’s institute revealed no metal fragments, indicating a rare rock meteorite. Metal stands up better to the heat created as objects enter Earth’s atmosphere, which is why most meteorites are metallic.”

    Ms Macedo is “Luisa Macedo, a researcher for Peru’s Mining, Metallurgy, and Geology Institute (INGEMMET), who visited the crash site”, according to the article.

  19. Bob H

    Wow, my guess in part II was correct. The object hit something that was the cause of the problem. However, if there was arsenic in the groundwater, wouldn’t people have been getting sick from it for awhile now?

  20. Kullat Nunu

    Curious.

    Peru is one of those places where various claims of meteors have been in the news once in a while recently.

    If this is a real one, well, that would be ironic.

  21. David, the atmosphere slows it considerably.

  22. Irishman

    Bob H, they probably would get sick from it, if they drunk it unfiltered. But regular water is not going to aerosol much arsenic on its own, so people aren’t going to get sick just breathing near a pool of it. However, vaporize a big batch and spread it around, and people will get a larger dose.

    Ed Minchau asked:
    >Is the shape and size still wrong?

    The Bad Astronomer posted in the column:

    The crater looks odd, but it turns out to have hit near Lake Titicaca, and the soil composition and shallow water table may account for the shape.

  23. Gary Ansorge

    Hmmm, big hole. Wonder what analyses of fragments will show?

    Gary 7

  24. Why haven’t we seen any aerial photos of the impact crater yet??

  25. Good point. And in a way that depends on size so it’s hard to work out.

  26. It’s interesting because the crater looks like just a big hole without any extraterrestrial involvement. I wonder if there are any other craters like this on the Earth from the last 10,000 years we’ve entirely passed over?

  27. Lurchgs

    That *is* one *SERIOUSLY* deceptive photo.. wide angle, up close – makes the hole in the dirt look big enough to swallow my house instead of just my dog (yes, he’s large – none of those walking footballs for ME)

    still.. isn’t 500k/h a little low? at a meter across, the meteor would mass about 2 tons (give or take, based on earth rock densities).

    Looking at that crater (with a less deceptive shot, provided by RAF), I’d guess it would take more than 40 pounds of TNT – a lot more – to make something similar. A 500 pound bomb makes a hole 3 meters deep – and this crater is 3 meters to the *waterline*. (though.. a 500 pound bomb generally contains a bit less than half its weight in explosive – still, call it 200 pounds of military grade explosive)

    did a decimal point get shifted over one place to far?

  28. Lurchgs, I was just taking a wild stab. I could be pretty far off, but I think it’s order-of-magnitude or so.

  29. Edward Cohen

    Sounds like a lot of people do not want to believe
    that it may be true. Don’t ask me, I am not a
    scientist. But it could possibly have been a meteor
    as well as not.

  30. Helioprogenus

    Now I hate to say I told you, but that scud theory was based on news that was unsubstantiated, and as skeptics, we should be more discerning. I realize that at first, the information did not add up to a meteor, but jumping at possible conclusions before more facts are known can lead to all sorts of false assumptions. When I first heard about the scud theory, I honestly thought it was a joke, and BA was being sarcastic.

    Still, regardless of initial assumptions, now that we’re pretty sure it was a meteor causing the crater, it’s an amazing event in itself, and shows that meteors don’t always behave as expected. It goes to show that perhaps our own ideas of the impact that meteors cause or the impressions that they leave behind may need much revising.

  31. Greg Granville

    Need to get some real experts on this… not some local meteor impact scientist “wannabes”.
    Iron meteorites almost always impact at extremely high hyper-sonic velocities. In which case, the impact crater should look quite different than this. Lower density objects that could decelerate to a speed which would be consistent with the appearance of this crater, would, instead almost always break-apart and burn up high in the atmosphere.
    IF, this really is an impact crater, it’s a highly unusual one, and it deserves study and analysis by a true expert in the field (and, there are only a small handful around the world who qualify)
    Until someone like that examines the site, I think it far more likely to conclude this is a localized geological phenomena, or that it was created by some other “terrestrial” force.
    As far as the arsenic in the water idea is concerned, that all sounds very plausible. Regarding the seismological data, I think it might be a good idea to look at that more closely as well. In particular, how closely correlated is it with the sighting of the fireball.

  32. Quiet Desperation

    >>> nd as skeptics, we should be more discerning.

    *shrug* One day one I said “Meteor. Contamination already in soil.” :)

  33. Keith Harwood

    Pity. I was rather hoping that after the smoke stopped coming out of the crater a tripod walking machine with ray guns would come forth.

  34. RAF

    Call me “overly” skeptical, but I’m not “sure” at all.

    Why is it so hard to get a picture of this “crater” with people standing at the “rim”? Why the “obvious” photographic deception???

  35. RAF

    …and I meant to add…

    There is no way to discern (from looking at the different photographs) just how “big” this “crater” actually is. Doesn’t it bother anyone that there have been no pictures taken of people standing at the rim to give us some sense of scale? Personally, I wouldn’t be surprised if it turns out that this “crater” is 3 meters rather than 30 meters across.

  36. Lurchgs

    BA –

    Wasn’t meaning to try to pin you down that badly – you did state quite clearly it was a WAG. I was just struck by the similarity between this crater and those left by any number of bombs in the past 75 years. So, I thought maybe a decimal point got moved over one column… which makes sense to me, given the number of times I make that mistake in any given day.

    Then there was the May 2 2006 video of the creation of a new crater on the moon – a crater some 14 meters wide and 3 meters deep. According to the story here [http://science.nasa.gov/headlines/y2006/13jun_lunarsporadic.htm], the meteoroid was probably some 25 centimeters across and moving *really* fast.

    So,yeah – without more evidence than flakey pictures, anybody is likely to be operating on large quantities of guesswork.

    As for me, I doubt all the explanations so far. I think it was a giant pre-historic gopher. The noise (and the cause of the local’s illness) was said gopher breaking wind.

  37. Hank Roberts

    There aren’t a whole lot of historical examples of meteorite craters in soft soil with a high water table. Next rainy season it’ll be a puddle after the edges slump back tothe angle of repose, then gone.

  38. Ethyl

    “The object hit something that was the cause of the problem. However, if there was arsenic in the groundwater, wouldn’t people have been getting sick from it for awhile now?”

    As someone mentioned previously, if they were drinking unfiltered water, then yes, but it may also be that vaporized, inhaled arsenic might be more harmful than if you swallow it. IANAD, though, but it just seems likely that you might get sicker faster inhaling this stuf — think about eating a pot brownie versus smoking a big ol’ bong hit :D

  39. Calli Arcale

    RAF sez:
    “There is no way to discern (from looking at the different photographs) just how “big” this “crater” actually is. Doesn’t it bother anyone that there have been no pictures taken of people standing at the rim to give us some sense of scale? Personally, I wouldn’t be surprised if it turns out that this “crater” is 3 meters rather than 30 meters across.”

    It doesn’t bother me, because it seems to me that there hasn’t been a major effort to satisfy the general public’s desire to play armchair geologist. The pictures have been the kind that look good in print media. People made the same sort of complaints about the Hogzilla pics, and that turned out to not really be a hoax. (Yeah, the original pics do inadvertently cause some forced perspective effects, but it’s not a deliberate deception.)

    And it’s worth mentioning that some folks level the same sort of criticisms at the Apollo photographs. Lack of an adequately perfect photo doesn’t meant it’s a hoax.

  40. Zombie492

    just because there was Arsenic does not mean that there isn’t also a Zombifing agent involved. Be ready, in a few months, we are up to our eye-balls in zombies!

  41. RAF

    You think that positioning the boy in such a way as to make the “hogzilla” look bigger was NOT deliberate? It was most certainly a hoax.

    …and this has absolutely nothing to do with the Apollo photographs. This is NOT the same sort of criticism at all.

    But it is the same as the “hogzilla” hoax…proper photographs showing how big the thing is have not been taken as of yet.

  42. skeptigirl

    A simple blood test in the affected people could confirm the complaints were due to arsenic. Until then, I don’t buy it just because it is more plausible than radiation. Mass hysteria is a well documented phenomena just as much as arsenic poisoning is.

  43. Geez, Irishman, I hope you didn’t get windburn, what with the point sailing by so quickly over your head.

  44. Lurchgs

    Raf –

    ok, I really AM picking at nits here… we don’t KNOW that no suitable photographs haven’t been taken. All we really know is that there are none readily available to the general public (i.e. us)

    :)

    not that I doubt your statement either, but as somebody famous once said ” Absence of evidence is not evidence of absence”

    I’m done tweaking you now.

  45. RAF

    Isn’t that a double negative? :)

    But yes, I do see your point.

    Actually all I’m looking for is evidence that I am wrong…until I see that evidence, I’m going to be skeptical.

    That’s all…

  46. RAF

    …we don’t KNOW that no suitable photographs haven’t been taken…

    Isn’t that a double negative? :)

    But yes, I do see your point.

    Actually all I’m looking for is evidence that I am wrong…until I see that evidence, I’m going to be skeptical.

    That’s all…

  47. Irishman

    Ed Minchau, I guess I missed your point. Spell it out in English, as I don’t speak “hint”. My friends can attest to that.

    To me, Phil clarified the evidence it was a meteorite hit, and you then asked if the hole shape and size were still wrong. Well, he already said they seemed wrong but the topography of the ground could be a factor contributing to that appearance. So question already answered. Your point was?

    RAF said:
    > You think that positioning the boy in such a way as to make the “hogzilla” look bigger was NOT deliberate? It was most certainly a hoax.

    A couple of points. First, “Hogzilla” was shot by an adult. There was a second huge hog shot by an 11 year old boy, but that was not “Hogzilla”.

    Second, hoax is a loaded word that is not strictly appropriate. A “hoax” is an intentional fabrication or distortion. Facts for Hogzilla.

    1. There was a real hog. It was very large. (Size clarified later.)

    2. The photos shown are real photos, not photoshopped.

    3. Hogzilla was buried after the photo was taken.

    4. Emails circulated, some of which characterized Hogzilla as being 12 ft long and weighing 1000 lbs. It is unclear where these specific claims came from – the person who shot the hog, or people passing the story along.

    5. National Geographic (“Is It Real?”) contacted the parties and they went and dug up the Hogzilla carcass. They confirmed that it was large, but that it was about 7 1/2 feet long and estimated about 800 lbs, not 12 ft and 1000 lbs. (Estimated because the head was already removed and the carcass had been in the ground for almost a year.)

    6. The guy who shot it and the property owner estimated the weight in the field on their own. 1000 lbs seemed reasonable to them, was probably high, but 800lbs is a good chunk of 1000, and depends on how fine-grained your estimate is. For eyeballing in the field by untrained estimators, is it in the ballpark? YMMV.

    7. The email describing Hogzilla as 12 ft long is clearly a third party describing the picture, not the first-hand account of the shooter. The estimate of length is poorly done and downright wrong. It is possible the person was intentionlly playing up the length, but that does not show connection back to the original shooter.

    So describing Hogzilla as a “hoax” is suggesting that the shooter, the one claiming to have killed the beast, was intentionally misrepresenting the size. There is not enough evidence to show that. Although it is possible (even probable) there was some “fish story” involved, there isn’t proof of that. It remains “I killed the biggest wild (feral) hog I’ve ever seen, and here’s a picture.” Other people exaggerating and misrepresenting what is clearly shown in the picture is something else not attributable to the photo owner.

    Regarding the boy who shot the second hog, there was indeed a large hog, it really was 9 ft long and 1000 lbs, as confirmed by the guy who sold it to the hunting preserve owner where the kid shot it. No hoax there, either. What you have is a kid posing behind the huge carcass of his kill, with some slight distortion from perspective. But not much, and not intentional, just what happens when you try to pose with a large item and the best place to stand is behind it.

    http://www.snopes.com/photos/animals/hogzilla.asp

  48. Irishman

    Ed, suddenly it dawns on me you perhaps were referring to the remark about there not being a history of meteorites causing illness. Guess I did miss that. ;-)

    RAF said:
    > Surprising though that the National Geographic would lend it’s “name” to a picture obviously meant to deceive.

    What is your evidence that picture was intended to deceive, rather than intended to show the shape and texture of the crater? The people in the background could have been incidental to the photographer’s intent. Perhaps the photographer snapped several photos, some of the crater, some to show background, and then the website editor picked one based upon aesthetics, or random coin flip, rather than an attempt to clearly or unclearly depict the size.

    But yeah, that photo is misleading if you are intepreting the people as being on the rim. Perspective is important in interpretation. I, too, would like to see a good size comparison photo.

  49. RAF

    Just to be clear…yes, I am saying that they intentionally misrepresented the size of the thing.

    Please go to the following website…

    http://www.stinkyjournalism.org/newsdetail.php?id=45&keyword=monster%20pig

    …and tell me how it wasn’t intentional. Or perhaps explain why the boy changes size, while the hog remains the same. Which picture accurately represents the size difference between the boy and the hog?

    Back on topic…all I’m saying is that people can be fooled by perspective, and that I would like to see a picture of this crater that removes all doubt as to it’s size.

  50. Buzz Parsec

    Helioprogenus –

    Quit your false accusations. You are totally full of it. No one on this blog *ever* claimed it was a SCUD. The SCUD hypothesis was always just that; a *HYPOTHESIS*. If you don’t know what that means, look it up in a dictionary.

    This is the fallacy of the excluded middle. I (and others) had doubts about the “meteor” explanation. The BA posted about the “SCUD” explanation. That answered some of the questions. (Residual fuel could have explained the illnesses, warhead or unburned fuel (e.g. from an early engine cut-off) could explain the crater.)

    But it certainly wasn’t conclusive. No one ever said “Case closed. It was a SCUD.”

    You seem to think that if someone doesn’t accept that it was a meteor, they must believe it was a SCUD. That’s idiotic. There is such a thing as reserving judgement and awaiting more evidence. That’s what a skeptic does in the face of conflicting or insufficient evidence.

    Making arguments one way or the other is *not* the same thing as coming to a conclusion. It is just a method of examining the evidence and determining what we do and do not know so far.

  51. Irishman

    RAF, thanks for the link. I had not seen that, or looked much at the mosterpig claims. There does appear to be something fishy with the photographs.

  52. Bill clem

    The new Novel MICROBE details a bacteria-carrying meteor that hit Ft. Miles, Delaware in 1947, killing several dozen soldiers. But is this fiction, or did the Army cover it up. Fiction or Narrative non-fiction? You decide.

  53. Mr. Bill

    Wow, I managed to miss this one entirely! Or I am just getting old and forgot it.

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