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Characteristics Of Stars. Galaxy: A collection of stars, gases and dust. Universe: Contains billions of galaxies. Types of Galaxies. 1. Spiral 2. Elliptical 3. Irregular. Spiral Galaxies:. Arms spiral outward like a pinwheel Our galaxy, The Milky Way, is a spiral galaxy.
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Characteristics Of Stars • Galaxy: A collection of stars, gases and dust. • Universe: Contains billions of galaxies.
Types of Galaxies • 1. Spiral • 2. Elliptical • 3. Irregular
Spiral Galaxies: • Arms spiral outward like a pinwheel • Our galaxy, The Milky Way, is a spiral galaxy
Elliptical Galaxies: • Look like flattened balls or a football. • Have billions of stars, but little gas and dust. • Contain the oldest stars
Irregular Galaxies • No definite shape • Example: Large Magellanic Cloud
( Light will travel 9.5 million, million kilometers in one year!) • Scientists use LIGHT YEARS to measure distances in space. A light year is the distance light travels in one year. • Light travels at the speed of 300,000,000meters/second.
Classifying Stars • Stars are classified by 3 Main Characteristics: • 1. Size • 2. Temperature • 3. Brightness
Color reveals the temperature of a star. • Hottest (20,000-50,000*C) • : (10,000*C) • (6,000*C) • (4,000-5,000*C) • (3000*C) Blue White Yellow Red-Orange Red
Brightness of Stars • Apparent Magnitude: Brightness as seen from earth • Absolute Magnitude: Brightness of a star from a standard distance
Hertzsprung-Russell Diagram • A graph plotting brightness and temperature. • 90% of stars are Main Sequence