Asteroids Caused The Early Inner Solar System Cataclysm

University of Arizona and Japanese scientists are convinced that evidence at last settles decades-long arguments about what objects bombarded the early inner solar system in a cataclysm 3.9 billion years ago.

Ancient main belt asteroids identical in size to present-day asteroids in the Mars-Jupiter belt -- not comets -- hammered the inner rocky planets in a unique catastrophe that lasted for a blink of geologic time, anywhere from 20 million to 150 million years, they report in the Sept. 16 issue of Science.

However, the objects that have been battering our inner solar system after the so-called Late Heavy Bombardment ended are a distinctly different population, UA Professor Emeritus Robert Strom and colleagues report in the article, "The Origin of Planetary Impactors in the Inner Solar System."


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http://www.sciencedaily.com/releases/2005/09/050917091640.htm