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The results of thorough bacterialpaleontological study of the Orgueil meteorite are presented in this illustrated Atlas of microfossils (both prokaryotic and eukaryotic) found within freshly fractured interior surfaces of the meteorite. More than 60 images obtained with Scanning Electron Microscope are presented.
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Life-bearing meteors, asteroids, comets and frozen bodies of water which had been ejected from Mars or other planets via bolide impact may have caused the Cambrian Explosion of life on Earth 540 million years ago. Reviewed in support of this theory are historical and worldwide reports of blood, gore, flesh and a variety of organisms raining from clear skies on warm days along with freezing rains and ice and sometimes embedded in ice and which a 2008 report in the International Journal of Astrobiology linked to comets and celestial events. Numerous reports have documented, within meteors, fossilized organisms resembling fungi, algae, and diatoms. In 1880 specimens resembling fossilized crinoids, corals and sponges were identified within an assemblage of meteorites that had fallen to Earth and investigators speculated that evolution may have occurred in a similar fashion on other planets. Russian scientists have reported that mosquito larvae, the majority of seeds from a variety of plants, and fish eggs and embryos from crustaceans develop and reproduce normally after 7 to 13 months exposure to space outside the ISS and could travel to and from Earth and Mars and survive. Investigators have identified specimens on Mars that resemble stromatolites, bacterial mats, algae, fungi, and lichens, and fossils resembling tube worms, Ediacarans, Metazoans and other organisms including those with eyes and multiple legs. McKay speculated that evolution may have taken place more rapidly on Mars and experienced a "Cambrian Explosion" in advance of Earth. Eight hundred million years ago an armada of asteroids, comets and meteors more numerous and several times more powerful than the Chicxulub impact, invaded the inner solar system and struck the Earth-Moon system. It is highly probable Mars was also struck and massive amounts of life-bearing debris was cast into space. Genetic studies indicate the first metazoans appeared on Earth 750 to 800 million years ago soon after this impacting event. Given the relatively sudden "explosive" appearance of complex life with bones, brains, and modern eyes, as well as those that were bizarre and quickly became extinct, and given there are no antecedent intermediate forms and that previous life forms consisted of only 11 cell types prior to the Cambrian Explosion, the evidence, in total, supports the theory that life on other planets and Mars may have been transported to Earth 800 million years ago and contributed to the Cambrian Explosion.
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Interest in mineral-microbe interaction has grown enormously over recent decades, providing information in a puzzle-like manner which points towards an ever increasingly intimate relationship between the two; a relationship that can be truly termed co-evolution. Clay minerals play a very central role in this co-evolving system. Some 20 years ago, clay scientists looked at clay mineral- microbe studies as a peripheral interest only. Now, can clay scientists think that they understand the formation of clay minerals throughout geological history if they do not include life in their models? The answer is probably no, but we do not yet know the relative weight of biological and inorganic factors involved in driving clay-mineral formation and transformation. Similarly, microbiologists are missing out important information if they do not investigate the influence and modifications that minerals, particularly clay minerals, have on microbial activity and evolution. This review attempts to describe the several points relating clay minerals and microorganisms that have been discovered so far. The information obtained is still very incomplete and many opportunities exist for clay scientists to help to write the real history of the biosphere.
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Using visual observations that were reported 140 years ago in the Comptes Rendus de l'Academie des Sciences de Paris, we have determined the atmospheric trajectory and the orbit of the Orgueil meteorite, which fell May 14, 1864, near Montauban, France. Despite the intrinsic uncertainty of visual observations, we were able to calculate a reasonably precise atmospheric trajectory and a moderately precise orbit for the Orgueil meteoroid. The atmosphere entry point was similar to 70 km high and the meteoroid terminal point was similar to 20 km high. The calculated luminous path was similar to 150 km with an entry angle of 20 degrees. These characteristics are broadly similar to that of other meteorites for which the trajectory is known. Five out of six orbital parameters for the Orgueil orbit are well constrained. In particular, the perihelion lies inside the Earth's orbit (q similar to 0.87 AU), as is expected for an Earth-crossing meteorite, and the orbital plane is close to the ecliptic (i similar to 0 degrees). The aphelion distance (Q) depends critically on the pre-atmospheric velocity. From the calculated atmospheric path and the fireball duration, which was reported by seven witnesses, we have estimated the pre-atmospheric velocity to be larger than 17.8 km/sec, which corresponds to an aphelion distance Q larger than 5.2 AU, the semi-major axis of Jupiter orbit. These results suggest that Orgueil has an orbit similar to that of Jupiter-family comets (JFCs), although an Halley-type comet cannot be excluded. This is at odds with other meteorites that have an asteroidal origin, but it is compatible with 140 years of data-gathering that has established the very special nature of Orgueil compared to other meteorites. A cometary origin of the Orgueil meteorite does not contradict cosmochemistry data on CII chondrites. If CII chondrites originate from comets, it implies that comets are much more processed than previously thought and should contain secondary minerals. The forthcoming return of cometary samples by the Stardust mission will provide a unique opportunity to corroborate (or contradict) our hypothesis.