[meteorite-list] Carancas in the news

From: Michael Murray <mmurray_at_meteoritecentral.com>
Date: Tue, 26 Feb 2008 17:22:49 -0700
Message-ID: <7266A0AA-DF98-44BD-8F4A-1C978569B900_at_montrose.net>

I certainly agree with you Mr Webb. That willingness to share by
people in the know such as yourself, and Mr. Matson, and Mr.
Lebofsky, and quite a few others with the wealth of knowledge,
training and expertise on meteor/meteorite and so many other related
sciences, is definitely a big plus for the Met-List. My hat is off
to all of you. And thank you.
Mike in CO

On Feb 26, 2008, at 3:47 PM, Sterling K. Webb wrote:

> Hi, All,
>
> The papers on Carancas referred to are this one...
> http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1216.pdf
>
> ...and this one:
> http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2446.pdf
>
> The first paper suggests, by an analysis of witness reports
> from the surrounding area, an azimuth of 82? and an altitude
> of 63? for the incoming trajectory, with an impact velocity of
> 3000 m/sec. Orbital calculations based on this track suggest
> a body of low inclination (<5? ) but in an orbit very different
> from known near-Earth asteroids.
>
> An unique, or at least odd, object, with an unique, or at least
> odd, orbit. It came from somewhere else, folks... Its strange
> appearance and texture show a very heavily shocked history.
>
> The second paper, which studies the impact effects on the
> materials of the locality, suggests that many of the shock features
> mean a greater impact velocity, perhaps 4000 m/sec or more.
>
> Their analysis of the stratigraphy of the crater suggests that
> the "bolide" reached the ground in one piece and penetrated
> intact to the depth of about 1/3rd of a meter before "exploding."
> Large overturned blocks of ejecta are "riddled" (their word)
> with meteoritic fragments ON THE UNDERSIDE.
>
> Both papers are short and sweet (2 pages) and they are worth
> the read.
>
> We've been having this discussion on the List about the
> List, and the Carancas story is a perfect example of the virtues
> of the List and what it can do in its informal way. The suggestion
> that the "boiling" and odors of the crater were due the thermal
> dissociation of troilite (which is abundant in the meteorite) was
> first made here on the List (and first made anywhere) by member
> Piper R. W. Hollier.
>
> From that, others were able to calculate that the impact
> velocity had to be in excess of 1611 m/sec, probably at least
> twice that, to vaporize the troilite -- a figure that matches that
> calculated in the first paper cited above.
>
> There were arguments presented for a high altitude angle
> for the impact (later determined to be 63?) and for an orbit like
> that suggested in that first paper. In fact, a good deal of this
> information about Carancas presented in these papers could
> be found, in somewhat more speculative form, on the lengthy
> and voluminous List discussion of Carancas in the first weeks
> after the event.
>
> There was nothing else like this List discussion of Carancas
> going on anywhere else and no other place where information
> could be found, sifted, and analyzed, or witness reports could
> be found. There was even a good explanation of how the
> "bolide" managed to get to the ground in defiance of "the
> models" which all say, no way.
>
> All I'm saying here is: "Hooray for the List." There's
> nothing else like it.
>
>
> Sterling K. Webb
> ----------------------------------------------------------------------
> ----------
> ----- Original Message -----
> From: "Darren Garrison" <cynapse at charter.net>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Tuesday, February 26, 2008 10:24 AM
> Subject: [meteorite-list] Carancas in the news
>
> http://cosmiclog.msnbc.msn.com/archive/2008/02/25/701427.aspx
>
> Meteorites spark mysteries Posted: Monday, February 25, 2008 8:20
> PM by Alan
> Boyle
>
> Five months after a meteorite made an international splash in Peru,
> experts
> are
> suggesting explanations for some of the space rock's effects - for
> example,
> the
> sickening odor villagers smelled at the crash site, and the bubbles
> that
> were
> seen emanating from the water-filled crater left behind. But a
> study due to
> be
> presented next month also raises fundamental questions about the
> event. In
> fact,
> an international research team declares that the impact "should not
> have
> happened" at all.
>
> Yet another study sets forth a mystery surrounding two other
> meteorites
> found in
> Antarctica a couple of years ago. The rocks don't match any other
> class of
> meteorite - so where did they come from?
>
> The two studies are among hundreds submitted for the annual Lunar and
> Planetary
> Science Conference, scheduled March 10-14 in League City, Texas. The
> conference
> offers the cream of the crop in planetary science - focusing on topics
> ranging
> from the solar wind, to Mercury and Mars, to the icy dwarfs on the
> solar
> system's edge.
>
> The Peruvian meteorite impact comes in for a fresh round of scientific
> scrutiny
> in a study submitted by researchers from Brown University and
> institutes in
> Peru
> and Uruguay. Just after the impact was reported, some scientists
> doubted
> whether
> a meteorite was actually responsible for the crater - but subsequent
> analysis
> proved that a stony space rock was involved (as opposed to a denser
> iron
> meteorite).
>
> Scientists previously thought that stony meteorites on the scale of
> the one
> that
> hit Peru would break apart into little pieces before they hit the
> ground.
> The
> fact that this one survived to create a 40-foot-wide crater threw the
> researchers what they called a "hypervelocity curveball." They said
> the
> standard
> model used to estimate the effects of stony meteorites will need to be
> revised
> as a result.
>
> The study does propose two possible explanations for the reports of
> "boiling
> water" seen within the crater: The bubbles could have come from the
> compressed
> air that surrounded the meteorite as it blasted into the wet earth
> - or it
> could
> have been caused by clumps of clay that dissolved and frothed as
> they fell
> into
> the crater.
>
> "These two processes may have been responsible for local reports of
> water
> bubbling up from the floor soon after impact," the researchers
> wrote. "While
> there would have been heat generated at impact, it is unlikely that
> this
> could
> have sustained bubbling an hour later."
>
> Meteorite hunter Michael Farmer, who visited the site last year
> soon after
> the
> impact, has said the sickening odor that villagers said emanated
> from the
> crater
> was most likely caused by sulfurous compounds such as triolite
> interacting
> with
> the ground water - and there's nothing in the latest study that
> contradicts
> that
> suggestion.
>
> The Peruvian meteorite may be in for another shot at fame: Just
> last week,
> Living in Peru reported that Japanese investors are interested in
> building a
> space museum near the impact site, and that National Geographic is
> planning
> a
> documentary about the meteorite.
>
> Now to the other space-rock study: Meteorite hunters from the Lunar
> and
> Planetary Institute and NASA's Johnson Space Center reported
> finding a pair
> of
> specimens in 2006 in Antarctica's Graves Nunataks area.
>
> "These meteorites are not obviously like any other meteorites, so
> their
> origin
> is unclear," the Lunar and Planetary Institute said in its media
> advisory.
> "The
> mineralogy and chemical composition of these meteorites are so
> unusual that
> scientists have been struggling to find the right term to describe
> them.
> Numerous parent bodies have been proposed. Could they have come
> from the
> moon?
>> From Venus? Scientists are currently debating these issues."
>
> The researchers behind the study say they're not finished with their
> analysis of
> the rocks, and more findings may emerge at next month's conference.
> So stay
> tuned as the meteorite tales and other mysteries are fully brought
> to light.
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Received on Tue 26 Feb 2008 07:22:49 PM PST