Astronomy — Spring 2011

Today students completed the notes on Kepler’s Laws of Planetary Motion. Here is Carl Sagan’s explanation of Kepler’s Laws. The Earth’s orbit has an eccentricity of 0.02. What does this mean to you? Halley’s Comet has e = 0.967. What does this mean to you? Click on the image below for a neat interactive ellipse activity. Try looking at Halley”s Comet. Set e to 0.90 (can’t set it higher) and semi-major axis for 18 AU. Zoom out to see how it “falls” towards the sun.

Students draw three ellipses using a string and push-pins. They measure the semi-major and semi-minor axes and then the eccentricity (e) of the ellipses. Elliptical Orbits Activity