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Galaxies Can Be Weird …just like Michael. Hubble Deep Field - 2004. Thumb nail of the sky. HDF – Close Up. Approximately100 Billion Galaxies !!! Northern Hemisphere can see Andromeda – 200 million ly away
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Hubble Deep Field - 2004 • Thumb nail of the sky.
Approximately100 Billion Galaxies !!! • Northern Hemisphere can see Andromeda – 200 million ly away • Southern Hemisphere can see the large and small Magellanic clouds. – approx. 180 kly away
Milky Way Facts • Rotational Speed of roughly 780,000 km/h • We are midway between the Orion and Perseus arms about 26 kly from the center. • The sun rotates once every 230 million years. Near the core only decades to rotate. • Center of the galaxy is Sagittarius A, a 3 million solar mass black hole • 300 + billion stars • 100,000 light years in diameter.
More about structure • O-B associations – open clusters (young hot stars=population 1) define the arms. • Globular Clusters (100’s of thousands of older stars=population 2) inhabit the halo • Galactic center = Population 2 stars and a giant super massive black hole (several million stars) • 350 ly from center is the Great Annihilator. • Why does it “stick” together? Dark Matter Halo?
Problems • Is the Milky Way the universe or not? • Viewing problems • Hubble tackles the problem using luminosities • Looking back in time at quasars
Elliptical GalaxyHot and early star formation = 60%older stars and very little formation
Spiral GalaxySombrero Galaxy NGC 4594Long and slower sustained star formation = 25-30%
Irregular GalaxyGalaxies that are gravitationally deforming each other.
Active Galaxies • Radio, Quasars, Seyferts Image Courtesy of http://www.linnaeus.uu.se/online/phy/macrocosmos/agn.html
Clusters • Poor Clusters – 10’s of galaxies or so • Rich Clusters – 1000’s of galaxies! • Super Clusters! – 10’s of clusters.
Local Group • 10 million light years across • Major players: Milky Way, Triangulum, and Andromeda • Magellanic clouds are nearby • Sagittarius Dwarf Elliptical being torn apart • Merger is our probably destiny. • Andromeda and Milky Way are locked and closing at 1 million k/h. They will meet in 4 billion years
Your Mission… • Create a graphic analogy that compares galactic structures to people. (3/4/5) • Create an layered image displaying a galactic center, O-B associations, dark matter, molecular clouds (HII), and density waves. (4/5) • How are active galaxies like being at a night club? (3/4) • Create a marching band routine route to show Charger fans all the different types of galaxies. (3/4/5) • Create a “kid accessible” visual guide to the galaxies. (4/5)