NATS 1740 Chapter Notes - Chapter 19: Spiral Galaxy, Cosmic Ray

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Tatiana Paulin

Document Summary

Spiral galaxy- looks like a flat white disk with yellow bulges at the centre. Filled with cool gas and dust and has spiral arms. Disk- portion of a spiral galaxy that looks like a disk and contains cool dust and gas. Bulge- central portion of a spiral galaxy that bulges above and below the galactic disk. Halo- spherical region that surrounds the disk. Star-gas-star cycle- process of galactic recycling in which stars expel gas into space where it mixes with interstellar medium to form new stars. Bubble- an expanding shell of hot gas driven by supernova or stellar winds. Cosmic rays- particles like protons and electrons that zip through space at almost the speed of light. Disk population- stars that follow orderly orbital patterns. Young and old starts with 2% heavy elements. Halo population- stars orbit the center of the galaxy with different inclinations causing them to cross through the disk as they orbit.