Johannes Kepler was born in Weil der Stadt in Swabia,
in southwest Germany. He moved to nearby Leonberg with
his parents in 1576. His father was a mercenary soldier who
is believed to have died in the war in the Netherlands.His
mother was the daughter of an innkeeper; both of his
grandfathers were mayors. Kepler started his education at a
local school and then attended a nearby seminary. From
there, he went on to enroll at the University of Tubingen.
There he was taught by one of the leading astronomers Michael
Maestlin. He introduced him to the new, heliocentric
cosmological system of Copernicus. The curriculum was geoentric
astronomy: the theory in which all seven planets (Moon,
Mercury, Venus, Sun, Mars, Jupiter, and Saturn) moved around
the Earth. However, Kepler did not like this very much. In his
earliest published work, Mysterium Cosmographicum (1596), he
considered the actual paths of the planets, not the circles used
to construct them. In Kepler's writings, he tended to lay his
opinions on the line. This tendency to openness led the authorities
at Tubingen to doubt his religious orthodoxy. This may explain
why Maestiln persuaded Kepler to give up his plan for ordination
and, instead, teach mathematics at Graz. Kepler was
excommunicated in 1612 and never succeeded in getting the ban
lifted.
Marriage and Death:
Kepler married twice throughout his lifetime. The first seemed to be
for love, however, his wife Barbara died in 1612.They had three
children; only one Ludwig lived for longer than seven years.The
second, however, was out of necessity; he needed a wife to watch
over the children. Her name was Susanna Reuttinger, and they had
seven children but 3 died at a young age. Kepler eventually died in
Regensburg, after a short illness. He was buried in the local church,
but the tomb was destroyed during the Thirty Years' War and
nothing remains.
Kepler's Writings:
The Harmony of the World, planned in 1599 as a development
of his Mystery of the Cosmos, contains Kepler's Third Law. The
mathematics in this work contains the first sustematic proof that
there is only thirteen convex uniform polyhera (the Archimedean
solids. Two non-convex regular polyhedra are also first accounted
in this writing. IIn 1604 Astronomia pars Optica ("The Optical Part
of Astronomy") appeared, in which he treated atmospheic refraction
but also treated lenses and gave the modern explanation of the
workings of the eye. His first two laws appear in his book
Astronomia Nova ("New Astronomy"), finished in 1609. Another
writing by Kepler De Vero Anno quo Aeternus Dei Filius
Humanam Naturam in Utero Benedictae Virginis Mariae
Assumpsit (Concerning the True Year in which the Son of
God assumed a Human Nature in the Uterus of the Blessed Virgin
Mary") stated Kepler's idea that the Christian calender was in error
by 5 years. He stated that Jesus was actually born in 4 b.c., a
conclusion that is now universally accepted. He also published
other writings including Epitome Astronomiae Copernicanae
("Epitome of Copernican Astronomy") which eventually became
known as the most influential intorduction to heliocentric astronomy.
Before Kepler:
<Ptolemy
The discovery of retrograde motion in the orbit of mars
was a serious challenge to the standard geocentric cosmology.
Ptolemy created a theory of all the planets orbitting around the
earth in the same directoin, with the earth being the center of the
universe.
As a child, Kepler helped at
his grandparents' inn by
serving customers.
Kepler married his second
wife only to have someone
to look after his children.
Kepler's Laws:
1. The paths of the planets are
ellipses with the center of the
sun at one focus. View
Kepler's
First
Law!
2. An imaginary line from the
sun to a planet sweeps out
equal areas in equal time
intervals. Thus, planets move
faster when closest to the sun
and slowest when farthest
the sun. View
Kepler's Second
Law!
3. The ratios of the squares of
the periods of any two planets
revolving about the sun is
equal to the ratio of the cubes
of their average distances from
^Kepler's First Law^
^Kepler's Second Law^
^Kepler's Third Law^