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Topic: ALH 84001

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In the News (Thu 23 Nov 17)

  PSRD:: Carbonates in ALH 84001: Part of the Story of Water on Mars   (Site not responding. Last check: 2007-07-20)
Therefore, unless ALH 84001 is a particularly rare sample that escaped intense alteration, the hydrosphere of Mars may not have interacted with the rocks as thoroughly as planetary geologists have inferred from the presence of river networks and other features formed by flowing water.
Although most researchers studying ALH 84001 assume that mobilization of feldspathic glass requires high temperatures, experiments have shown that when silica glasses are exposed to high static pressures (more than 10 times the pressure at the surface of the Earth) their viscosity (resistance to flow) can drop many orders of magnitude without significant temperature elevation.
Therefore, unless ALH 84001 is a particularly rare, particularly pristine sample, the hydrosphere of Mars may not have interacted with the rocks as thoroughly as planetary geologists infer for Mars.
www.psrd.hawaii.edu /July04/carbonatesALH84001.html   (4254 words)

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The carbon in ALH 84001 with the least 14C is also the richest in the stable carbon isotope 13C, and its 13C abundance is the same as measured for martian carbonates in ALH 84001 and other martian meteorites.
As ALH 84001 traveled between Mars and the Earth, it was bombarded by cosmic rays, high-energy particles from the Sun and the galaxy.
The PAHs in ALH 84001 are not merely a mixture of PAHs from CM chondrites and from the Allan Hills ice.
www.seds.org /~spider/spider/Mars/mmet_papers.txt   (10032 words)

 What is ALH 84001?
ALH 84001 is a meteorite, a rock that fell to Earth from space.
ALH 84001 formed originally from molten lava, about 4.5 billion years ago, which is called its igneous age, possibly from an ancient martian volcano.
ALH 84001 is also similar to an important group of igneous meteorites (the diogenites), and was classified as one of them until 1994 when its martian origin recognized by Mittlefehldt (1994).
www.lpi.usra.edu /lpi/meteorites/The_Meteorite.html   (832 words)

If ALH 84001 were shielded from cosmic rays inside a larger boulder during part of its journey in space, it could have spent more time there while only accumulating 12-17 million years worth of exposure.
ALH 84001 was discovered in the 1984-1985 Antarctic summer by a member of the ANSMET meteor-collecting program of the U. National Academy of Sciences, NASA and the Smithsonian Institution.
ALH 84001 was re-typed in 1994, still not as an SNC, but as a probable "Martian" meteorite.
exobio.ucsd.edu /Space_Sciences/alh84001.htm   (1534 words)

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ALH 84001 was exposed to cosmic rays for 14.4 ± 0.7 million years, which probably is the time when ALH 84001 was blasted off Mars.
17] Shearer C.K., Layne G.D., Papike J.J., and Spilde M.N. Sulfur isotope systematics in alteration assemblages in martian meteorite ALH 84001.
In particular, ALH 84001 is an igneous rock, while the C1s have been altered at low temperatures to clays, serpentine, and similar water-bearing silicate minerals.
www.lyon.edu /projects/marsbugs/1998/19980401.txt   (15431 words)

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ALH 84001 and the other 'Martian meteorites' are nearly certain to be from Mars, because they contain traces of Mars atmosphere gas.
ALH 84001 is somewhat magnetic—it formed in a moderately strong magnetic field (like the Earth's magnetic field now), and some of that magnetism was trapped in the rock as it formed.
The case for traces of ancient Martian life in ALH 84001 was neither proved nor disproved at the 28th Lunar and Planetary Science Conference.
www.agu.org /sci_soc/eis/9710/eistrem.html   (1636 words)

 SPACE.com -- Controversy Continues: Mars Meteorite Clings to Life - Or Does It?
Others suggest that any "living proof" of biology in ALH 84001 is little more than terrestrial contamination stuff that eked its way into the meteorite after it came to rest on Earth.
But for skeptics, ALH 84001 as a showboat of Mars life is a dead issue.
ALH 84001 is a very complex rock, loaded with multiple sets of data, said Everett Gibson, senior scientist and co-leader of the Mars research team at the NASA Johnson Space Center.
www.space.com /scienceastronomy/solarsystem/mars_meteorite_020320.html   (1129 words)

 PSRD: ALH 84001 magnetite   (Site not responding. Last check: 2007-07-20)
The magnetite grains reside in tiny grains of iron-magnesium-calcium carbonates, which are typically 50-200 micrometers across and are dispersed throughout the ALH 84001 meteorite as disk-shaped or spheroidal grains, or, in the case of carbonates that enclose silicate fragments, as irregularly shaped grains.
Although all workers agree that the magnetites in ALH 84001 were formed on Mars and may contain an important record of an ancient Martian magnetic field, many have argued against a biological origin for the magnetites.
Since we found much evidence for localized shock melting of silicate minerals in ALH 84001, and there is additional evidence that the rock was heated by impact 4 Byr ago, it is probable that the carbonate was decomposed by impact heating, at this time, rather than by deep burial in the planet.
www.psrd.hawaii.edu /May02/ALH84001magnetite.html   (3575 words)

 Life on Mars: Meteorites
ALH 84001 was found in December 1984 in Antarctica by a U.S. meteorite-hunting expedition.
Other rock samples besides ALH 84001 were treated exactly the same as the ALH 84001 samples with the bacteria shapes -the bacteria-shaped features were not seen on the other samples, and were not seen on samples of ALH 84001 without carbonate mineral globules.
ALH 84001 is maddeningly difficult to work with -- it seems to provide few unambiguous clues (or are we blind to them?).
www.resa.net /nasa/mars_life_meteor.htm   (5127 words)

Alh 84001: a message from mars or perhaps some other planet
ALH 84001 is a meteorite picked up in the Allan Hills of Antarctica a decade ago.
Space scientists think ALH 84001 was blasted off the Martian surface by an impacting body 14-18 million years ago, based upon its exposure to cosmic rays while circling the sun, edging ever closer to earth.
www.science-frontiers.com /sf101/sf101a03.htm   (251 words)

 SPACE.com -- 'Mars Meteorite's' Link to Life Questioned
In December 1984, ALH 84001 -- often called the "Mars rock" -- was picked up in Antarctica by a National Science Foundation-sponsored meteorite-hunting expedition.
ALH 84001 has provided a great technical challengeto study a rock at diverse scales, to relate what we see at the centimeter scale to what is going on at the nanometer scale.
ALH and the discovery of extrasolar planets have also stimulated the expanding new field of astrobiology, Scott added.
www.space.com /scienceastronomy/solarsystem/mars_meteor_020514.html   (1101 words)

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Their arguments for high temperature all assumed chemical equilibria among carbonate and silicate minerals in ALH 84001; mineral compositions and chemical theory suggest no chemical equilibria, so the inferences of high temperature are not valid.
Micron-wide veinlets of feldspar-composition glass in pyroxene grains, and veinlets of this glass and carbonate minerals, suggest that all the shock effects in ALH 84001 all came from a single shock event, which must have melted both the feldspar and the carbonate and injected them into the pyroxene.
Sulfur in ALH 84001 pyrite is somewhat heavy, with d34S between +2.0 and +7.3% (as was found by Shearer et al., 1996).
www.lyon.edu /projects/marsbugs/1997/19970507.txt   (5499 words)

 Aliens on Earth
Most planetary scientists believe that ALH 84001 formed originally from molten lava, about 4.5 billion years ago, which is called its igneous age, possibly from an ancient Martian volcano.
According to this theory, long after ALH 84001 crystallized from molten lava and cooled, about 4.0 billion years ago, it was heated again and deformed by a strong shock.
They presented evidence that ALH 84001 is from Mars, that it was infiltrated by liquid water while it was on Mars, and that the water infiltrated very long ago.
www.datasync.com /~wizard/Aliens.html   (3187 words)

 Ages of Unknown Meteorites   (Site not responding. Last check: 2007-07-20)
For ALH 84001, it yields a crystallization age of 4.5 billion years ago (Jagoutz, 1994; Nyquist et al., 1995).
Jagoutz's (1994) data suggest a younger Rb-Sr age for ALH 84001, and Wadhwa and Lugmair (1996) measured a Rb-Sr age of 3.8 billion years ago.
For ALH 84001, isotopes of the elements helium (3He), neon (21Ne), and argon (38Ar) have been used to calculate a cosmic ray exposure age.
set.lanl.gov /programs/mars/Ages.htm   (772 words)

 Meteorite Two   (Site not responding. Last check: 2007-07-20)
One such meteorite named ALH 84001 was used in such a comparison.
The data for ALH 84001 was determined to be 10.4 x 10^3 atoms/cubic centimeter.
The data for ALH 84001 was determined to be 2.3.
set.lanl.gov /programs/mars/Meteor2.html   (465 words)

 Another Martian meteorite hint
But whether these shapes will be as hotly contested in the scientific community as those from ALH 84001 remains to be seen.
"84001 formed about 4.5 billion years ago and its carbonate globules, which contain the supposed fossils in it, formed at about 4 billion years," he explains.
Because they're very different in chemical and mineral composition, Treiman reasons that 84001 and Nakhla must have come from different places on Mars because their ages are so different.
www.exn.ca /html/templates/printstory.cfm?ID=1999030354   (762 words)

 ALH 84001:  Recent Scientific Papers Explained   (Site not responding. Last check: 2007-07-20)
The amino acids in ALH 84001 are almost exactly in the same proportion as in the Antarctic ice -- the proportions of DL-serine to glycine to L-alanine are approximately 3:3:1.
This similarity of terrestrial and ALH 84001 amino acids leaves little doubt that they are primarily terrestrial contamination, derived from amino acids in the ice that was around ALH 84001.
Ar age of ALH 84001 represents an asteroid impact onto Mars (Treiman, 1995), and that impact was approximately at the same time as the large impact basins formed on the Moon.
www.astro.virginia.edu /class/oconnell/astr121/test/marslife-critcomm-398.html   (15174 words)

 ipedia.com: ALH 84001 Article
ALH 84001 is a meteorite found in Antarctica in December 1984 by a team of US meteorite hunters from the ANSMET project.
Like other members of the group of SNCs, ALH 84001 is almost certainly from Mar...
Like other members of the group of SNCs, ALH 84001 is almost certainly from Mars, blasted off of the surface some 3.6 billion years ago in a meteorite impact.
www.ipedia.com /alh_84001.html   (198 words)

 ALH 84001
ALH 84001 and Its Fossils(?) A Gallery of Images
Row 5: Detailed, false color SEM image of ALH 84001 carbonate globules, from McKay et al (1996)
Row 6: TEM image of purported "fossils" in ALH 84001 carbonates.
www.cas.usf.edu /~jryan/ALH84001.html   (130 words)

 PROJECTS - Dr. Michael D. Fuller - HIGP   (Site not responding. Last check: 2007-07-20)
Understanding the origin of the magnetite clarifies the paleomagnetic record of ALH 84001, and it is clear that it should have recorded the Martian magnetic field at about 4.0 Gyr and that this field was about an order of magnitude lower than the present geomagnetic field.
Perhaps a little sadly, our work on ALH 84001 reinforces what we might term the boring hypothesis that the magnetic characteristics of this meteorite do not provide evidence of life on Mars because the magnetite does not appear to be biogenic.
In ALH 84001, they form the dominant contribution to the magnetic properties comes from fine near single domain magnetite associated with the carbonate.
www.pgd.hawaii.edu /~mfuller/MFprojects.html   (4154 words)

 ALH 84001: Recent Scientific Papers
Leshin L.A., McKeegan K.D., Carpenter P.K., and Harvey R.P. Oxygen isotopic constraints on the genesis of carbonates from Martian meteorite ALH 84001.
Shearer C.K., Layne G.D., Papike J.J. and Spilde M.N. (1996) Sulfur isotope systematics in alteration assemblages in martian meteorite ALH 84001.
Leshin L.A., McKeegan K.D., Carpenter P.K., and Harvey R.P. (1998) Oxygen isotopic constraints on the genesis of carbonates from Martian meteorite ALH 84001.
www.lpi.usra.edu /lpi/meteorites/alhnpap.html   (15761 words)

 Mars Main Index/Science/Mars Meteorites   (Site not responding. Last check: 2007-07-20)
The striking difference is that this is a meteorite and that it belongs to a small group of meteorites with several features which are characteristic of Mars and completely different from anything else yet discovered in the solar system.
km/sec, ALH 84001 melted partially on the surface, forming the glassy fl fusion crust, which later quickly identified it as a meteorite.
In a few locations such as the Allen Hills (ALH), the ice flow is halted and forced upward There the ice is exposed to constant dry winds and slowly sublimates directly from solid ice to water vapor, leaving meteorites and a few other rocks exposed on the surface.
calspace.ucsd.edu /marsnow/library/science/mars_meteorites1.html   (1515 words)

 Mars Science: ALH 84001 Evidence Grows Weaker
See The ALH 84001 Meteorite for more details.
The second main subject of the final Martian LPSC papers was the seemingly never-ending wrangle over whether Mars Meteorite ALH 84001 does or does not contain significant chemical -- and perhaps microscopic -- evidence of fossilized ancient Martian microbes.
This is hardly surprising, though, since ALH is an igneous rock -- a lump of hardened lava -- and no such rocks have been found even on Earth that contain provable microfossils.
www.spacedaily.com /news/lunarplanet-2000-00c4.html   (1277 words)

 ALH84001 -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-07-20)
Roughly 13,000 years ago, ALH84001 impacted on (The 3rd planet from the sun; the planet on which we live) Earth.
In 1996 ALH 84001 became newsworthy when it was announced that it was believed that the meteorite contained traces of life from Mars, as published in an article in (A particular branch of scientific knowledge) Science by Dr. David McKay of (An independent agency of the United States government responsible for aviation and spaceflight) NASA.
The structures found on ALH84001 are 20-100 (A metric unit of length equal to one billionth of a meter) nanometres in diameters, similar in size to the hypothetical (Click link for more info and facts about nanobacteria) nanobacteria, but smaller than any non-hypothetical earthly lifeform.
www.absoluteastronomy.com /encyclopedia/a/al/alh840012.htm   (285 words)

 StarDate Online | News | Researchers Say Two More Mars Meteorites Show Signs of Life
Because both meteorites are much younger than ALH 84001, they suggest that microscopic life continued to flourish on Mars for billions of years.
After the 1996 announcement, other scientists studied pieces of ALH 84001, and most of their findings refute the evidence of McKay's team.
Critics of the ALH 84001 findings noted that the smallest microbes on Earth were about 100 times larger than the meteorite fossils.
stardate.org /resources/news/mars/199906.html   (609 words)

 Amazon.com: Books: Martian Fossils On Earth?   (Site not responding. Last check: 2007-07-20)
The author states that because this is currently the only book on ALH 84001, no list for further reading is included.
Crisscrossing geology, chemistry, and astronomy, Bortz delves into the hoopla and controversy surrounding the meteorite ALH 84001, which has yielded evidence suggesting the possibility that life once existed on Mars.
He begins with the rock's discovery in Antarctica and goes on to describe the scientific methods used to unlock its secrets and the impact of the discovery on the scientific community.
www.amazon.com /exec/obidos/tg/detail/-/0761302700?v=glance   (748 words)

 [No title]
The outside of ALH 84001 is partially coated with fl fusion crust.
The measured K-Ar puts the age of ALH 84001 as 4.0 B yrs.
The possible evidence of life in ALH 84001 was all found in and around carbonate mineral globules.
lasp.colorado.edu /~rusch/march17/outlinee.htm   (447 words)

 Re: NG and ALH 84001
There is also a snippit about Monahans I assume, it mentions the fact that liquid water was found in a meteorite.
Mike Bernd Pauli HD wrote: > Hello Mike (Farmer) and List, > > Mike was so elated about the color pic of ALH 84001 in the January > 2000 issue of the National Geographic (p.
Next by thread: NG and ALH 84001 + German
www.meteoritecentral.com /messages/msg00168.html   (189 words)

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