•Small bodies are not geologically active
•They provide “fossil” record of early
solar system
–Asteroids
•Mostly from region between Mars and Jupiter
•Left over small debris from accretion, never
assembled into a large planet
•Meteorites come mostly from asteroids
–Comets
•“Stored” on large elliptical orbits
beyond planets
•Thought to be “planetesimals” from Jovian
planet region, almost ejected
from solar system in its early history
•Meteorites provide only samples besides Apollo
–With sample in hand, can perform very detailed
analysis: detailed chemistry; radioisotope age; other isotope
info
–