[meteorite-list] Carancas in the news

[Michael Murray]

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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