ection 2
Johannes Kepler—German astronomer [1571-1630] derived three laws that describe
the motions of the planets around our Sun, the moon around the Earth, or any space-
craft launched into orbit.
Early frail health seemed to destine Kepler for the life of a scholar. He was born into a
dysfunctional, chaotic family and spent his lonely childhood with a variety of illnesses.
He had myopia and multiple vision—unfortunate afflictions for the eyes of an
a s t ro n o m e r.
Kepler intended to dedicate himself to the service of the Protestant church, but his
independence, lack of orthodoxy, and disagreeableness led his university teachers to
recommend him as a mathematics professor to a school some distance away. During
this period, astronomy became an important focus.
Early writings of Kepler’s attracted the attention of Tycho Brahe, the Danish astronomer.
Kepler joined Brahe’s staff in 1601. When Brahe died the following year, Kepler inherit-
ed Brahe’s meticulous astronomical observations—considered critical to Kepler develop-
ing his first two laws of motion. Within days of Brahe’s death, Kepler was appointed
Brahe’s successor as imperial mathematician of the Holy Roman Empire, a position
Kepler held until his death.
Kepler was a transitional figure between ancient and modern science. Astrology often
played an important, and sometimes dominant role in his life.
Kepler’s laws stirred little interest for decades, only Newton seemed to realize their
value. Kepler’s laws describe how planets move. Newton’s law of motion describes why
the planets move according to Kepler’s laws. Kepler himself never numbered these laws
or specially distinguished them from his other discoveries. Kepler’s laws apply not only
to gravitational forces, but also to all other inverse-square law forces.
In the last decade of his life, Kepler wandered in search of a haven or a patron. In the
fall of 1630, Kepler rode across half of Germany to collect pay and arrears due him.
The exertion of the trip was responsible for Kepler’s illness and death in Regensburg on
November 15, 1630. He was buried outside the town walls. Subsequent conquest of
the city decimated the cemetery and left the site of Kepler’s grave unknown.
JO H A N N E S KE P L E R
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