Asteroid

Numerous asteroids and smaller debris also exist outside the belt, that is at distances greater than 3.2 AU as well as smaller than 2.2 AU. In particular, the Apollo, Amor, and Atem groups of asteroids are of concern because their orbits cross, or come close to, that of Earth. Smaller objects, less than a few kilometers in diameter, are difficult to detect from Earth, but a collision with one of them could have catastrophic consequences, even if it had a diameter of only a few hundred meters. In 1995, an asteroid about 5 km in length passed between Earth and the Moon it was not detected until days later. It is believed that a large asteroid impacted Earth 65 million years ago and was responsible for the extinction of the dinosaurs and many other species. It is quite possible that a similar event may have caused an even more devastating extinction of many forms of life nearly 250 million years ago (Ward et al, 2000). The possibility that catastrophic impacts may occur again cannot be ruled out (Gehrels, 1994). 

The large number of asteroids in the main belt make it likely that many near encounters and collisions have occurred there over the lifetime of the belt. Orbits of some asteroids were redirected towards the inner as well as the outer regions of the Solar System and many were fragmented into smaller bodies. Smaller particles may have reattached themselves to larger objects, explaining the dust cover of many 

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In fact, even in the solar system, despite the relative strengths of planetary attraction, there are constituents, the asteroids, with very irregular, chaotic behaviour. The issue of chaotic motion in molecules is an issue that will appear later with great salience.)... 

J. Wisdom. The origin of the Kirkwood gaps A mapping for asteroidal motion near the 3/1 commensurability. Astr. J., 87 577-593, 1982. 

Wisdom, J. The Origin of the Kirkwood Gaps A Mapping for Asteroidal Motion Near the 3/1 Commensurability. Astron. J. 87 (1982) 577-593 Tuckerman, M., Martyna, G. J., Berne, J. Reversible Multiple Time Scale Molecular Dynamics. J. Chem. Phys. 97 (1992) 1990-2001 Tuckerman, M., Berne, J. Vibrational Relaxation in Simple Fluids Comparison of Theory and Simulation. J. Chem. Phys. 98 (1993) 7301-7318 Humphreys, D. D., Friesner, R. A., Berne, B. J. A Multiple-Time Step Molecular Dynamics Algorithm for Macromolecules. J. Chem. Phys. 98 (1994) 6885-6892... 

Palladium was named after the asteroid Pallas, which was discovered at about the same time. Pallas was the Greek goddess of wisdom. 

Cerium was named for the asteroid Ceres, which was discovered in 1801. The element was discovered two years later in 1803 by Klaproth and by Berzelius and Hisinger. In 1875 Hillebrand and Norton prepared the metal. 

There is also the promise of finding large amounts of deep methane formed not from biomass but by some abiological processes from carbonates or even carbides formed from carbon-containing asteroids that hit the earth over the ages under the harsh prebiological conditions of our planet. 

What a storyi Fullerenes formed during the ex plosion of a star travel through interstellar space as passengers on a comet or asteroid that eventually smashes into Earth Some of the fullerenes carry pas sengers themselves—atoms of helium and argon from the dying star The fullerenes and the noble gas atoms silently wait for 251 million years to tell us where they came from and what happened when they got here... 

Eig. 5. The Widmanstatten pattern ia this poHshed and etched section of the Gibbeon iron meteorite is composed of iatergrown crystals of kamacite and taenite, NiFe phases that differ ia crystal stmcture and Ni content. Ni concentration gradients at crystal boundaries ia this 3-cm-wide sample can be used to estimate the initial cooling rates and corresponding size of the asteroid from which the meteorite was derived. 

Stony Irons. The stony iron meteorites are composed of substantial iron and siUcate components. The paHasites contain cm-sized ohvine crystals embedded ia a soHd FeNi metal matrix and have properties consistent with formation at the core mantle boundary of differentiated asteroids. The mesosiderites are composed of metal and siUcates that were fractured and remixed, presumably ia the near-surface regions of their parent bodies. 

In a first step, JS ocardia asteroides selectively oxidizes only (3)-pantolactone to ketopantolactone (19), whereas the (R)-pantolactone remains unaffected (47). The accumulated ketopantolactone is stereospecificaHy reduced to (R)-pantolactone in a second step with Candidaparapsilosis (product concentration 72 g/L, 90% molar yield and 100% ee) (48). Racemic pantolactone can also be converted to (R)-pantolactone by one single microbe, ie, Jiodococcus erythropolis by enantioselective oxidation to (3)-pantolactone and subsequent stereospecific reduction in 90% yield and 94% ee (product concentration 18 g/L) (40). 

Silver, L.T., and Schultz, P. (Eds.) Geological Implications of Impacts of Large Asteroids and Comets on the Earth, pp. 1-528, Special Paper 190, The Geological Society of America, Boulder, Colorado, 1982. 

In 1803, in the course of his study of platinum, Wollaston isolated and identified palladium from the mother liquor remaining after platinum had been precipitated as (NH4)2PtCl6 from its solution in aqua regia. He named it after the newly discovered asteroid, Pallas, itself named after the Greek goddess of wisdom (ytaXXd iov, palladion, of Pallas). 

In 1751 the Swedish mineralogist, A. F. Cronstedt, discovered a heavy mineral from which in 1803 M. H. Klaproth in Germany and, independently, i. i. Berzelius and W. Hisinger in Sweden, isolated what was thought to be a new oxide (or earth ) which was named ceria after the recently discovered asteroid, Ceres. Between 1839 and 1843 this earth, and the previously isolated yttria (p. 944), were shown by the Swedish surgeon C. G. Mosander to be mixtures from which, by 1907, the oxides of Sc, Y, La and the thirteen lanthanides other than Pm were to be isolated. The small village of Ytterby near Stockholm is celebrated in the names of no less than four of these elements (Table 30.1). 

The first experiments with the thermal electric engine were conducted in Russia in 1929 by its inventor, Valentin P. Glushko, who later became a world-famous authority in rocket propulsion. For more than forty years, the United States and Russia have devoted many resources to research and development of various kinds of EREs. First tested in space by the Russians in 1964, these engines have found some limited applications in modern space technology. For more than two decades Russian weather and communication satellites have regularly used electric rocket engines for orbital stabilization. The first spacecraft to employ ERE for main propulsion was the American asteroid exploration probe Deep Space 1, launched in 1998. The performance of... 

Our solar system consists of the Sun, the planets and their moon satellites, asteroids (small planets), comets, and meteorites. The planets are generally divided into two categories Earth-like (terrestrial) planets—Mercury, Venus, Earth, and Mars and Giant planets—Jupiter, Saturn, Uranus, and Neptune. Little is known about Pluto, the most remote planet from Earth. 

Palladium and platinum are the longest known and most studied of the six platinum metals [1-11], a reflection of their abundance and consequent availability. Platinum occurs naturally as the element, generally with small amounts of the other platinum metals. It was used as a silver substitute by Colombian Indians and first observed there by Ulloa (1736), who called it platina del Pinto ( little silver of the Pinto river ) but the first sample was actually brought to Europe in 1741 by Charles Wood, Assay Master of Jamaica. Palladium was isolated in 1803 by W.H. Wollaston, who was studying the aqua regia-soluble portion of platinum ores (he announced his discovery by an anonymous leaflet advertising its sale through a shop in Soho) and named it after the newly discovered asteroid Pallas [12],... 

Water and carbon play critical roles in many of the Earth s chemical and physical cycles and yet their origin on the Earth is somewhat mysterious. Carbon and water could easily form solid compounds in the outer regions of the solar nebula, and accordingly the outer planets and many of their satellites contain abundant water and carbon. The type I carbonaceous chondrites, meteorites that presumably formed in the asteroid belt between the terrestrial and outer planets, contain up to 5% (m/m) carbon and up to 20% (m/m) water of hydration. Comets may contain up to 50% water ice and 25% carbon. The terrestrial planets are comparatively depleted in carbon and water by orders of magnitude. The concentration of water for the whole Earth is less that 0.1 wt% and carbon is less than 500 ppm. Actually, it is remarkable that the Earth contains any of these compounds at all. As an example of how depleted in carbon and water the Earth could have been, consider the moon, where indigenous carbon and water are undetectable. Looking at Fig. 2-4 it can be seen that no water- or carbon-bearing solids should have condensed by equilibrium processes at the temperatures and pressures that probably were typical in the zone of fhe solar... 

As evidenced by their low abundances, carbon compounds, water, and other volatiles such as nitrogen compounds were probably not significantly abundant constituents of the bulk of the solids that formed near the Earth. Many of the carriers of these volatiles condensed in cooler, more distant regions and were then scattered into the region where the Earth was forming. Eragments of comets and asteroids formed in the outer solar system still fall to Earth at a rate of 1 x 10 kg/yr and early in the... 

After planetary accretion was complete there remained two groups of surviving planetesimals, the comets and asteroids. These populations still exist and play an important role in the Earth s history. Asteroids from the belt between Mars and Jupiter and comets from reservoirs beyond the outer planets are stochastically perturbed into Earth-crossing orbits and they have collided with Earth throughout its entire history. The impact rate for 1 km diameter bodies is approximately three per million years and impacts of 10 km size bodies occur on a... 

Devonian 400 Myr Continents collide at end of period. Asteroid probably collides with Earth. Diversification of bony and cartilaginous fishes trilobites diversify origin of ammonoids, amphibians, insects first forests. Mass extinction at end of period (ca. 75% of species disappear)... 

Ligand 92 was readily prepared by reaction of (+)-pinocarvone with 1-phenacylpyridinium iodide. The authors similarly prepared corresponding 5,6-dihydro-1,10-phenanthrolines derived from (+)-pinocarvone and a tetrahydroquinolone (structure 93, [127]) and obtained up to 81% in the palladium-catalyzed test reaction. Chelucci et al. [ 128] reported the synthesis of chiral Ci-symmetric 1,10-phenanthrolines incorporated in asteroid backbone. Structure 94 derived from 5o -cholestan-4-one in Scheme 51, allowed very high yield and up to 96% ee using BSA and tetrabutylammonium fluoride to generate the malonate anion. 

Goad (40) and others have extensively reviewed coelenterate and echinoderm sterols including the saponins found in starfish and sea cucumbers. Cholesterol is a common sterol in most families, except for gorgonians and zoanthids some soft corals contain polyhydroxylated sterols. The amount of variation associated with phylogeny is illustrate in the echinoderms by the fact that crinoids, ophuiroids, and echinoids contain A 5 sterols while holothuriodeans and asteroids contain A 7 sterols. Some classes contain uniquely structured sterols. 

Granular matter is all around us. It ranges from natural materials such as sand and asteroids to artificial materials such as pharmaceutical tablets and dry cereal. There is great and practical interest in static granular matter from the standpoint, for... 

C. Jaffe, S. D. Ross, M. W. Eo, J. Marsden, D. Farrelly, andT. Uzer, Statistical theory of asteroid escape rates, Phys. Rev. Lett. 89, 011101 (2002). 

Efforts to get Patterson a Nobel Peace Prize proved unsuccessful, despite Saul Bellow s frequent nominations. However, Patterson was elected to the National Academy of Science Asteroid 2511 was named for him and he won both the Goldschmidt Medal of the Geochemical Society and the 150,000 John and Alice Tyler Prize for Environmental Achievement, the highest award for environmental science. Finally, with retirement nearing, he agreed to become a Caltech professor. 

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