Johannes Kepler

Johannes Kepler was a German astronomer and mathematician. He was born in 1571 in what is now Germany. He discovered the laws of planetary motion. He showed that planets move in oval shapes, not perfect circles.

Early Life

Kepler was born into a poor family. He was a sickly child with poor eyesight. But he was very smart and earned a scholarship to study at university. He became interested in astronomy after watching a comet as a child.

A NASA sky map showing the vast universe Kepler loved to study.
A NASA sky map showing the vast universe Kepler loved to study. (NASA / WMAP Science Team / Wikimedia Commons)

Big Discoveries

Kepler used data from astronomer Tycho Brahe to figure out how planets move. He discovered three laws of planetary motion. He showed planets move faster when they are closer to the Sun. His work helped Isaac Newton develop the law of gravity.

Fun Facts

  • Kepler's mother was put on trial for being a witch, and he helped defend her.
  • He wrote one of the first science fiction stories about a trip to the Moon.
  • Kepler also figured out how eyeglasses work.

Did You Know?

NASA named a space telescope after Kepler. The Kepler Space Telescope discovered thousands of planets around other stars before it was retired in 2018.