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About this app

Kepler, by Walter W. Bryant

“I’m sure you remember that Tycho Brahe had his own system of the universe. In a tychonic system, the earth was stationary at the center, the sun went around the earth, and all of the other planets went around the sun. Of course, Tycho believed passionately in his own system, and on his death bed he begged Johannes Kepler to use the new observations to prove the correctness of the tychonic system. It was a touching moment. I have no idea of what Kepler thought of that moment. But the idea of doing what Tycho had asked him to do never even crossed his mind. Kepler was a Copernican to his very core, and as soon as he got his hands on Tycho's data, the first thing that he set out to do was to analyze the orbit of mars. It proved to be enormously difficult, and no matter what he did, he couldn't make the orbit of mars fit a circle. The disagreement between the angular position of mars in the sky and the best circular orbit was eight minutes of arc. In other words, if he had tried to do the same thing before Tycho’s observations, it would’ve been possible. But with the new data, it could no longer be made to work. And so Kepler was faced with a direct conflict between the ancient platonic dictum, that all motions in the heavens had to be circular motions, and the new tychonic observations. Faced with that conflict, he made his choice; he chose the observations. And he started the search for a different smooth curve that would describe the orbit of mars. After years of agonizing work, he hit upon the answer. It was a curve that had been known for thousands of years; and it’s called: an ellipse.” - Dr. David L. Goodstein

“Focus is the Latin word for fireplace. It was first used for the ellipse by a man who became known as the wandering mathematician. His name was Johannes Kepler; and in the sun he saw the greatest fireplace in the universe. In his emotional life, however, particularly as a child, he saw very little in the way of warmth. Kepler’s father, a low rank soldier of fortune, deserted the family early. His mother was later tried for witchcraft. Although, it’s not known whether Kepler senior fled because she had the makings of a real witch. In his father’s absence, Johannes was constantly visited by poverty; and despite his mother’s alleged charms, by illness as well. His background challenges many contemporary notions about heredity and the environment. Though he displayed the skill and curiosity of mathematical genius, Johannes Kepler seemed an unlikely candidate to solve some fundamental problems of the universe.”

“At the dawn of a new century, January 1st, 1600, Kepler set off in search of the most accurate astronomical data on earth, and the man who possessed them: Tycho Brahe… no one on earth appreciated the potential value of Tycho’s heavenly observations better than Johannes Kepler. To him, the data were essential. The key to unlock the door to the universe and to reveal what he called ‘the secrets of the skies’. But much to Kepler’s dismay, Tycho knew how to keep a secret. So, Kepler struggled without Tycho’s precious data for almost two years. Then, on October 24, 1601, fate stepped in. Tycho’s dying words were: ‘Let me not seem to have lived in vain.’ The Dane’s family withheld the data, but Kepler managed to make Tycho’s last wish come true. Advancing science more than ethics, he stole the material. The otherwise mild-manner little mathematician was finally ready, in his own words, to ‘wage my war on Mars’.” - The Mechanical Universe… and Beyond, Lesson 21, Kepler’s Three Laws

Navigation Instructions:

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Use the menu button to select a specific chapter from the table of contents.

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Updated on
Jun 4, 2011

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