ASTR 101 1st edition Lecture 7 Outline of Last Lecture I. Ancient Greek science,II. Copernican revolutionOutline of Current Lecture I. Key people involved in Copernican revolution,II. Earth-centered modelCurrent Lecture—chapter 3 continuedI. 3 key people involved in Copernican revolution: a. Tycho- there is a supernova named after him.b. Kepler- a student of Tychoc. Galileo- the Earth isn’t stationary but is moving around the Sun just like all the other planets.II. Earth-centered modela. Although Brahe compiled much data, he didn’t detect parallex. He thought the Earth wasn’t moving, but maybe the other planets were. Kelper was able to detect parallex. Kepler knew that the Sun was in one of the focuses, and he realized that the orbits were imperfect circles. He broke the symmetry,b. Keplers 3 laws:i. The orbit of each planet around the Sun is an ellipse with the Sun at one focus. A circle is a special kind of ellipse, with the two foci on the same spot. ii. If the planet is further away from the Sun, it will move slower; closer to the Sun, a planet will move faster. iii. P2 = a3; p=orbital period, a=average distance from the Sun (in AU)(p/1 year) 2 = (a/ 1 AU) 3It takes longer for more distant planets to orbit the Sun. Orbital period is proportional to the size of the orbit, and the speed of motion of the planet will be slower. c. Objections:i. Galileo’s experiment showed that an object in motion stays in motion unless some other force is applied—newton’s first law of motion. Venus orbits the Sun and not the Earth.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ii. Tycho discovered a supernova! And Galileo used a telescope to observe the sky. He found sunspots—it’s imperfect. And he also found that the moon is not