Contributions To Science Tycho Brahe & Johannes Kepler

And his contributions to science… Tycho Brahe And his contributions to science…

A little about Tycho Born on December 14, 1546 in what is now Sweden. He attended the universities of Copenhagen, Leipzig, Wittenberg, Rostock, and Basel. During this time his interest in astronomy really started to grow.

Tycho’s Nose A part of the bridge of his nose was cut off in a duel at University of Rostock in 1566. He had a metal piece attached to where the part was missing as a replacement.

Observations Brahe observed the new star Cassiopeia in 1572 He proved that comets are not objects in the atmosphere. Made a extremely accurate star catalogue containing 1000 stars. Spent most of his life working on his astronomical tables (before the telescope was invented)

Some of the tools he used…

Tycho’s World System Tycho believed that the Earth was in the center of the world. The sun and the moon circulated around it. The rest of the planets circulated around the sun. This is based mostly on measurements from mars.

The Sun Earth

And his contributions to science… Johannes Kepler And his contributions to science…

A little about Johannes Johannes was born December 27, 1571 in Germany Went to University Of Tübingen Tycho Brahe’s assistant. Used Tycho’s tables to prove the laws of planetary motion

Kepler’s 1st Law of Planetary Motion (Elliptical orbits) The orbits of the planets are ellipses, with the Sun at one focus of the ellipse.

Elliptical Orbits All ellipses have 2 foci A planet’s distance from the sun will change throughout its orbit beacause the sun is at one focus of the ellipse. Aphelion- point farthest from the sun Perihelion- point nearest to the sun At first you can not tell that a planets orbit is not a circle. Pluto and Mercury are exceptions Watch these orbits a

Kepler’s 2nd Law of Planetary Motion (Equal Area Law) The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse.

2nd Law (continued) This means that the speed at which a planet travels around the sun is not constant. Planets travel more rapidly when they are closer to the sun (could not explain why)

Kepler’s 3rd Law (harmonic law) The ratio of the squares of the revolutionary periods for two planets is equal to the ratio of the cubes of their semimajor axes To practice Kepler’s 3rd law click here

3rd Law (continued) The time it takes a planet to travel one orbit around the sun is its period. This law states that the Period of a planet squared equals the cube of its distance: P2=D3 Period must be in Earth years and distance from the sun in astronomical units So the farther a planet is away from the sun, the longer its period of revolution is.

Interactive Websites Orbits Kepler's Third Law Johannes Kepler Tyhco Brahe Tycho Brahe

Bibliography Works Cited Abbott, David, ed. "Tycho Brahe & Johannes Kepler." The Biographical Dictionary of Scientists. Astronomers ed. 4 vols. New York: Peter Bedrick Books, 1984. "Johannes Kepler: the Laws of Planetary Motion." 16 May 2006 <http://csep10.phys.utk.edu/astr161/lect/history/kepler.html>. Koch, David, and Alan Gould, comps. "Johannes Kepler: His Life, His Laws and Times." NASA. 28 July 2005. 15 May 2006 <http://kepler.nasa.gov/johannes/>. Spaulding, Nancy E., and Samuel N. Namowitz. Earth Science. Ed. Ceanne Tzimopoulos. Evanston, Illinois: McDougal Littell, 1994. 405-406. "Tycho Brahe, Danish Astromer 14/12 1546 - 24/10 1601." Tycho Brahe Homepage. 9 Sept. 2002. 12 May 2006 <http://www.nada.kth.se/~fred/tycho/index.html>. "Tycho Brahe." The Galileo Project. 1995. 10 May 2006 <http://galileo.rice.edu/sci/brahe.html>.