Astronomy 1021 Lecture Notes - Lecture 2: Cosmic Microwave Background, Radiometric Dating, Snow Globe
22 Sep 2016
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Document Summary
The universe must be at least as old as its oldest constituents. Look at the ratio of different atoms and molecules. We use all of these different methods and put them together to determine information. Imagine earth is in a snow globe. From our perspective on the ground the stars appear to be on this imaginary surface. Fixed with respect to the observer not the stars. Also known as the alt az coordinate system. The point directly above your head is the zenith . On the opposite (what you cannot see) is the nadir . Both side are the horizon (north point, and south point) Local meridian: the line that goes from the north point on the horizon, through the zenith, to the south point on the horizon. Altitude: the angle between the observer"s local horizon and the point of interest. Azimuth: the angle around the horizon to a point of interest. This system is relative to the earth.
