AST101H1 Lecture Notes - Planets In Astrology, Gas Giant, Ice Giant

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Michael Reid

Document Summary

Stars are balls of plasma (a charged gas), which produce energy by nuclear fusion. Stars are producing a lot of excess energy via nuclear reactions. Planets are not producing a lot of extra energy. Planets are rocky, icy, or gassy, and they do not produce much energy. Terrestrial earth like planet (mars), prototypical gas giant planets (saturn), ice giant (neptune). Definition of planet: 1: planets orbit stars directly (not other planets) 2: planets must be massive enough for their own gravity to compress them into spherical shapes. That is, there cannot be a lot of other stuff orbiting the parent star in orbits very similar to the planet. Pluto is not a planet because its orbit is full of other object (mainly comets). There are five established dwarf planets: pluto, ceres, makemake, haumea, and eris. Moon is any large body, which orbits a planet. Moon"s are not be definition smaller than planets technically.