Johannes Kepler, a 17th-century German astronomer, moved science from superstition toward mathematics. He discovered that planets orbit in ellipses, not circles, and that orbital periods relate to distance from the sun. His mother faced witchcraft accusations; a comet inspired him as a child.
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Hello, I'm Lois Letchford, reading for a series that I have titled Change the World, people who have changed the world, mostly from the book Eureka. Talking Change the World, Johannes Kepler, 1571 to 1630. He's a German astronomer who established the basis for planetary motions. And who also had to defend his mother on a charge of witchcraft. Perhaps more than any other figure, the German astronomer and mathematician Johannes Kepler can be seen straddling the divide between the old dogma and superstitions-ridden way of looking at the universe and the new method of inferring the workings of the world from the evidence of the senses and construction of mathematical models. At first though, as with Copernicus, Kepler was to a greater extent misled by the notions of how the cosmos ought to be. Copernicus thought the circle was a divinely ordained geometrically figure, while Kepler thought the distance of the planets from the Sun should reflect harmonic values. And I'm just going to read sections of this, not all of it. As a child, Kepler saw the Great Comet of 1577, an experience he apparently never forgot. It's probably from this that his lifetime passion for astronomy stemmed. Experience again. Experiences count. So it goes on to say that he graduated from the university and he taught mathematics at the University of Graz in Austria. And I want to go on and say in 1609 Kepler published a massive treatise called Astronomia Novia, A New Astronomy. Embedded within were the first 2 of his 3 laws of planetary motion. Back in the mid-1519s, Kepler had realized that the planetary orbits really didn't match up to his scheme of regular convex polyhedra. Check that out for a name— regular convex polyhedra. At the same time though, neither did they match up with the Copernican system. Which had the planets moving in circles. Kepler's great conceptual breakthroughs based on his calculations of planetary motion was using Tycho's painstaking observation was that planetary paths were ellipses. That was a big move. His first law states then that a planet traces out an ellipsis as it goes around the Sun, which sits at one of the 2 foci of the ellipse. His 2nd law, which he in fact worked out first, states that an imaginary line drawn between the Sun and a planet sweeps out equal areas in equal time. What this means is that the closer the planet gets to the Sun during its orbit, the faster it moves. And his 3rd law had to wait until the publication of his book, The Harmony of the World, 1619. And as you might guess from the title, much of this densely packed, nightly— nigh unreadable text harked back to the preconception of the ancients that music was integral to the working of the universe. So this is Kepler and his work. Check him out. And it says he was not just an astronomer. We tend to think about Kepler's feats in astronomy, but there were other areas of science in which he made significant contributions. And that's what we need to know, that these people were thinking all the time, and that's what we want our students to do. Uh, so the last paragraph is Kepler remains a giant in the history of science, his reputation, if anything, increasing as time goes on. And yet his burial place is unknown, the graveyard in Regensburg where he was laid to rest having been completely destroyed by one or another faction during the Thirty Years' War. So thank you. Hit like, hit subscribe, share it, and follow this series of Who Else Changed the World?
