Betelgeuse Rigel The Fingerprints of Elements Emission Spectral
Betelgeuse Rigel
The Fingerprints of Elements Emission Spectral Lines Hydrogen Helium Neon Sodium Mercury
What is a Galaxy? It is a group of billions and billions of stars held together by gravity.
Spiral Galaxy Bulge Disk Top View • Huge; contains stars, gas, and dust • Held together by gravity • Pinwheel shape/looks like a hurricane • Bulge and thin disk • Halo (glow) is present • Rich in gas and dust • Young and old stars are present Side View
Spiral Galaxy
Spiral Galaxy
Spiral Galaxy
Spiral Galaxy
Elliptical Galaxy • Huge; contains stars, gas, and dust • Held together by gravity • Round to oval • Bulge but no disk • Halo is present • Little cool gas and dust • Mainly OLD STARS are present
Elliptical Galaxy
Elliptical Galaxy
Elliptical Galaxy
Elliptical Galaxy
Irregular Galaxy • Huge; contains stars, gas, and dust • Held together by gravity • No regular shape • May show signs of a disk and/or bulge • Halo is present • Usually rich in gas and dust • Young and old stars are present
Irregular Galaxy
Irregular Galaxy
Irregular Galaxy
Nebulae Planetary Nebula (death of a star) Movie Stellar Nebula (where stars are born)
Stellar Nebula
Stellar Nebula
Stellar Nebula
Stellar Nebula
Planetary Nebula
Planetary Nebula
Planetary Nebula
Planetary Nebula
Colliding Galaxies
Betelgeuse Rigel Orion Constellation
Supernovae
Top View Side View Spiral Galaxy Elliptical Galaxy Irregular Galaxy Huge: contain stars, gas, and dust Huge; contain stars, gas, and dust Held together by gravity Pinwheel shape Round to oval in shape No regular shape Bulge and thin disk; halo is Bulge but no disk; halo is present May show signs of a disk and/or bulge; halo is present Rich in gas and dust Little cool gas and dust Usually rich in gas and dust Young and old stars are present Mainly old stars are present Young and old stars are present
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