ASTR 380 Chapter Notes - Chapter 3: Laniakea Supercluster, Milky Way, Lunar Eclipse
27 Oct 2018
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Copernican revolution showed that aristotelians were wrong, and earth was not unique (more likely that life exists: modern astronomy starts where newton left off. 3 crucial ideas: universe is vast and old. Implies numerous worlds and enough time for life to arise: elements of life are widespread, same physical laws operate throughout the universe. 3. 2 the structure, scale and history of the universe. Solar system is part of the milky way galaxy (island of millions or billions of stars: second largest in the laniakea supercluster (galaxies and galaxy clusters) Sun, mercury, venus, earth, mars, jupiter, saturn, uranus, neptune. Shape: sphere: determined by aristotle, lunar eclipse = moon falls into earth"s shadow, showed curvature, sailing ships = disappear sooner for those on shore v on a hill, stars = different latitudes see different stars. Size: 6371km radius: determined by eratosthenes, comparing how the sun was perpendicular to syene but in alexandria there was a shadow of 7. 5 degrees (used trig)
