ASTR 001 Lecture Notes - Lecture 2: Cosmological Principle, Old Ideas, Physical Law
15 Jul 2020
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Document Summary
Our view from the earth is not special or unique. Distant objects should be like nearby ones, which we can study in detail. Matter and energy obey the same physical laws everywhere. We can learn about distant objects by studying nearby ones. Most scientific fields work by conducting controlled experiments. Astronomy is an observational science in which mathematical and physical models based on established theory are used to explain observations or predict what new observations should reveal. Example: einstein predicted that light would be bent by gravity of the sun in his general theory of relativity. A few years after this prediction, observers measured the predicted amount of bending during a solar eclipse. Must be able to think of new ideas and new solutions to new and old problems. Old ideas can be falsified and rejected. New ideas must be supported by evidence. There can be major overhauls and revolutions.
