NATS 1745 Lecture Notes - Lecture 11: Harlow Shapley, Spiral Galaxy, Hubble Space Telescope
17 Jul 2017
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Document Summary
The island universe theory is the theory that the universe is comprised of numerous galaxies, of which the milky. The ancient greeks used the word galaxy to describe the bright strip of light across the sky because they thought it had a milky appearance and so they named it glaxius" the greek for milky. William herschel and son john herschel used their giant telescopes to catalogue over 5000 nebulae . They attempted to identity whether nebulae are distant star systems or nearby glowing gas clouds. A variable star is a star that fluctuates in brightness at regular time intervals. Cepheid variables are luminous, and they pulsate dramatically & rapidly in intervals of days or weeks. What did henrietta leavitt discover when she observed cepheids in the. Smc - small magellanic clouds lmc - large magellanic clouds- they are near galaxies. She discovered cepheid"s obey the period luminosity relationship.
