Astronomy Timeline

By mariaasf
  • 2000 BCE

    Lunar eclipse observed at Ur in Mesopotamia.

    Lunar eclipse observed at Ur in Mesopotamia.
    The oldest known recording of a lunar eclipse took place at Ur more than 4000 years ago.
  • 700 BCE

    Hesiod describes practical uses for astronomy.

    Hesiod describes practical uses for astronomy.
    Hesiod's poem The Works and Days contains practical astronomical advice for navigation and for agricultural activities.
  • 585 BCE

    Thales said to have predicted solar eclipse.

    Thales said to have predicted solar eclipse.
    The eclipse took place during a battle between the Lydians and the Persians. They were so stunned by the eclipse they ended the battle.
  • 560 BCE

    Anaximenes proposes model of cosmos.

    Anaximenes proposes model of cosmos.
    In Anaximenes model the stars are fixed to the inside of a solid vault surrounding the Earth. Later Greek astronomers develop this idea into the concept of the celestial sphere.
  • 550 BCE

    Pythagoras and students develop model of solar system.

    Pythagoras and students develop model of solar system.
    The model of Pythagoras used circular paths for the celestial bodies and assumed most celestial bodies are spheres.
  • 400 BCE

    Eudoxus explains retrograde motion.

    Eudoxus explains retrograde motion.
    Eudoxus's explanation involved the rotation of spheres in opposite directions. This geocentric model had the Earth at its center.
  • 350 BCE

    Aristotle argues celestial bodies are spheres.

    Aristotle argues celestial bodies are spheres.
    Aristotle used a number of proofs that the Earth is a sphere, including the observation that its shadow on the Moon during lunar eclipses is always a circle
  • 250 BCE

    Eratosthenes finds circumference of Earth.

    Eratosthenes finds circumference of Earth.
    Eratosthenes uses observations of the altitude of the Sun to find the circumference of the Earth. His estimate may have been accurate to within a few percent.
  • 134 BCE

    Hipparchus discovers precession, prepares stellar catalog.

    Hipparchus discovers precession, prepares stellar catalog.
    Hipparchus compared his own observations with earlier ones to discover precession, the slow change in the direction of the Earth's polar axis. He also made what was probably the first catalog of the positions and brightnesses of the stars.
  • 1 CE

    Building of Bighorn Medicine Wheel.

    Building of Bighorn Medicine Wheel.
    Plains Indians of North America built medicine wheels, monuments made of piles of stones. Alignments in the medicine wheels often pointed toward the direction of sunrise at the winter solstice
  • 1054

    Chinese record supernova that produces Crab Nebula.

    Chinese record supernova that produces Crab Nebula.
    Chinese astronomers observed a supernova that was visible in the daytime. The matter blasted outward by the supernova later became observable as the Crab Nebula.
  • 1066

    Comet Halley considered ill omen for King Harold.

    Comet Halley considered ill omen for King Harold.
    The appearance of Comet Halley in 1066 was considered an ill omen for Harold, King of England. Later that year Harold was killed in the Norman invasion of England.