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Unformatted text preview: 1 final exam Monday we will discuss the Big Bang Wednesday we will finish the Big Bang and review for the final exam Galaxies 2: Mostly Other Galaxies Todays Lecture: purpose & goals AST 1002 Planets, Stars and Galaxies Hubb l e Deep F i e l d North s ome of the mo s t d i s tant ga l ax i e s L ook i ng at an empty pat c h of s ky 1) Types of Galaxies 2) Galaxy Clusters and galaxy collisions 3) Dark Matter puzzle 4) The Expanding Universe Review: The Milky Way in Visible Light called v i a l a c t i a (latin) or ga l ax i a s kuk l o s (greek) Milky Way Almost everything we see with the naked eye is our galaxy Most individual visible stars seen with the naked eye are foreground stars within a few hundred light years of us. Andromeda Galaxy The exceptions: 2 Milky Way: Structure Disk Near the Sun low density of stars ( 1 star per 330 330 l.y. 3 ) Younger Population I stars, including Blue giants Lost of gas and dust Bulge galactic nucleus high density off stars ( 10 10 million million stars per l.y. 3 ) Older (10 billion year old) Population II stars, mostly red dwarves Halo The globular clusters and many individual widely separated older Population II stars Messier Objects 1784 Charles Messier (French astronomer) he was a comet hunter Identified 103 objects in the sky which were not stars ( 109 in list now). these were fuzzy objects when viewed in small telescopes. wanted to separate the stationary dim fuzzys from comets he was searching for. actually galaxies , globular and open clusters , and nebulae . far away: appears dim and fuzzy. Now a very useful list of interesting and beautiful objects for amateur astronomers to look at. M80 g l obu l ar c l u s ter M16 Eag l e Nebu l a em i ss i on nebu l a w / embedded open c l u s ter M27 Ring nebula p l anetary nebu l a M20 Tr i f i d Nebu l a em i ss i on nebu l a M1 Crab Nebu l a s upernova remnant Looking at Distant Objects...
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