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In the past 100 years the science of meteoritics has matured to a highly
interdisciplinary field. Especially, the developments during the last decades of the 20th
century have revolutionized the young discipline, bringing in new fields, e.g. cosmochemistry,
planetology, nuclear science, radio-astronomics, as well as data obtained by space flights
and space probes. However, we are just beginning to explore our solar system, and meteorites
may help us a lot in achieving this goal since they actually represent samples of other
worlds available for research. |
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Meteoritics meets the Space Age
The advances in analytical chemistry during the early 20th century marked another milestone
in the progress of meteoritics. In 1916, George T. Prior, the Keeper of Minerals of the British
Museum, came up with a brand-new classification scheme based upon the principal minerals found
in each meteorite, and the ratio of oxidized iron to iron metal for chondrites, the calcium
content for achondrites, and the nickel content for iron meteorites.
Prior's classification scheme remained more or less unchanged, and in use until the
late 60s of the 20th century. The late 60s didn't just bring about Woodstock and the Sexual
Revolution, but also a profound technological revolution, and the Space Age. Brand-new
instruments and analytical devices, such as the electron microscope, and the electron
microprobe would allow a new generation of meteoriticists to determine the elemental
compositions of meteorites, and their minerals with an accuracy never attained before.
Trace elements in iron meteorites, for example, could now be determined in great detail,
resulting in a new chemical classification system for this class of meteorites.
The progress in nuclear science during the last decades also provided great new devices and tools
for the study of meteorites. The isotopic compositions of various meteorites could now be determined,
leading to the discovery of oxygen-isotope-ratios as kind of a fingerprint for certain meteorite
groups and clans, linking them directly to their respective parent bodies. On the other hand, the
advance in optical astronomy provided meteoritics with the possibility to compare selected
reflectance spectra of planets and asteroids with the reflectance spectra of certain meteorite groups
and clans, thus providing evidence for their specific origins.
Last but not least, the various space missions such as the Apollo program, the Viking Landers,
the Pathfinder Mission, and the ongoing robotic research by the rovers Spirit and Opportunity on
Mars provided modern meteoritics with the hard proof for the fact that we actually have samples of
the Moon and the planet Mars on Earth and available for study - in form of the so-called planetary
meteorites. These samples are available for research without having to invest into most expensive
space missions first, and in the case of the Red Planet they are currently the only samples availabe
for study on Earth. The science of meteoritics which started off as kind of an orphan of natural
science has now literally become a spearhead of planetology and planetary science, and there's much
more to come. |
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False-Color BSE Image - NWA 1195
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© A. Irving & S. Kuehner
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Sojourner Studying Mars Rock Yogi
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©
NASA/JPL
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