NATS 1880 Lecture Notes - Lecture 2: Net Force, Scientific Method, Pseudoscience
23 Oct 2014
School
Department
Course
Professor
Document Summary
Life beyond earth - september 23, 2014 (chapter 2 continued) Seasons have nothing to do with earth"s distance from the sun. Rather, the tilt of the earth"s axis generates our seasons. The celestial sphere represents where all the planets, stars, etc. reside. The sun moves across that celestial sphere. Seasons arise from axial tilt, not from distance from the sun. Galileo also saw four moons orbiting jupiter proving that not all objects orbit earth. Used this to verify the idea that we live in a heliocentric universe. He noticed that venus exhibited phases very similar to our own moon. He argued that those phases were only visible if the earth and venus were both moving around the sun. Depending on the geometry of where you are on the earth, we see different phases of venus just as we see different parts of the moon during the different phases.
