Asteroids and Comets

FEB 01, 1985

The formation of the Sun and planets left remnants, such as the million objects larger than 1 km between the orbits of Mars and Jupiter, that give us a look at the original building blocks of the solar system.

DOI: 10.1063/1.880999

Tom Gehrels

Asteroids that orbit the Sun in a belt between the orbits of Mars and Jupiter are well known. A few other asteroids cross Earth’s orbit, and, from time to time, one collides with our planet, as figure 1 so clearly indicates. What are they made of? How did they originate? We suspect that material much like the asteroids played a part in the origin of the solar system—can we see similar forces at work elsewhere?

References

1. Theories of formation of stars and planets are described in the Protostars and Planets books, T. Gehrels, ed., 1978;
D. C. Black, M. S. Matthews, eds., 1985, U. of Ariz. P., Tucson.
2. E. M. Shoemaker, J. G. Williams, E. F. Helin, R. F. Wolfe, in Asteroids, T. Gehrels, ed., U. of Ariz. P., Tucson (1979).
3. R. Ganapathy, Science 216, 885 (1982); https://doi.org/SCIEAS
W. Alvarez, F. Asaro, H. V. Michel, Science 216, 886 (1982).https://doi.org/SCIEAS
4. L. W. Alvarez, W. Alvarez, F. Asaro, H. Michel, Science 208, 1095 (1980); https://doi.org/SCIEAS
R. Ganapathy, Science 209, 921 (1980).https://doi.org/SCIEAS
5. C. Emiliani, E. B. Kraus, E. M. Shoemaker, Earth Planet. Sci. Letters 55, 317 (1981).
6. J. B. Pollack, O. B. Toon, T. P. Ackerman, C. P. McKay, Science 219, 287 (1983).https://doi.org/SCIEAS
7. D. A. Russell, R. Seguin, Syllogeus, No. 37, Nat. Museum of Natural Sciences, Ottawa (1982).

More about the Authors

Tom Gehrels. University of Arizona, Tucson.