PH 104H Lecture Notes - Tidal Locking, Orbital Speed, Gravitational Energy
5 Mar 2013
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Star: huge ball of gas held together by gravity. 100x wider than the earth, 1,000,000x larger, 300,000x as massive. 1 au = average distance between the earth and sun. 150 million km 93 million miles. The earth: astronomy study of the universe, planet earth size defined the fundamental unit of the metric system: the meter, moon = earth"s satellite. 1/25 the size of earth: surface = craters, less internal heat than earth, no atmosphere not protected from impacting objects, no erosion or geological activity = no surface change ever. Planets: mercury venus earth mars jupiter saturn uranus . Ear: white clouds, blue oceans, green jungles, red deserts: mar: canyons, deserts. Look-back time; it s how far back in time we are seeing. Distance to an object whose parallax motion measures 1 sec of arc in 6 months of observation time on earth. Parallax - apparent shift in position of some object because of change in position of observer.
