Ancient Astronomers

  • 240 BCE

    Eratosthenes

    Made the first accurate measurement of the Earth's circumference.
  • 150 BCE

    Claudius Ptolemy

    Wrote a book of astronomical observations.
  • 1543

    Nicolaus Copernicus

    Proposed that the Earth and other planets revolve around the sun, or the Heliocentric theory of the universe.
  • 1572

    Tycho Brahe

    Discovered one of the few recorded supernovas in the milky way galaxy.
  • Johannes Kepler

    Discovered the three major laws of planetary motion.
  • Sir Isaac Newton

    Predicted the shape of the Earth.
  • Albert Einstein

    Observation of a solar eclipse confirmed Einstein's prediction that light is bent in the presence of mass.