Scientist of the day -Johannes Kepler

Johannes Kepler  (1571 - 1630)

Johannes Kepler was a key player in a profound change in the tide of human thought: the scientific revolution. In Kepler’s lifetime:

Kepler reflected the times he lived in. Seen through modern eyes, he had somewhat contradictory ideas. He was:

Such contradictions were not unusual during the scientific revolution. Isaac Newton, who lived in a later time than Kepler (1643 to 1727) did not work in the way a modern scientist would. Also a Protestant with unorthodox views, Newton spent more time investigating the true meaning of the Bible’s words and on the pseudoscience of alchemy than he did on mathematics or physics!

Johannes Kepler’s Early Life and Education

Johannes Kepler was born on December 27, 1571, in the town of Weil der Stadt, which then lay in the Holy Roman Empire, and is now in Germany.

When Johannes was about five years old, his father, Heinrich Kepler, was killed in Holland fighting as a mercenary. His mother, Katharina Guldenmann, was a herbalist who helped run an inn owned by her father.

Kepler’s First Law – The Law of Orbits
Kepler tried to figure out the mathematical shape of Mars’s orbit. After about 40 misses, in 1605, he got it right. Mars follows an elliptical path around the sun.

And now he formulated what would become Kepler’s first law: planets orbit the sun in ellipses, with the sun at one focus.

Kepler’s Third Law – The Law of Periods
Kepler never gave up his idea that regular polygons determine the orbits of the planets. As a fortunate result of this wrong thinking, he continued calculating and theorizing.

In 1618 his continuing research led to his third law of planetary motion:

The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit.

Restated crudely, this law means that if we square the time it takes a planet to complete one orbit around the sun, we’ll find it’s proportional to the planet’s distance from the sun cubed.

Even more crudely: the farther a planet is from the sun, the slower it moves along its orbital path.

The End

Johannes Kepler died after falling ill at the age of 58, on November 15, 1630 in the German city of Regensburg. He was survived by a son and a daughter from his first marriage, to Barbara Müller, who died rather young. He was also survived by his second wife, Susanna Reuttinger, and two sons and a daughter from that marriage.