Timeline of Discoveries of Models of the Universe

By KELISEB24
  • Eudoxus and a geocentric universe
    500 BCE

    Eudoxus and a geocentric universe

    The ancient Greek mathematician Pythagoras suggested that the Earth is spherical
  • Ptolemy and epicycles
    150 BCE

    Ptolemy and epicycles

    Ptolemy developed Aristotle’s geocentric theory of the universe in about 150 CE. Ptolemy knew that the planets don’t appear to orbit in perfect circles around the Earth.[
  • Aristotle and a finite, eternal, and geocentric universe
    4 BCE

    Aristotle and a finite, eternal, and geocentric universe

    The ancient Greek philosopher Aristotle extended Eudoxus’ model of the universe in the 4th century BCE. Aristotle’s model of the universe was also geocentric, with the Sun, Moon, planets, and stars all orbiting the Earth inside of Eudoxus’ spheres.
  • A heliocentric universe
    1543

    A heliocentric universe

    The Polish astronomer Nicolaus Copernicus reintroduced the idea of a heliocentric universe in On the Revolutions of the Celestial Spheres, first published in 1543.