Carbonaceous Mighei-like Chondrites are the most common meteorites accounting for ~84% of falls. Chondrites are comprised mostly of Fe- and Mg-bearing silicate minerals (found in both chondrules and fine grained matrix), reduced Fe/Ni metal (found in various states like large blebs, small grains and/or even chondrule rims), and various refractory inclusions (such which exploded into fragments over Murchison, Australia, located ~200 km north of Melbourne, on Sept. 28, 1969. About 82 kg of the Work in progress. A solid natural object reaching a planet’s surface from interplanetary space. Solid portion of a meteoroid that survives its fall to Earth, or some other body. Meteorites are classified as stony meteorites, iron meteorites, and stony-iron meteorites. These groups are further divided according to their mineralogy and were recovered. Eyewitnesses reported smelling something like methanol or pyridine, an early indication that the object might contain Pertaining to C-containing compounds. Organic compounds can be formed by both biological and non-biological (abiotic) processes. material. Subsequent analysis by NASA scientists and a group led by Cyril Ponnamperuma revealed the presence of 6 amino acids commonly found in protein and 12 that did not occur in terrestrial life. All of these amino acids appeared in both dextrorotatory (right-handed) and laevorotatory (left-handed) forms, suggesting that they were not the result of Earthly contamination. The meteorite also contained abiogenic hydrocarbons enriched with a heavy One of two or more atoms with the same atomic number (Z), but different mass (A). For example, hydrogen has three isotopes: 1H, 2H (deuterium), and 3H (tritium). Different isotopes of a given element have different numbers of neutrons in the nucleus. of Element commonly found in meteorites, it occurs in several structural forms (polymorphs). All polymorphs are shown to the left with * indicating that it been found in meteorites and impact structures: a. diamond*; b. graphite*; c. lonsdalite*; d. buckminsterfullerene* (C60); e. C540; f. C70; g. amorphous carbon; h. carbon nanotube*., confirming their extraterrestrial origin. Initial studies suggested that the amino acids in the Murchison meteorite showed no bias between left- and right-handed forms. However, in 1997, John R. Cronin and Sandra Pizzarello of Arizona State University reported finding 7-9% excesses of left-handed versions of four amino acids, a result confirmed independently by another group. More than 70 amino acids have been identified in Murchison altogether. To this organic mixture, in 2001, was added a range of polyols – organic substances closely related to sugars such as glucose.
Some or all content above used with permission from J. H. Wittke.