Ancient Astronomers Timeline

By catdog
  • 240 BCE

    Eratosthenes(276-195BC)

    Father of Geography. Greek mathematician, astronomer, and geographer who in 240BC used the sun to measure the Earthś circumference when people believed the world was flat. This discovery was important because it gave people a new view of Earth. He also invented the system of latitude and longitude.
  • 127

    Claudius Ptolemy(90-168AD)

    Greek astronomer and mathematician who in 127 he set up a model for the solar system as a geocentric model that was important for use in astronomy for 1200 years. In the second century, he published Almagest which set up the foundation of Islamic astronomy.
  • 1543

    Nicholas Copernicus(1473-1543)

    Polish astronomer in 1543 published DeRevolutionibus Orbium Coelestium which proposed the heliocentric model of the solar system with the exception of Mars. This was important as it challenged the geocentric model in use up until then.
  • 1572

    Tycho Brahe(1546-1601)

    Danish astronomer and astrologer who in 1572 discovered a new star supernova. This was important in proving that the universe was not unchanging. He also contributed detailed measurements of the path of planets.

  • Johannes Kepler(1571-1630)

    German astronomer who in 1609 published Astonomia Nova which laid the foundations of Keplerś three laws of planetary motion. He used his study of Mars and Braheś planet research to show that the path of planets was elliptical, not in circles as Copernicus proposed. This was important as it changed the entire view of our solar system.

  • Sir Isaac Newton(1643-1727)

    English astonomer who in 1687 published Principa which was important because it established the basic three laws of gravity for modern physics. He discovered gravity as the motion of forces between oblects.

  • Albert Einstein(1879-1955)

    German physicist who in 1915 established the theory of relativity. He established that the speed of light in a vacuum is constant. He also established that gravity is a bending of space and time by mass and energy. This was important because it gave us E=mc².