Orgueil (meteorite)

Orgueil is a scientifically important carbonaceous chondrite meteorite that fell in southwestern France in 1864.

Orgueil
TypeChondrite
ClassCarbonaceous chondrite
GroupCI1
CountryFrance
RegionMidi-Pyrénées
Coordinates43°53′N 1°23′E[1]
Observed fallYes
Fall dateMay 14, 1864
TKW14 kg
Original painting of an individual fragment from the Orgueil meteorite

History

It fell on May 14, 1864, a few minutes after 20:00 local time, near Orgueil in southern France. About 20 stones fell over an area of 5-10 square kilometres. A specimen of the meteorite was analyzed that same year by François Stanislaus Clöez, professor of chemistry at the Musée d'Histoire Naturelle, who focused on the organic matter found in this meteorite. He wrote that it contained carbon, hydrogen, and oxygen, and its composition was very similar to peat from the Somme valley or to the lignite of Ringkohl near Kassel. An intense scientific discussion ensued, continuing into the 1870s, as to whether the organic matter might have a biological origin.[2]

Composition and classification

Orgueil is one of five known meteorites belonging to the CI chondrite group (see meteorites classification), and is the largest (14 kilograms (31 lb)). This group is remarkable for having a composition that is essentially identical to that of the sun, excluding gaseous elements like hydrogen and helium. Notably though, the Orgueil meteor is highly enriched in (volatile) mercury - undetectable in the solar photosphere, and this is a major driver of the "mercury paradox" that mercury abundances in meteors do not follow its volatile nature and isotopic ratios based expected behaviour in the solar nebula [3][4].

Because of its extraordinarily primitive composition and relatively large mass, Orgueil is one of the most-studied meteorites. One notable discovery in Orgueil was a high concentration of isotopically anomalous xenon called "xenon-HL". The carrier of this gas is extremely fine-grained diamond dust that is older than the solar system itself, known as presolar grains.

In 1962, Nagy et al. announced the discovery of 'organised elements' embedded in the Orgueil meteorite that were purportedly biological structures of extraterrestrial origin. These elements were subsequently shown to be either pollen (including that of ragwort) and fungal spores (Fitch & Anders, 1963) that had contaminated the sample, or crystals of the mineral olivine.

The hoax

In 1965, a fragment of the Orgueil meteorite, kept in a sealed glass jar in Montauban since its discovery, was found to have a seed capsule embedded in it, whilst the original glassy layer on the outside remained apparently undisturbed.[5] Despite great initial excitement, the seed capsule was shown to be that of a European rush, glued into the fragment and camouflaged using coal dust. The outer "fusion layer" was in fact glue. Whilst the perpetrator is unknown, it is thought that the hoax was aimed at influencing 19th century debate on spontaneous generation by demonstrating the transformation of inorganic to biological matter.

Claim of fossils
Main article: Journal of Cosmology § Hoover paper controversy

Richard B. Hoover of NASA has claimed that the Orgueil meteorite contains fossils, some of which are similar to known terrestrial species.[6] Hoover has previously claimed the existence of fossils in the Murchison meteorite. However, NASA has formally distanced itself from Hoover's claims and his lack of expert peer-reviews.[7]

gollark: I felt it was worth mentioning generally, though.
gollark: Yes, I know.
gollark: Technically, the answer to "what comes next" questions can be basically whatever you want.
gollark: mafs.
gollark: Heresy!

See also

References
  1. Meteoritical Bulletin Database: Orgueil
  2. Burke, John G. (1986). Cosmic Debris: Meteorites in History. Berkeley and Los Angeles, California: University of California Press. pp. 168–169. ISBN 0-520-05651-5.
  3. Lauretta, D.S., Devouard, B., Buseck, P.R., (1999). The cosmochemical behavior of mercury. Earth and Planetary Science Letters, 171, 35-47
  4. Meier, M.M.M., Cloquet, C., Marty, B., (2015). Mercury (Hg) in meteorites: Variations in abundance, thermal release profile, mass-dependent and mass-independent isotopic fractionation. Geochimica et Cosmochimica Acta, 182, 55–72
  5. "The Orgueil Meteorite, 1864". The Museum of Hoaxes. Retrieved 2014-04-16.
  6. Hoover, Richard B. (2011). "Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites: Implications to Life on Comets, Europa, and Enceladus" (PDF). Journal of Cosmology. 13. Retrieved 2011-03-05.
  7. Kerry Sheridan (7 March 2011). "NASA shoots down alien fossil claims". ABC News. Retrieved 2011-03-07.

Further reading
  • Nagy B, Claus G, Hennessy DJ (1962) Organic Particles Embedded in Minerals in Orgueil and Ivuna Carbonaceous Chondrites. Nature 193 (4821) p. 1129
  • Fitch FW, Anders E (1963) Organized Element - Possible Identification in Orgueil Meteorite. Science 140 (357) p. 1097
  • Gilmour I, Wright I, Wright J 'Origins of Earth and Life', The Open University, 1997, ISBN 0-7492-8182-0
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.