[meteorite-list] Dust In 'Earth's Attic' Could Hold Evidence Of Planet's Earliest Life

From: Michael L Blood <mlblood_at_meteoritecentral.com>
Date: Thu Apr 22 10:00:09 2004
Message-ID: <B961F394.10F8%mlblood_at_cox.net>

Hi Ron,
    Thanks for the post...
    Very interesting article - it has always been my contention that we will
one day have an "Earth Meteorite" fall or find. Bob Haag's "holy grail" has
always been a meteorite with fossil evidence of life (ALH84001?) but mine
has always been a meteorite that consisted of material knocked off the
earth, then returned via a fall.
    I'm waiting.........
    Best wishes, Michael



on 7/22/02 2:29 PM, Ron Baalke at baalke_at_zagami.jpl.nasa.gov wrote:

>
> http://www.washington.edu/newsroom/news/2002archive/07-02archive/k072202.html
>
> Office of News and Information
> University of Washington
> Seattle, Washington
>
> FROM: Vince Stricherz, 206-543-2580, vinces_at_u.washington.edu
>
> FOR IMMEDIATE RELEASE: July 22, 2002
>
> Dust in 'Earth's attic' could hold evidence of planet's earliest
> life
>
> The dust has been piling up in Earth's attic for billions of
> years, and now some scientists want to sift through the
> accumulation to see if they can find evidence of the planet's
> earliest life.
>
> "It is up there. I don't know how common it is, but somewhere up
> there is at least one fist-sized chunk of rock with Earth's name
> on it," said John Armstrong, a University of Washington doctoral
> student in astronomy and astrobiology. "It would probably take
> hundreds of years of human habitation to find it and recognize
> it, but it's there."
>
> "Up there" is the moon, what Armstrong and his colleagues refer
> to as Earth's attic. And while he doesn't expect to actually find
> a large chunk of Earth rock, he believes there is likely a wealth
> of planetary debris in the form of fine particles on the moon's
> surface.
>
> In an upcoming edition of Icarus, an international journal of
> solar system science, Armstrong and colleagues Llyd Wells, a UW
> graduate student in oceanography, and Guillermo Gonzalez, an
> assistant physics and astronomy professor at Iowa State
> University, argue that humans should seriously consider returning
> to lunar exploration. Any mission, they say, should include a
> search for fossils of some of Earth's earliest microbial life.
>
> In its very early history, 3.8 billion to 3.9 billion years ago,
> comets and asteroids constantly bombarded the Earth. Some of
> those bodies hit with such force that chunks of the planet's
> surface were ejected beyond the pull of its gravity. The three
> astrobiologists believe some of that ejected material went
> directly to the lunar surface, while other material went into
> orbit and some gradually fell to the moon.
>
> Finding rocks, or even particles, from that period could be
> invaluable in understanding how life on Earth came to be as it
> is today, since any fossils found likely would be from a time
> long before life on Earth developed great complexity and
> diversity.
>
> Because of the moon's position in the inner solar system, in
> theory it has collected material from all the planets. Earth
> matter probably is most abundant, since it is closest to the
> moon, but Armstrong, Wells and Gonzalez expect that fallout
> from Mars and Venus also is abundant enough that it could be
> recovered. They have calculated that, on average, perhaps 22
> tons of Earth material is spread over every 38 square miles
> of the moon.
>
> If they are right, Armstrong said, that means about 10 parts
> per million of lunar material originated on Earth. However, it
> would not necessarily be identifiable as Earth material. And
> while material blasted directly to the moon probably came down
> on the side facing Earth, any material that ended up in orbit
> could have been deposited anywhere on the lunar surface.
>
> "One thing we're still debating is where would be the best place
> to look," Armstrong said.
>
> The scientists believe Earth material from that long ago
> probably became buried over time, so one strategy they have
> devised is to look for recent craters in which old rocks have
> been excavated. They also are searching through lunar samples
> already returned to Earth, on the off chance those samples might
> contain rocks that originated on the planet. They would be able
> to tell by isotope ratios or by determining whether materials
> in the rocks were formed in water -- something that cannot occur
> on the moon.
>
> At the very least, Armstrong hopes to find dust from pulverized
> Earth rocks, material that can be dated and can give clues about
> the history of bombardment by asteroids and meteors and how that
> affected evolution. If materials are more intact, they might
> contain interesting elements that would shed light on the early
> Earth's environment and how life existed at that time. Less
> likely, he said, would be the discovery of rare, volatile
> elements that would tell about the early atmosphere. The
> least likely find -- and the one most prized -- would be
> microbiological fossils from 3.9 billion years ago.
>
> "The part I like about this is that it makes the moon a window
> on the early Earth," Armstrong said. "It also would give us
> access to samples you can't get anywhere else at the moment."
>
> Currently there are no plans for a U.S. mission to the moon,
> though other nations are considering the possibility. It has
> been 30 years since the National Aeronautics and Space
> Administration's last manned mission, and three years since
> the controlled crash of the robotic Lunar Prospector spacecraft
> in a search for water on the moon.
>
> Armstrong believes a new lunar mission would benefit science
> on several levels and could help prepare and test systems for
> eventual Martian exploration. To search for material of Earth
> origin, he suggests the inclusion of a rover that could
> systematically pass over a specific area, conduct tests and
> prepare samples to be launched back to Earth. The only way
> to find the Earth rocks, he said, is to find a way to look
> specifically for them.
>
> "If you find one of these things, it's going to be hard to
> convince someone that it's of Earth origin," he said. "But if
> you find more than one, then you can begin to classify them as
> a group of materials and begin to make a more convincing case."
>
> ###
>
> For more information, contact Armstrong at (206) 543-9039 or
> jca_at_astro.washington.edu; Wells at (206) 543-0147 or
> chimera1_at_ocean.washington.edu; or Gonzalez at (515) 294-5630
> or gonzog_at_iastate.edu
>
> IMAGE CAPTION:
> [http://www.washington.edu/newsroom/news/images/lunar.jpg]
> The moon as seen from the Stardust spacecraft during a flyby of
> Earth in 2001. (Jet Propulsion Laboratory)
>
>
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Received on Mon 22 Jul 2002 08:38:28 PM PDT