Solar System

Planetary Science is the branch of knowledge benefiting most as a result of the space age. In less than half a century, the field has been revolutionized by the influx of new images, observations, and other forms of data. Most planets and their larger satellites have been transformed from telescopic objects to individual worlds. Each has revealed a distinctive geological pedigree. New twists on well-known evolutionary processes are seen, and totally unanticipated phenomena are revealed every time a spacecraft visits a planet. What was ‘‘planetary astronomy’’ in one generation has become ‘‘comparative planetology.’’ Technological developments such as adaptive optics, large-mirrored telescopes, and infrared (IR) array detectors have revitalized our observatories. These new tools enable significant, but parallel, progress to be made from the ground. Computers allow numerical experiments to test theories and to run simulations where a solution of the analytic equations is impossible.