Is there an approximation on when scientists first found out about certain elements on asteroids?
What about gold in particular?
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The first asteroid (Ceres) was discovered on 1801. Initial studies on asteroids were primarily on positional parameters and nature of orbit. The first ever attempt on predicting the composition of asteroids was done by Watson et.al. on 1941 but due to limited technology and knowledge, the findings were found to be inconclusive. In the 1950s, with the development of instrumental telemetry, effort were given in studying asteroid curves, rotational periods, body shapes and pole orientation. Then in 1970, the first ever true study on asteroid composition was made whose findings were made official. McCord et.al. studied asteroid 4 Vesta which proved that its composition were similar to Nuevo Laredo basaltic achondrite. More studies were done on the spectral of minerals (Burns et.al. on 1970 and Adams et.al. 1974-75). Subsequently, the first study on meteorites were done by Salisbury et.al. on 1975 and Gaffey et.al. on 1976. An asteroid taxonomy were also made by Tholen(1984) and Tholen-Barucci(1989).
In the late 1970s, two scientists named Jonathan Gredie and Edward Tedesco proposed that there is a relationship between asteroid composition and distance from sun. This proposal were further supported though observations and models made by another astronomer John Lewis. He confirmed that asteroid composition changes as a function of temperature and hence distance from sun. Therefore, all asteroids do not have same composition.
In 2005, 25143 Itokawa became the first asteroid from which samples were captured and brought to Earth for analysis. The Japanese spacecraft Hayabusa touched down twice on the asteroid and collected a small amount of dust despite the failure of the mechanism designed for the purpose. It delivered the sample to Earth on 13 June 2010. It was was discovered Sept. 26, 1998 by the Lincoln Laboratory Near-Earth Asteroid Research Team at Socorro, New Mexico.
According to NASA, 50 000 meteorites have fallen on Earth and 99.8 percent of them come from asteroids. The remainder come from the Moon and Mars.
The Kaba meteorite (carbonaceous chondrite) fell near the village of Kaba in Hungary, in 1857. The first chemical analysis of the meteorite was undertaken by German chemist Friedrich Wöhler, in 1858. It was the first case of organic material being discovered from an extraterrestrial origin, when urea was discovered on the meteorite.
In 1802 only three minerals had been identified in meteorites. By the 1960s that had increased to 40-50 minerals.
In meteorites, two or three dozen minerals can be identified with a hand lens or petrographic microscope. The rest are opaque or too small and don’t yield to examination under transmitted light optical microscopes. They require sophisticated equipment and techniques to identify such as reflected light microscopy, x-ray diffraction, electron microprobe analysis, and electron microscopy.
The most abundant minerals in meteorites are pyroxene, olivine, plagioclase feldspar,kamacite and taenite (an iron-nickel mixture), and small amounts of troilite, schreibersite, and cohenite. The silicate minerals—pyroxenes, olivines, and feldspars—dominate the stony meteorites. Metals—kamacite and taenite—along with small amounts of schreibersite and cohenite dominate iron meteorites.