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Johannes Kepler (1571–1630)

Johannes Kepler wrote the world's first science fiction story. Called Somnium, or "The Dream", it describes a young boy's trip to the Moon.

Kepler is less famous than his contemporary, Galileo, but his ideas have been just as important.

Like Galileo, Kepler's life was disrupted by religious persecution. Kepler was forced to leave his first job in Graz because he was a Protestant. Fortunately Kepler found a position in a Prague as an assistant to Tycho Brahe. Eventually, after Kepler succeeded Brahe as Imperial Mathematician, Kepler was forced to leave Prague by the new Catholic Emperor, less tolerant than the previous one. Finally Kepler returned to Linz, near his home town but was forced to move once again by the Thirty-Year War.

The first of these moves was the most significant. Brahe was the greatest astronomer of the time. Kepler's relationship with Brahe was quite stormy, but Brahe died within two years of Kepler's arrival.

Kepler succeeded Brahe in his post and retained full access to his observations. Using this data, Kepler worked out the laws of planetary motion, still known as Kepler's laws. Kepler's laws, in turn, led Isaac Newton to his theory of gravity.

For a while, Kepler believed that the spacing between the planets was governed by the sizes of the five Platonic solids—a mysterious connection between mathematics and the Universe.

Because of his mystical inclination, Kepler was not always taken seriously by his contemporaries. Kepler believed that the Universe was ordered according to a divine plan that could be decoded by careful analysis. Despite this—or perhaps because of it—Kepler demanded that his theories match observation to a degree that had never before been required.

Johannes Kepler
magnifyJohannes Kepler

A 19th Century astronomical chart
magnifyA 19th Century astronomical chart

Diagram from Kepler's Mysterium Cosmographicum, 1596
magnifyDiagram from Kepler's Mysterium Cosmographicum, 1596
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