Ancient Astronomers

By 19agordon
  • 276 BCE

    Eratosthenes (276 BC - 194 BC)

    240 BC- Eratosthenes calculated the circumference of the Earth.
    255 BC- He invented the armillary sphere
    Because of his calculated circumference of the Earth, many other scientists that followed him were able to expand on his discoveries. Even Christopher Columbus was effected by Eratosthenes's discoveries.
  • 100

    Claudius Ptolemy (100 AD - 170 AD)

    Throughout Ptolemy's life, because it hard to find exact date and times, his work in astronomy, geography, and astrology have helped many in the understanding of everything around us.
  • 1473

    Nicolaus Copernicus (1473-1543)

    sometime before 1514- Copernicus wrote an initial outline of his heliocentric theory.
    It was known only from transcripts from "Nicolai Copernici de hypothesibus motuum colelestium a se constitutis commentariolus."
    This theory allowed us and other scientists to develop more theories that confirmed that our galaxy is heliocentric.
  • 1546

    Tycho Brahe (1546-1601)

    November 1572- Brahe observed a very bright star in the sky and knew that it was something different, like a new star. 1573-He published a small book called, "De Nova Stella," which coined the term nova for a "new" star. The publication of his discovery made him well-known. His discovery allowed us to classify the star as a supernova and it is now numbered SN 1572.
  • 1571

    Johannes Kepler (1571-1630)

    1596- "Mysterium Cosmographicum" was the first published defense of the Copernican System, by Kepler.
    1604- Kepler observed a new nova (SN 1604).
    Kepler's discoveries later lead to his own laws of planetary motion which help people today learn and understand more about our universe and how our solar system works.

  • Sir Isaac Newton (1642-1726)

    1687- "mathematical Principles of Natural Philosophy," laid the foundations of classical mechanics.
    Also in this year Newton published "The Principia" where he stated his 3 laws of motion.
    These 3 laws of motion have since further scientific observations and discoveries.

  • Albert Einstein (1879-1955)

    1907-1915- Einstein developed the theory of General Relativity.
    This theory gives us our current understanding of black holes.