Lecture #14 -- The Finer Points of Orbits


I. Gravity topics
-- gaps in rings due to resonances with large moons and shepherding
-- Lagrange points and trojan asteroids
-- "horseshoe" orbits
II. Forces on dust and small rocks in solar system
-- solar wind causes very small particles to blow outward
-- radiation pressure on particles with size < 1 micron blow outward
-- Poynting-Robertson effect makes roughly 1 cm particles spiral inward
-- Yarkovsky effect for particles of size about 10 m go inward or outward, depending if they rotate opposite or in the same direction as they orbit
-- normal gravity and Kepler's laws apply to anything bigger
III. Interplanetary travel -- escape speed from Earth -- launch near equator -- spacecraft in orbit around the Sun -- trajectory to outer planets -- trajectory to inner planets -- "slingshot" effect -- using planets to get a speed boost