Astronomer Biography Johannes Kepler

About the astronomer Johannes Kepler, history and biography of the man who established Kepler's Laws.



(1571-1630, Germany)

Major Discoveries: Kepler's three laws established that the earth is but a minor planet rather than the center of the universe, and that all of the planets travel around the sun in mathematically predictable elliptical orbits.

Means of Observation: Afflicted with poor eyesight resulting from a childhood disease, Kepler was able to make no direct observations himself. But he inherited some 20 years' worth of detailed and precise observations made by the Danish astronomer Tycho Brahe. Kepler applied his considerable mathematical skill to deciphering the pattern in the data, laboriously testing more than 70 models of the universe before finding one that was totally consistent with Brahe's measurements.

His Story: More astrologer than astronomer, Kepler was intrigued by the Pythagorean idea of a universe governed by mystical numerical and geometrical patterns. In 1606, the same year that he developed his first two astronomical laws, he boldly interpreted the disappearance of a certain very bright star as signaling the approaching destruction of the Ottoman Empire. (The empire didn't actually collapse until after W.W.I.) At the same time, he correctly predicted that on May 29, 1607, the planet Mercury would pass in front of the sun. He always considered one of his greatest works a theory that the five regular geometrical solids (the tetrahedron, cube, octahedron, dodecahedron, and icosahedron) formed the basis of the spacing between the six planets known in his day. In addition to casting horoscopes, publishing meteorological almanacs, and analyzing Tycho Brahe's astronomical data, he found time to do the first definitive study on the function and dysfunctions of the human eye, to publish a treatise on the capacity of wine vessels, and to marry--twice. His last work was a science fiction book titled Somnium ("Dream"), in which the footnotes are much longer than the story.

The premature offspring of a grossly mismatched German couple, Kepler suffered an unidentified illness at age four that left him with a crippled hand, poor vision, a constantly running nose, and a generally delicate constitution. His mother was a quarrelsome and unattractive woman with leanings toward the occult--traits that would later lead to her prosecution as a witch. His father, a mercenary soldier taken to long absences from home, managed to sire five more offspring before disappearing completely, to nobody's great regret.

Young Kepler was granted a scholarship to prepare for the Lutheran ministry, but he soon abandoned this in favor of the study of astronomy at the University of Tubingen. There he first encountered the Copernican model of the sun-centered universe--a theory that the Church was desperately trying to keep secret. Although Kepler's early publications probably set science back several years, the astronomer Tycho Brahe was impressed enough with his mathematical abilities to invite him to join him in Denmark. Tycho had an idea for a "Tychonian" model of an Earth-centered universe and hoped that Kepler could prove its truth by analyzing Tycho's observational data. The two men immediately had a series of personality clashes, which ended when Tycho Brahe unexpectedly died. Kepler thereupon abandoned the Tychonian model but kept the data records. Yet Kepler paid a lasting tribute to the Dane, whose observations predated the invention of the telescope by several decades. Analyzing the orbit of Mars for the 70th time, Kepler found a discrepancy of just eight minutes of arc between the actual data and the circular orbit requirement of the Copernican model. Rejecting the possibility that Tycho could have mismeasured by even this small amount, he remarked, "Upon this eight minutes I will yet build a theory of the universe!" And he did.

Financial problems plagued Kepler throughout his life. One aristocrat-sponsor after another proved to be unreliable, and Tycho Brahe's heirs were most troublesome. En route to collect on some promissory notes on Nov. 15, 1630, he collapsed in the town of Regensburg and died. The upheavals of the Thirty Years' War later obliterated his grave.

You Are Here: Trivia-Library Home » Biography of Early Astronomy and Astronomers » Astronomer Biography Johannes Kepler
« Astronomer Biography GalileoAstronomer Biography Isaac Newton »
DISCLAIMER: PLEASE READ - By printing, downloading, or using you agree to our full terms. Review the full terms at the following URL: /disclaimer.htm