[meteorite-list] Mars Rover Discovers A Potential Meteorite

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Sat Jan 15 01:24:07 2005
Message-ID: <41E8B6DE.691BC832_at_bhil.com>

Hi,

    I have nothing to contribute as to whether the object is or is not a meteorite, but there is one thing
about discovering a meteorite on Mars that disturbs me.
    The performance of the rovers have greatly exceeded their planned lifetime and reach, but even so, the
two them have only covered a few thousands of meters. Assuming that their cameras only scan closely
objects within a few hundred meters of their position as they move along, the total land area scanned in
detail by the rovers can only amount to one square kilometer or maybe two. (Five kilometers of travel
times 200 meters of total sideview equals one square kilometer.)
    What are the odds of finding a good-sized meteorite in ANY 1 or 2 square kilometers? Since we can
assume the choice of Martian location is random, let's re-phrase that to: What are the odds of finding a a
good-sized meteorite in EVERY 1 or 2 square kilometers of Mars?
    Frankly, it would mean that meteorites are incredibly abundant on Mars. It would mean a very high fall
rate. It would mean meteorites survive for a very long time in the Martian environment. But one big
meteorite per square kilometer would mean that Mars has tens of millions of big meteorites on its surface.

    And by the normal power law distribution, there should be hundreds of millions of meteorites 1/3 this
size and billions 1/10th this size and a million meteorites three times this size, and so on. That's a
helluva lot of meteorites! (And you thought NWA's would flood the market...)
    Or maybe the rovers are just incredibly lucky meteorite hunters? (Can I rent one?)
    Yes, it could just be a fluke, wild luck, like winning the lottery, but the entire mission (despite
being targeted at potential formerly wet sites), like all missions, is based on the principle that a
random sample is in the long run a representative sample.
    So, it sits there on its sand dune. If that sand dune were one square kilometer of North West Africa
picked at random, what are the odds there'd be a meteorite sitting on it?
    Is it too good to be true?


Sterling K. Webb
--------------------------------------------------------------
At 04:24 PM 1/14/2005, Ron Baalke wrote:

> >
> >
> > >http://www.newscientist.com/article.ns?id=dn6883
> > >
> > >Mars rover discovers a potential meteorite
> > >Kelly Young
> > >New Scientist
> > >January 14, 2005
> > >
> > >NASA's rover Opportunity has spotted an unusual rock on Mars that may be
> > >a meteorite.
> > >
> > >The rover first glimpsed the rock two weeks ago as it approached the
> > >remains of its heat shield, which plummeted to Mars during the rover's
> > >descent through the atmosphere in January 2004.
> > >
> > >The object, about the size of a potato, caught the eyes of ground
> > >controllers because of its unusual pitted surface. "We've been seeing
> > >little rocks on the plain since the start of the mission," says Steven
> > >Squyres at Cornell University, the Mars rovers' chief scientist. "We all
> > >just kind of assumed they're little pieces of Martian basalt."
> > >
> > >But Opportunity's infrared spectrometer, called Mini-TES, saw that this
> > >object did not radiate thermal energy at the frequencies expected of
> > >"typical" Martian rocks, leading scientists to hypothesise that the
> > >object might in fact be a meteorite rich in metal.
> > >
> > >Opportunity has stayed next to the object and will continue making
> > >measurements over the weekend to confirm whether this is indeed a
> > >meteorite. Squyres says they should have the results by Monday or
> > >Tuesday. "It could be any number of things if somehow we got faked out
> > >by the Mini-TES data," Squyres cautions.
> > >
> > >Unexpected circumstances
> > >
> > >Meteorites are objects that survive the - sometimes fiery - fall to a
> > >planet's surface from space. Only about 2% of the meteorites that land
> > >on Earth are made of nickel and iron. The rest are made of rock.
> > >
> > >Squyres says that the rover's rock abrasion tool, which is used to grind
> > >away the surface of rocks, had never been tested against a metal like
> > >nickel. "I didn't see this coming," he told New Scientist.
> > >
> > >Opportunity will celebrate its first birthday on the Martian surface on
> > >25 January. So far, it has trekked over 2000 metres around Meridiani
> > >Planum and recently weathered its first dust storm.
> > >
> > >Opportunity's twin rover, Spirit, has been roaming around the other side
> > >of the planet on an area called Husband Hill, but it has had trouble
> > >getting around because its wheels have been slipping on the sandy,
> > >sloped surface. Ground controllers have also been monitoring a
> > >fist-sized rock which has become stuck in the wall of Spirit's wheel.
> > >
> > >
Received on Sat 15 Jan 2005 01:23:27 AM PST