- Copernicus was a Polish astronomer and clergyman
who, in 1543, introduced a new heliocentric system of the universe.
In Copernicus's system, the planets revolved on a complex system
of epicycles, but they all revolve around the sun. This was a revolutionary
idea in the sixteenth century. Everyone was firmly convinced that
the earth was motionless at the center of the universe. To imagine that
it moved around the sun seemed ridiculous. It took several decades
for the Copernican system to become fully accepted by astronomers
and the public. Kepler was the first major astronomer to publicly
acknowledge his support of it.
Tycho de Brahe
- Tycho de Brahe was a Danish nobleman who made a name
for himself in the late sixteenth century as Europe's best observational
astronomer. He kept a closely guarded collection of astronomical
observations, the most accurate astronomical data available at
the time. Eager to use Tycho's figures to develop his own system,
Kepler traveled to Prague to work in Tycho's lab. In addition to
being a brilliant astronomer, Tycho was also an arrogant and temperamental
man. Tycho and Kepler had a love-hate relationship; they respected
one another, but each was also jealous of the other's achievements
and potential. Several times, Kepler fled the lab, only to return
full of apologies. When Tycho died, he expressed a hope that Kepler
would use his data to develop the Tychonic system of the universe,
in which the planets orbited the sun, which orbited the earth.
Instead, Kepler applied Tycho's observations to the Copernican system,
which led him to discover his first two laws.
- Galileo was an Italian astronomer who discovered
the moons of Jupiter. Galileo was the first major astronomer to
use a telescope to observe the heavens. When these observations
yielded findings that the scientific community was reluctant to
believe, Kepler lent him public support Galileo later became a symbol of
science's break from religion during the scientific revolution.
He was put on trial by the Catholic Church and convicted of heresy
for his support of the Copernican system
- Kepler's father, Heinrich, was an itinerant criminal
who repeatedly abandoned his family. At one point he owned a tavern,
at another, he was nearly hanged for an alleged crime. One of Kepler's
younger brothers was forced to run away from home when Heinrich
threatened to sell him. Heinrich left for good in 1588 – he was
- Katherine Kepler,
Kepler's mother, was born Katherine Guldenmann. She was the daughter
of an innkeeper and the niece of a woman who had been burned at
the stake as a witch. Kepler later described her as a petty, angry, quarrelsome
woman. She came back into Kepler's life in 1615, when her fellow villagers
accused her of being a witch. Kepler was quick to come to her defense. After
five years of argument and negotiation, Katherine was interrogated
under threat of torture. When she continued to deny being a witch,
she was finally released. She was driven from her town and died
six months later.
- Michael Maestlin was Kepler's most influential teacher
at the University of Tuebingen. Maestlin was the first to teach
Kepler about the Copernican system. In the classroom, Maestlin
was a strong supporter of the Copernican system, but on paper,
he continued to propound the Ptolemaic system. Kepler turned to
Maestlin for help and advice throughout his life, but Maestlin
seems to have grown tired of his troublesome student. He often
ignored Kepler's letters for years at a time.
- Kepler married Barbara Muehleck in 1597. It was a
marriage of convenience, not love. Kepler's friends had decided
it was time for him to marry and had chosen Barbara as a good mate;
Kepler acquiesced. They were married for fourteen years and had
four children. Barbara died in 1611 of the Hungarian fever.
- Two years after his first wife died, Kepler married
the 24-year-old Susanna Pettinger. They had eleven children together
and Kepler had nothing negative to say about her in later life
– a ringing endorsement considering the way he described most of
his family members.
an astronomer from the second century A.D., formulated a system
of the universe that lasted for over one thousand years after his
death. His system placed the earth at the center of the universe,
with the planets and the stars revolving around it. Ptolemy insisted
that the planets in his system moved with uniform circular motion.
Because this is not actually how the planets move, he was forced to
introduce the following mathematical devices. The deferent is the
main circle around which each planet orbits the earth. An epicycle
is a smaller circle around which the planet orbits the deferent.
Finally, the equant is an imaginary point in the exact center of
the planetary orbits. Ptolemy's system was so complex that, by the
time of Copernicus, it contained somewhere between forty and eighty epicycles.