PHYS 1201 Lecture Notes - Lecture 1: Planetary Nebula
Document Summary
Nuclear fusion: requires extremely high temperatures. Gravitational equilibrium - natural balance between two competing forces: gravity pulling inward & pressure pushing out, pressure makes the gas hot enough to sustain nuclear, energy from fusion heats gas & maintains balance of sun fusion. Born about 4 billion years ago from a collapsing cloud of interstellar gas. Born with enough hydrogen in its core to shine steadily & maintain gravitation equilibrium for about 10 billion years. Sunspots dark splotches on the sun"s surface. Entire sun does not rotate at the same rate. Solar equator completes one rotation in about 25 days & rotation period increases with latitude. Power the rate at which energy is used or released. Solar wind stream of charged particles continually blown outward in all directions from the sun. Surface seethes & churns like boiling water. Temperature rises = fusion increases = core expands & cools. Temperature drops = fusion decreases = core shrinks & heats.
