AY 101 Lecture Notes - Lecture 10: Kuiper Belt, Interstellar Cloud, Oort Cloud
Document Summary
Planetesimals are small objects that started out as tiny particles that grew over time through condensation. Planetesimals are: generally small, only a few miles or less in size, often non-spherical in shape owing to their low mass and gravity, found in large numbers in specific regions of the solar system. Planetesimals are believed to be the building blocks of larger worlds. The ones we see today are leftovers from the formation of the planets. Near the sun, planetesimals are made mostly of rock and metal. Far from the sun, ices became an additional major constituent of planetesimals, due to lower temperatures. We call an icey planetesimal a comet nucleus. Why are temperatures lower in the outer solar system as compared to the inner solar system: because the amount of heat received from the sun decreases inversely with the square of the distance from the sun.
