AY 101 Lecture Notes - Lecture 11: Terrestrial Planet, Comet Nucleus, Lunar Mare
Document Summary
Accretion of planetesimals, age of the solar system, terrestrial planets. Impact craters on the small worlds of the solar system tell us that planets, moons, even larger asteroids were formed by accretion of planetesimals. Larger worlds either have a liquid surface or are geologically active enough to erase most of their craters. The process of formation of the earth also has not ended. 12,000 tons of additional mass from the chelyabinsk meteorite event, the biggest such event that has been seen in more than a century. A planetesimals about 65 feet in size falls through the air at high speed. As it falls, friction with the air heats the object and it mostly explodes before reaching the ground. Observation: the sun as the dominant object. Observation: the confinement of the system mostly to a single plane. Observation: the orderly motions of the planets and their moons. Observation: the segregation of planet types, different kinds of planetesimals and their locations.
