ancient astronomers

  • 240 BCE

    Eratosthenes

    He calculated the size of Earth with good accuracy. This is important because it makes everything we do today more accurate.
  • 127 BCE

    Claudius Ptolemy

    He discovered that Earth was centered in the middle and the Moon, Mercury, Venus, and the Sun all revolved around Earth. This is important because it helped form the basis of our understanding of the motions of stars and planets for over a thousand years.
  • 1543

    Nicolaus Copernicus

    He proposed that Earth and other planets revolve around the Sun. This realization helped to further our understanding of our place in the world.
  • 1577

    Tycho Brahe

    He proved that comets existed outside of the atmosphere. He corrected false theories that were made and got things on track in the right direction.
  • Johannes Kepler

    He discovered that the Earth and planets travel the Sun in elliptical orbits. This helps scientists today understand the movements of Earth better and temperatures.
  • Sir Isaac Newton

    He discovered universal gravitation. This is important because it proved that certain things could be described by the same principles.
  • Albert Einstein

    He discovered the theory of relativity. This was important because it helped to further research in astrophysics and cosmology.