132 lines
4.5 KiB
Plaintext
132 lines
4.5 KiB
Plaintext
SUBJECT: CLUES TO RED PLANET'S PAST FILE: UFO3345
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======================================================================
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Article 1638 of sci.geo.geology:
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From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
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Newsgroups: sci.space,sci.astro,sci.geo.geology
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Subject: Water from Meteorite Provide Clue to Mars Past
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Keywords: Mars, Viking, Mariner 9
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Message-ID: <1992Mar13.162752.22126@elroy.jpl.nasa.gov>
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Date: 14 Mar 92 00:27:19 GMT
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Sender: news@elroy.jpl.nasa.gov (Usenet)
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Reply-To: baalke@kelvin.jpl.nasa.gov
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Organization: Jet Propulsion Laboratory
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Lines: 82
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News-Software: VAX/VMS VNEWS 1.3-4
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Nntp-Posting-Host: kelvin.jpl.nasa.gov
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Paula Cleggett-Haleim
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Headquarters, Washington, D.C. March 13, 1992
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(Phone: 202/453-1547)
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Kari Fluegel
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Johnson Space Center, Houston
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(Phone: 713/483-5111)
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RELEASE: 92-35
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METEORITES' WATER PROVIDES CLUE TO RED PLANET'S PAST
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A single drop of water rarely causes excitement in the scientific
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community, but a few milligrams of liquid extracted from a meteorite may
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have started to answer one of the great mysteries of planetary science.
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Were the channels seen on the surface of Mars carved by once great
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torrents of rushing water or by some other process?
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Dr. Everett Gibson of NASA's Johnson Space Center (JSC), Houston,
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Planetary Sciences Branch; Dr. Haraldur Karlsson, formerly a National
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Research Council postdoctoral fellow at JSC; and scientists at the University
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of Chicago have analyzed drops of water extracted from several meteorites
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believed to have come from Mars and have concluded that the oxygen
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isotopes in the water were extraterrestrial.
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"It's really a beautiful piece of scientific work to do this
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analysis,"
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Gibson said. "We are extremely pleased with the results of this team
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effort."
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The results of the team's findings are being published in today's issue of
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the
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journal SCIENCE.
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Photographs returned to Earth from the Mariner 9 and Viking
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spacecraft show features that suggest Mars once may have had a water-rich
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atmosphere and flowing water on its surface. Sometime in its history,
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however, most of the water apparently disappeared, leaving only minute
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amounts of vapor in the atmosphere.
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Through the years, several meteorites have been collected on Earth
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that scientists have identified as Martian by comparing them to information
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gleaned by the Viking spacecraft. Six of these meteorites were used in the
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water extraction procedure.
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Gibson said the meteorites were heated in steps in a small vacuum
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system at JSC to extract trace amounts of water. The water samples were
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hand-carried to the University of Chicago for analysis of oxygen isotopes.
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Although the water droplets were less than 1/64ths of an inch in diameter,
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it was enough to do the analysis.
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The analysis determined that the oxygen isotopes in the water were
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different from the oxygen isotopes in the silicate portion of the meteorites.
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In other words, the water had a different parent source than the oxygen in
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the silicate minerals in the meteorites. That parent source could have been
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the Martian atmosphere, an ancient Martian ocean or even a comet that
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impacted the planet, Gibson said.
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The lack of homogeneous oxygen isotopes on Mars supports the theory
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that Mars does not have plate tectonics. If such a process had been active
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on Mars, the oxygen isotopes would have been homogenized as they are on
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Earth.
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Findings from the work completed by the team may answer some
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questions about the processes operating in the solar system, but the findings
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raise other questions -- what happened to the water on Mars and does Earth
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have the same destiny?
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"These are large and difficult questions to comprehend," Gibson said,
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"but perhaps if we can trace the origins and alterations of planetary
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atmospheres and oceans, the evolution of our solar system may be better
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understood."
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Besides Gibson and Karlsson, who is now in the Department of
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Geosciences at Texas Tech University, Lubock, team members included
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Robert N. Clayton and Toshiko K. Mayeda of the Department of Geophysical
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Sciences and the Enrico Fermi Institute at the University of Chicago.
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- end -
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** End of Article **
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Don
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*********************************************************************
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* -------->>> THE U.F.O. BBS - http://www.ufobbs.com/ufo <<<------- *
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********************************************************************* |