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Galaxies live in clusters |
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Rich clusters: thousands of galaxies |
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Poor clusters: Few than a thousand |
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Fundamental difference between stars
and galaxies: |
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Stars live isolated lives: |
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They are much smaller than distance
between them |
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They virtually never collide |
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Galaxies are not isolated |
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They are only slightly smaller than the
distances between them |
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The can (and do) collide, and interact
with gas within clusters |
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Stars pass “through” each other, but
orbits around galaxy disrupted |
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Gas clouds collide |
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Gas stripped away from stars |
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Collisions cause bursts of star
formation |
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Ellipticals may be those galaxies which
have suffered collisions |
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Spirals may be those galaxies which
have not suffered collisions |
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Joshua Barnes (Hawaii) and the Space
Telescope Science Institute provide a simulations of galaxy mergers. Barnes website: |
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http://www.ifa.hawaii.edu/faculty/barnes/transform.html |
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Simulation of the Milky Way and its
future merger with the Andromeda galaxy: http://www.npaci.edu/online/v4.9/galaxies2.html |