PHYS 1000 Lecture Notes - Lecture 1: Lunar Eclipse, Celestial Equator, Tropical Year
12 Feb 2018
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Document Summary
Earth is average - we don"t occupy any special place in the universe. Universe: totality of all space, time, matter and energy. The only special thing about us is life, and only b/c we don"t proof of life of anything else. Scales are very large, measured in light-years or the distance light travels in a year - about 10 trillion km. About 3000 stars visible at any one time (6000 if you include both sides of the planets); distributed randomly but the human brain tries to find patterns. This lead to people group stars into constellations (there is 88 constellations). Stars that appear close in the sky may not actually be close in space. The celestial sphere: stars seem to be on the inner surface of a sphere surrounding the earth. They aren"t, but we can use 2d spherical coordinates (similar to latitude and longitude) to locate sky objects.
