History of Astronomy

  • 322 BCE

    Aristotle

    Aristotle
    Believed the Earth and the other planets were spheres. He also believed that the Earth was in the middle of the universe and all planets orbited around Earth.
  • 120 BCE

    Hippachus

    Hippachus
    Greek, wrote first star catalog, calculated distance between Earth and moon.
  • 170

    Ptolemy

    Ptolemy
    Wrote a book (star catalog) that included eclipses and also believed that the planets orbited Earth.
  • 1473

    Copernicus

    Copernicus
    Made the heliocentric model (sun is in the center). Made scientific method.
  • 1564

    Tycho Brahe

    Tycho Brahe
    Made most accurate observatory and recorded data for 20 years. Believed the universe was both ptolemaic and copernican so he thought that the planets orbited around the sun but the sun orbited around the Earth.
  • 1564

    Galileo

    Galileo
    Made his own telescope and found that the moon had craters, valleys and mountains. He also found sunspots on Venus and Moons orbiting Jupiter. He called the Io, Ganymede, Callisto and europa. He proved the stars did not have invisible shields and proved that not everything orbited around Earth.
  • 1570

    Lippershey

    Lippershey
    Made a telescope 3 times the magnification.
  • 1571

    Kepler

    Kepler
    Brahe’s assistant, also discovered the orbit of the planets were oval not circular
  • Cassini

    Cassini
    Discovered the division of the rings of Saturn and 4 of Saturn’s moons. Also discovered Mars and Jupiter’s rotation periods.
  • Isaac Newton

    Isaac Newton
    Made the 3 laws of motion. Invented reflecting telescope.
  • Herchel

    Herchel
    Discovered Uranus and the two moons. He also found water on Mars and more moons on Saturn. He found out that color can be seen through a prism and temperature affects color.
  • Lowell

    Lowell
    Found pluto and studied the canalis on mars. Built Lowell Observatory in Flagstaff, AZ.
  • Hertzsprung

    Hertzsprung
    One of the inventors of the Hertzsprung_Russell diagram. Shows correlation between absolute magnitude and the spectrilight star.
  • Einstein

    Einstein
    Theory of Relativity and gravitation.
  • Hubble

    Hubble
    Discovered the universe is expanding using stars. Hubble’s law was galaxies are moving away from each other. The idea is the basis of the Big Bang Theory.
  • Jansky

    Jansky
    Discovered the radio waves are emanating from space. Radio waves are the longest type of energy waves.
  • Gagarin

    Gagarin
    First human to orbit Earth from Russia.
  • Sputnik

    Sputnik
    The Soviets sent the first satellite to orbit Earth in space. Also when NASA was formed. This is when science became important in school.
  • Glenn

    Glenn
    First American to orbit Earth. Orbited 3 times.
  • Armstrong

    Armstrong
    First person to walk on the moon.
  • Apollo Missions

    Apollo Missions
    Take people on the moon and bring them back safely.
  • First Space Shuttle

    First Space Shuttle
    First American space shuttle flight. (Space stations start being built)
  • Mars Pathfinder Expedition

    Mars Pathfinder Expedition
    To explore mars. (2 years)
  • Cassini Orbiter

    Cassini Orbiter
    Orbited around the rings of Saturn, took 30 years.
  • Falcon Heavy

    Falcon Heavy
    Rocket launched into space with a Tesla.