2 edition of Studies on terrestrial contaminants in meteorites found in the catalog.
Studies on terrestrial contaminants in meteorites
References: p. 405-407
|Other titles||Bacteriology of meteorites|
|Statement||[by] George Claus [and] Peter P. Madri|
|Series||Annals of the New York Academy of Sciences, v. 196, Annals of the New York Academy of Sciences -- v. 196|
|Contributions||Madri, Peter P|
|The Physical Object|
|Number of Pages||407|
compounds could be the products of microbial and terrestrial contamination. With the wealth of literature available on the extraterrestrial nature of organics in meteorites this approach is improbable, however, we feel that as a preliminary null hypothesis it is a baseline approach that is worth investiga-tion. The discussion on whether amino acids in meteorites were racemic (with equal amounts of L and D forms) or non-racemic (with a preference) began in the s and continued through the s (e.g. Mueller , Nagy ), but again results suggested the dominance of L forms was caused by terrestrial contamination and analytical artefacts.
The “freshness” of meteorites is important to meteorite studies. The possibility of terrestrial contamination and weathering effects needs to be carefully examined for many finds. For meteorite finds, it is useful to indicate semi-quantitatively the degree of terrestrial weathering. Two classification schemes are widely used. Nevertheless, terrestrial contamination still cannot be ruled out entirely. For researchers engaged in meteorite studies, the preferred means for acquiring samples is to collect them in the field. This approach has been far more productive in terms of numbers of meteorites and has led to major searches in those places in the world where.
Methane, a potential sign of primitive life, has been found in meteorites from Mars, adding weight to the idea that life could live off . Of meteorites observed to fall between and in densely populated areas of Japan, India, Europe, and North America, 3 were from Mars, and so the ratio of martian meteorites to total meteorites is roughly This number is very approximate.
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Get this from a library. Studies on terrestrial contaminants in meteorites: Part II. Bacteriology of meteorites. [George Claus; Peter P Madri]. Lajos Keszthelyi, in Advances in BioChirality, Extraterrestrial origin.
In a careful study Engel and Macko found that the ratio of concentrations of d/l alanine was and d/l glutamic acid was in samples from the Murchison meteorite .The extraterrestrial origin of the amino acids studied and, consequently, of the excess of l-amino acids was supported with isotopic.
The fragment of Murchison meteorite investigated in this study was already analyzed for amino acids, and it was established that this Murchison meteorite fragment experienced minimal terrestrial contamination based on a near-racemic (d ∼ l) mixture of the common biological Studies on terrestrial contaminants in meteorites book acid alanine.
Large fractions of the meteorites were used for Cited by: 9. Two new chemical studies produce evidence that significant amounts of organic compounds in Martian meteorite found in Antarctica are terrestrial contamination, not possible traces of past life on Author: John Noble Wilford.
Extended Data Figure 2 A comparison of meteorite find environments can be used as a diagnostic tool to assess terrestrial contamination. Chlorine concentrations in hot desert, cold desert and non Cited by: Terrestrial contamination is a serious problem for studies of extraterrestrial materials.
To avoid such contamination, the team developed new techniques to prepare the samples with. Because, aside from the samples returned from the Moon, meteorites are the only samples of extraterrestrial matter available for study in terrestrial laboratories, they play a major role in our ideas about the chemical composition of Solar System material.
Also, because most meteorites are much older than the oldest known lunar and terrestrial. To avoid the possible terrestrial contaminants picked up by the meteorite in Antarctica, the team obtained their samples from the solid interior volume of the rock.
They found that cracks within the meteorite contain orange-tinted carbonate globules. So, the variability in isotope ratios seen in Mars meteorites was chalked up to terrestrial contamination or alteration by the Red Planet's atmosphere as.
One of the most famous is the Nakhla meteorite, which, according to some accounts, killed a dog when it came down in Egypt in That raises another problem we often face with meteorites: the possibility of terrestrial contamination, particularly when most of them were exposed to Earth for quite a while before they were found.
The Murchison meteorite is one of the most studied of all meteorites [according to whom?] due to its mass (over kg or lb) and the fact that it was an observed fell in Australia in near Murchison, belongs to a group of meteorites rich in organic compounds. In Januarycosmochemists reported that the oldest material found on Earth to date is the.
Terrestrial contamination is a serious problem for studies of extraterrestrial materials. To avoid such contamination, the team developed new techniques to prepare the samples with. For example, they used silver tape in an ELSI clean lab to pluck off the tiny carbonate grains, which are about the width of a human hair, from the host meteorite.
Studies of 8-aminoadenosine, as a potential cancer therapeutic, have shown that this compound is known to inhibit transcription by multiple mechanisms so that the presence of 6,8-diaminopurine (8-aminoadenine) in meteorites is highly unlikely to be the result of terrestrial biological contamination.
History. The potential problem of lunar and planetary contamination was first raised at the International Astronautical Federation VIIth Congress in Rome in In the U.S.
National Academy of Sciences (NAS) passed a resolution stating, “The National Academy of Sciences of the United States of America urges that scientists plan lunar and planetary studies with great. Additional evidence came from research to further rule out the possibility of terrestrial contamination as a source of these molecules.
The team analyzed an eight-kilogram (pound) sample of ice from Antarctica, where most of the meteorites in the study were found. The amounts of nucleobases found in the ice were much lower than in the. Get this from a library. Studies on terrestrial contaminants in meteorites: Part II.
Bacteriology of meteorites. [George W Claus; Peter P Madri]. The Imaging of Terrestrial Microbial Contamination of Meteorites INTRODUCTION The debate over the McKay et al. () hypothesis that Martian life forms were pre-served in meteorite ALH has been well documented and recent papers on the nature of biogenic magnetite within this meteorite ensure that this will continue [1,2].
Almost. Abstract. Isotopic studies of meteorites provide the fundamental data for determining how the terrestrial planets, including Earth, accreted.
Over the past few years there have been major advances in our understanding of both the timescales and processes of terrestrial planet accretion, largely as a result of better definition of initial solar system abundances of short.
That means scientists must be extra vigilant in identifying and assessing the effects of terrestrial organic contamination of meteoritic samples. Infrared Spectroscopy The paper, “ Mid-infrared Study of Stones from the Sutter’s Mill Meteorite,” was published online in the March, issue of the journal Meteoritics and Planetary Science.
"At the start of this project, it looked like the nucleobases in these meteorites were terrestrial contamination — these results were a very big surprise for me," study co-author Michael.
Fantastic complete slice of Mars meteorite, of the recent NWA classification, classified as Martian Shergottite after all the corresponding studies and analyses. It shows low signs of terrestrial metamorphism, which increases its scientific value due to the low contamination it has suffered on contact with other materials from our planet.
Although meteorites from Mars .Life-Forms in Meteorites and the PROBLEM-Of Terrestrial Contamination: a Study in Methodology Tasch, Paul; Abstract. Publication: Annals of the New York Academy of Sciences. Pub Date: September DOI: /jtbx Bibcode: NYASAT.Radiogenic and cosmic-ray exposure ages of meteorites, their orbits and parent bodies Dynamical studies of asteroidal and cometary orbits and their relation to the origin of meteorites Origine cométaire des meteorites déduite de reffet du rayonnement cosmique solaire dans les meteorites et la conséquence de cette origine The LL-group chondrites.