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Popular site sheds light on meteorites
Do two meteorwrongs make one meteorite?
By Tony Fitzpatrick
2006 — The mysterious orb you find in your backyard that wasn't there just the day before has to be a meteorite, right?
Wrong. Overwhelmingly the chances are it's a meteorwrong, says Randy
Korotev, Ph.D., research associate professor of earth and planetary
sciences in Arts & Sciences at Washington University in St. Louis.
He says that 998 out of 1,000 meteorites are from asteroids, one out of
1,000 is from the Moon, and one out of 1,000 is from Mars. Of the
hundreds of meteorites that have been found in the United States, none
has been a lunar meteorite, and only one has been a Mars meteorite.
research associate professor of earth and planetary science, examines
fragments of the Sikhote-Alin iron meteorite that fell in Siberia in
1947. The sample is the real McCoy, but Korotev regularly receives
samples from meteorite enthusiasts that are wrong McKongs. Mistakenly
identifed meteorites have the quaint moniker of meteorwrongs.
Korotev is a geochemist whose specialty is analyzing the chemistry
of Moon rocks, whether they have been gathered from the Apollo missions
or collected as meteorites from Antarctica or north Africa or other
areas of the world. In recent years, he's become the go-to guy for
anybody — researcher, amateur or professional meteorite collector — who
thinks he might have discovered a lunar meteorite because of a Web site
he started about 10 years ago that deals in great detail with lunar
Korotev intended for the site to serve his colleagues and the
interested public, and it is as good an educational site on the topic
to be found anywhere. With the advent of very intelligent search
engines, an aggressive, though little known profession of meteorite
dealers — a lunar meteorite retails from $1,000 a gram to $40,000 a
gram — and hobbyists, Korotev's site began drawing questions from the
public about the veracity of their findings. Some people make
appointments to see him and other Washington University geologist
colleagues, but the vast majority e-mail pictures of their findings to
get their answers. While he didn't keep count of all the contacts he
received in the early years, last year alone he received 900 meteorite
"I felt obliged to answer people's questions and in the process of
doing so, found that I was saying the same thing over and over again,"
Korotev explained. "Now, I like to build Web sites and I like
photography, so I came up with the idea of a Web site that could
explain both verbally and visually that your sample is not a meteorite
because. . . There are scores of reasons."
More lucrative than baseball card collecting
"A Photo Gallery of Meteorwrongs" (http://epsc.wustl.edu/admin/resources/meteorites/meteorwrongs/meteorwrongs.htm)
showcases more than 100 objects misidentified as meteorites. Click on
the photo and a caption comes up alongside the object explaining why
the rocks probably are not meteorites and suggesting what it most
likely is and why. The site provides criteria for recognizing space
objects. For instance, freshly fallen meteorites will have a fusion
crust, a glassy coating that forms on the object during descent.
Meteorites also usually are not angular because during their descent
protuberances tend to be ablated away coming through the atmosphere.
Korotev said there is a growing body of meteorite collectors who,
like stamp or baseball card collectors, are seeking samples of every
known lunar or Martian meteorite documented — that's only between 35
and 40 lunar meteorites. Also, people seek meteorite samples for
"I've had two young men tell me they want some grams of a lunar
meteorite for their fiancé's engagement ring," he said. "My reaction
is: Lunar meteorites are not that attractive, get her a diamond.
Besides they were formed on a planet that doesn't have water, which
means that they're unstable in water, and that's not the sort of thing
you want to put in a ring if your fiancé ever wants to wash her hands."
Korotev said that lunar rocks are depleted in volatile elements and
compared to Earth rocks they are low in sodium, potassium, and
rubidium, though high in chromium. There are about 12 different
chemical signatures that indicate a lunar source. Martian meteorites
share some of the same features as lunar ones, except that Martian
meteorites are never rich in feldspar, like most lunar meteorites.
Often, Korotev and his colleagues can do simple, quick tests to
determine if a rock has meteorite potential. If a rock has layers,
strike it — to have layers, gravity is needed. If the rock has low
density, it can't be a meteorite, and he can determine this with a
quick lab test.
Still, people want him to confirm that what they have is a meteorite.
"I've heard this over and over again," Korotev said. "'I heard a
thump and went outside and found this rock that wasn't here yesterday.'
I can't help noticing that every single rock that people show me or
send me a picture of that 'wasn't here yesterday' is just about the
size of a hardball. More than likely, it was chucked into the yard by
some mischief maker."
Korotev said the public can purchase very small samples of
legitimate lunar or Martian meteorites on E-Bay. Big samples of
"regular" — asteroidal — meteorites also can be purchased, and there
are museums, and dealers who can confirm or deny meteorite designation,
and a laboratory in northern Arizona that, for a fee, will do a
complete petrographic — analysis of thin sections of the sample under a
microscope — analysis of rock samples to determine if they are
meteorites. He has the site up to help people and to engage them in
science, and he gets a wide range of responses.
"I had a fellow ask: Do two meteorwrongs make a meteorite?" he said.
"I've had wonderful conversations with schoolchildren in the
Phillipines and housewives in Scotland, but there are some people who
are so convinced that they have a meteorite that they end up not liking
me. I have a place on the site that suggests that before sending to me,
read some of the responses I've gotten from people who don't accept our
conclusions. There are some pretty outspoken people who think that I'm
an idiot. The truth is, it appears human nature just doesn't like to
accept the easy explanation."
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