Ancient Astronomers

By 704545
  • 240 BCE

    Eratosthenes accurately measures the Earth's circumfrence.

  • 150

    Claudius Ptolemy' geocentric model

    Ptolemy creates a supposed model of the universe, where he puts the Earth in the center, not the Sun.
  • 1543

    Nicolaus copernicus's heliocentric theory

    Copernicus was believed to be the first person to propose that the sun was the center of our solar system, not Earth.
  • 1572

    Tycho Brahe's accurate observations of stars and planets.

    Brahe made the most precise observations of stars using tools before the creation of the telescope.

  • Johannes Keplar's laws of planetary motion.

    In 1609, Keplar first published his laws of motion.

  • Isaac Newton's theory of gravity.

    Newton was the first person to use mathematics to discover how gravity worked on Earth.

  • Albert Einstein's theory of relativity.

    Einstein's studies show that the laws of physics are "the same for all non accelerating observers". This helped lead to the theories of the origin of the universe.