AST101H1 Lecture Notes - Lecture 18: Oort Cloud, Kuiper Belt, Orion Nebula
23
AST101H1 Full Course Notes
Verified Note
23 documents
Document Summary
The planets orbit the sun in the same direction prograde. The sun and most planets rotate in the same direction (ccw) (except for uranus and venus) Most of the massive moons of the planets orbit their planets in this same direction. There are isoleated dense molecular clouds of fas and dust. Most favmous one is the orion nebula. Force of gravity pulls a molecular cloud (of gas and dust) together. The initial cloud will be slowly rotating in some random direction. Conservation of angular momentum speeds up the cloud"s rotation as it collapses. Rotation ensures not all material collapses to the centre. Even though overall cloud is spinning, individual particles can be moving in random directions. Collissions between particles tend to cancel out up, down, and elliptical motions. Cloud gradually collapses into a spinning pancake shaped disk. Tiny small objects stick together to form planetesimals. These are tehs eeds (cores) of what will become planets.
