Lecture 22 - Lecture 22 11/23/10 There are two ways to...

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Lecture 22 – 11/23/10 There are two ways to measure mass: a) F = ma so m = F/a Gravity bends light so you can see things that otherwise would be hidden from your line of sight Our galaxy a) Spiral galaxy b) Has spherical halo which means low number of stars c) Concentration of stars in the center d) Sun is not at the center- dust and gas obscure high density of stars in the center Galaxies a) Collection of billions of stars b) Size is about 100,000 light years across c) Come in different shapes and sizes d) Tend to form in clusters Globular clusters a) Concentrated around the galaxy b) Shapley realized these clusters and discovered a period-luminosity relationship Star clusters a) Open clusters are found within the galactic disk Stellar orbits a) Stars in galactic plane have circular orbits while those in the halo have crazy orbits Galaxy rotation a) Not rigid objects b) Differential rotation- objects closer in move fast while those farther out move slow
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This note was uploaded on 05/03/2011 for the course AST 301 taught by Professor Harvey during the Fall '07 term at University of Texas at Austin.

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Lecture 22 - Lecture 22 11/23/10 There are two ways to...

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