AS101 Study Guide - Midterm Guide: March Equinox, Equinox, Celestial Pole
Document Summary
E d w i n a c h e u n g | 1. Everything we can possibly see if a tiny fraction. We only really know what atoms are (the 5%), we don"t even know what dark matter/energy is, Dark matter = means not visible it"s invisible. Massive ball of glowing gas that generates energy through nuclear fusion. About 100x as wide as the earth. The thing that"s holding the sun together is gravity. Planets are less massive than stars (their difference) Planets are either rocky or gaseous (earth is a rocky planet) How are planets different from stars: planets are less massive, non-luminous (don"t glow on their own) and spherical. Can only see the planets and moon from reflected light. In orbit around a star (need to be in orbit: cleared the neighbourhood of other objects. All of the little objects go away, disappear. Why pluto is not a planet anymore, hasn"t cleared the neighbourhood.
