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Astronomer · 1571 CE – 1630 CE

Johannes Kepler

History of AstronomyThe Scientific Revolution

Biography

Johannes Kepler was a German mathematician and astronomer who served as Tycho Brahe's assistant and successor. Using Tycho's superb observations of Mars, he discovered that planets travel in ellipses with the Sun at one focus, sweeping out equal areas in equal times — laws that turned Copernican astronomy into precise, predictive science.

Scientific contributions

  • Discovered the three laws of planetary motion
  • Showed that planets move in ellipses, not circles
  • Compiled the Rudolphine Tables from Tycho's data

Major publications

Theories developed

Catalogues

Knowledge connections

Sources & references

The primary and reference sources this topic draws on.

  • BritannicaEncyclopaedia Britannica

    General reference for the history of astronomy, biographies, and cultural context.

  • IAUInternational Astronomical Union

    Official naming, definitions, constellation boundaries, and astronomical nomenclature.