Asteroids matter

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... 

Except for the moon and the planet Mars, no extraterrestrial body has had pieces of its mass directly examined by scientists in an earthly laboratory. This means that there has been no laboratory sample preparation scheme performed on samples of solid matter from any of the other planets, their moons, comets, or asteroids. And yet we read repeatedly about how scientists have been able to surmise the... 

Star formation and the formation of star systems with planets around them, constantly takes place in dense interstellar clouds. The material present in these clouds is incorporated into the objects that are formed during this process. Pristine or slightly altered organic matter from the cloud from which our solar-system was formed is therefore present in the most primitive objects in the solar system comets, asteroids, and outer solar-system satellites. Pieces of asteroids (and perhaps comets) can be investigated with regards to these components through the analyses of meteorites (and eventually in samples returned from these bodies by spacecraft) in laboratories on Earth. The infall of asteroid and comet material from space may have contributed to the inventory of organic compounds on primordial Earth. 

We have now set the stage for the next two chapters - anhydrous planetesimals and ice-bearing comets and asteroids. These objects contain the organic matter, noble gases, and sometimes ices that we have just learned about, and they provide us with the best record of primitive materials in the solar system. 

Cronin J. R., PizzareUo S., and Cruikshank D. P. (1988) Organic matter in carbonaceous chondrites, planetary satellites, asteroids and comets. In Meteorites and the Early Solar System (eds. J. F. Kerridge and M. S. Matthews). University of Arizona Press, Tucson, pp. 819-857. 

The existence of iron, stony-iron, and achon-drite meteorites implies that many asteroids were heated sufficiently to cause melting and differentiation. The source of this heating is still a matter of debate. Impact melting is inefficient for asteroid-sized bodies, since collisions violent enough to cause melting tend to eject the melted material at greater than the asteroid s escape... 

The cratered surfaces of asteroids and terrestrial planets underscore the importance of impacts for the formation and evolution of the solar system. Early in the history of the solar system such collisions were the mechanism for accretion of planetesimals and finally the planets themselves [1], The effects of these still ongoing collisions are visible from the megascopic down to the submicroscopic length scale, i.e., they range from large impact craters and their ejecta blankets down to shock-metamorphic effects in minerals [2-4]. These effects form as a result of the interaction of strong shock waves with the affected solid matter. 

Anders, E. (1989). Pre-biotic organic matter from comets and asteroids. Nature, 342, 255-7. 

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