AST 101 Lecture Notes - Lecture 14: White Dwarf, Interstellar Space, Hydrogen Atom
21 Jul 2016
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Document Summary
A large, glowing ball of gas that generates heat and light through nuclear fusion. A great island of stars in space, all held together by gravity and orbiting a common center. Filaments and voids in galaxy distribution in the universe. The sum total of all matter and energy; that is, everything within and between all galaxies. Dusty gas clouds obscure our view because they absorb visible light. This is the interstellar medium that makes new star systems. Stars in the disk all orbit in the same direction. Stars in the disk all orbit in the same direction with a little up-and-down motion. Sun"s orbital motion (radius and velocity) tells us mass within sun"s orbit: 1 x 1011 msun. The orbital speed (v) and radius (r) of an object on a circular orbit around the galaxy tells us the mass (mr) within that orbit. The outer part of stars go back to interstellar space.
