Remembering Kepler

Yesterday I was listening to This American Life.  I have not finished listening to the episode because one of the first things Ira Glass said was, “…it involves two scientists, one you have definitely heard of, Galileo, the other you may not know, you may just vaguely recall, he is one of the iconic figures of early astronomy, Johannes Kepler…”

That was all I heard before I paused the show, and ran to find Joey and ask if he thought that a large population of people who were unaware of Kepler’s contributions to astronomy and physics actually exists.  Joey agreed with Ira, that many people might not know Kepler, and even if they recognized his name, they might not recall what he did.  It seems I live in a special, magical world where conversations about Johannes Kepler, Tycho Brahe, Fermat, and other great thinkers are almost as common as conversations about the TV show we are watching (Once Upon a Time), or the YouTube video we are obsessed with (Gangnam Style).

I am deeply saddened by the idea that a person who contributed so much to our understanding of physics and astronomy is not better remembered.  So, at least in my small corner of the internet, I hope to correct the situation.

Here is what I remember of Kepler. Johannes Kepler was a German (although Germany was not yet a unified country) astronomer and mathematician who was born in the latter half of the 16th century.  He was a contemporary with Tycho Brahe and Galileo Galilei.  Kepler was also an astrologer, and he looked for a higher meaning or divine structure to the organization of the solar system.  Kepler developed a model of the solar system based on the Platonic solids.  This work led to a correspondence with Tycho Brahe, and eventually the two men worked together.  Brahe had much more accurate data about the position of the planets, based on his meticulous observations.  Brahe advised Kepler, and with this support and further observations of the orbit of Mars, Kepler devised his first law of planetary motion: The orbits of the planets are ellipses, with the sun at one of the foci (pardon the paraphrase, I am doing this from memory).

Kepler also developed two other planetary laws (you will have to check out the wiki article for the details of these.  They are more math-y, and I cannot recite them from memory).  Kepler’s three laws of planetary motion are still understood to be correct.  Kepler’s laws of planetary motion were later explained and supported by Isaac Newton’s laws of motion and theory of [universal] gravity.

Kepler developed a theory about lunar motion, and was able to measure lunar eclipses.

Kepler also worked with optics.  He was interested in understanding the strange light and shadows surrounding eclipses, and would up studying atmospheric refraction, as well as the optics of the human eye.  Kepler corresponded with Galileo, and set out to describe how the convex and concave lenses worked together to create Galileo’s telescope.  Kepler later created his own variant of the telescope which has higher magnification than Galileo’s.

Well, that is what I remember about Kepler.  Given the premise that many people do not know Kepler, I am guessing I did not learn about him in school.  My thought is that my association with people who are interested in math and physics have exposed me to this information about Kepler.  Tycho Brahe is my favorite astronomer (please tell me other people have favorite astronomers), and I know that I gained some of my knowledge about Kepler through reading about Brahe.  I know no one who knows me is shocked to discover that my memory has held onto random information that drifted through my environment.

What I have written here is based on my recollections.  I have checked my work against the interwebs, and it seems my memory was pretty good, although I missed much of the more nuanced bits of the math involved.  If you are interested in reading more about Johannes Kepler, check out the Wikipedia article about him.