star groups 30.3
DESCRIPTION
Star Groups 30.3. Constellations. Groups of stars that form a pattern in the sky 88 recognized by astronomers to divide the sky into sectors Appear to shift to the west a little each night due to revolution of earth so each season has a different set of constellations. Leo and Orion. - PowerPoint PPT PresentationTRANSCRIPT
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Constellations• Groups of stars that form a pattern in
the sky• 88 recognized by astronomers to
divide the sky into sectors• Appear to shift to the west a little
each night due to revolution of earth so each season has a different set of constellations
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Leo and Orion
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…it’s not actually a constellation….
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…it’s an asterism.
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Galaxies• Large groups
of stars bound by gravitational attraction
• May be a trillion galaxies!
• Avg. 100 LY wide with 100 billion stars per galaxy
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Types of Galaxies Spiral
Elliptical
Irregular
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Hubble Galaxy Classification
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Our Galaxy - The Milky Way• Cloudlike band across the sky
• Spiral Galaxy- we are in one of the armsThe sun takes 200 million years to revolve
around the center
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Star Clusters
• Galaxies also contain groups of stars• They can be open clusters or globular
clusters
Globular Cluster - M80
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Binary Stars
• Most stars in the galaxy are binary or multiple star systems
• They revolve around each other
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