نتایج جستجو برای: meteorite

تعداد نتایج: 2201  

Journal: :Science 2002
James N Head H Jay Melosh Boris A Ivanov

We performed high-resolution computer simulations of impacts into homogeneous and layered martian terrain analogs to try to account for the ages and characteristics of the martian meteorite collection found on Earth. We found that craters as small as approximately 3 kilometers can eject approximately 10(7) decimeter-sized fragments from Mars, which is enough to expect those fragments to appear ...

Journal: :IBM Journal of Research and Development 2011
Masato Kotsugi Takanori Wakita Toshiyuki Taniuchi Hiroshi Maruyama Chiharu Mitsumata Kanta Ono Motohiro Suzuki Naomi Kawamura Naoki Ishimatsu Masaharu Oshima Yoshio Watanabe Masaki Taniguchi

analysis of an iron meteorite using hard x-ray photoelectron emission microscopy M. Kotsugi T. Wakita T. Taniuchi H. Maruyama C. Mitsumata K. Ono M. Suzuki N. Kawamura N. Ishimatsu M. Oshima Y. Watanabe M. Taniguchi The local structure of an iron meteorite was analyzed using photoemission electron microscopy (PEEM) and hard x-rays. The x-ray absorption fine-structure spectrum was obtained for e...

Journal: :Nature communications 2016
G W Evatt M J Coughlan K H Joy A R D Smedley P J Connolly I D Abrahams

Antarctica contains some of the most productive regions on Earth for collecting meteorites. These small areas of glacial ice are known as meteorite stranding zones, where upward-flowing ice combines with high ablation rates to concentrate large numbers of englacially transported meteorites onto their surface. However, meteorite collection data shows that iron and stony-iron meteorites are signi...

2013
Y. Takano

Introduction: Since the time of Pasteur, the development of biomolecular chirality has remained one of the most important problems with regard to our knowledge concerning chemical evolution. The homochiral amino acids and sugars are essential to the formation, structure, and function of biopolymers and are a defining molecular trait of life on the Earth [1] (cf. asymmetric photochemical process...

Journal: :Science 1998
J L Bada D P Glavin G D McDonald L Becker

Trace amounts of glycine, serine, and alanine were detected in the carbonate component of the martian meteorite ALH84001 by high-performance liquid chromatography. The detected amino acids were not uniformly distributed in the carbonate component and ranged in concentration from 0.1 to 7 parts per million. Although the detected alanine consists primarily of the L enantiomer, low concentrations ...

Journal: :Science 1989
R Zenobi J M Philippoz R N Zare P R Buseck

The distribution of polycyclic aromatic hydrocarbons(PAHs) in the Allende meteorite has been probed with two-step laser desorption/laser multiphoton ionization mass spectrometry. This method allows direct in situ analysis with a spatial resolution of 1 square millimeter or better of selected organic molecules. Spectra from freshly fractured interior surfaces of the meteorite show that PAH conce...

2006
A. J. Timothy Jull

The terrestrial age, or the terrestrial residence time of a meteorite, together with its exposure history provides us with useful insight into the history of the meteorite. It is easy to observe that stony meteorites can weather quickly in humid environments. However, we find that large numbers of meteorites found in semi-arid and arid environments can survive for much longer times. Meteorites ...

Journal: :Science 1996
D S McKay E K Gibson K L Thomas-Keprta H Vali C S Romanek S J Clemett X D Chillier C R Maechling R N Zare

Fresh fracture surfaces of the martian meteorite ALH84001 contain abundant polycyclic aromatic hydrocarbons (PAHs). These fresh fracture surfaces also display carbonate globules. Contamination studies suggest that the PAHs are indigenous to the meteorite. High-resolution scanning and transmission electron microscopy study of surface textures and internal structures of selected carbonate globule...

Journal: :Science 2000
B A Cohen T D Swindle D A Kring

Lunar meteorites represent a more random sampling of lunar material than the Apollo or Luna collections and, as such, lunar meteorite impact melt ages are the most important data in nearly 30 years with which to reexamine the lunar cataclysm hypothesis. Within the lunar meteorite breccias MAC 88105, QUE 93069, DaG 262, and DaG 400, seven to nine different impact events are represented with 40Ar...

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