Timeline of solar system astronomy

• 2136 BC - Chinese astronomers record a solar eclipse
• 586 BC - Thales of Miletus predicts a solar eclipse
• 350 BC - Aristotle argues for a spherical Earth using lunar eclipses and other observations
• 280 BC - Aristarchus uses the size of the Earth's shadow on the Moon to estimate that the Moon's radius is one-third that of the Earth
• 200 BC - Eratosthenes uses shadows to determine that the radius of the Earth is roughly 6,400 km
• 150 BC - Hipparchus uses parallax to determine that the distance to the Moon is roughly 380,000 km
• 134 BC - Hipparchus discovers the precession of the equinoxes
• 1512 - Nicholas Copernicus first states his heliocentric theory in Commentariolus
• 1543 - Nicholas Copernicus shows that his heliocentric theory simplifies planetary motion tables in De Revolutionibus de Orbium Coelestium
• 1577 - Tycho Brahe uses parallax to prove that comets are distant entities and not atmospheric phenomena
• 1609 - Johannes Kepler states his first two empirical laws of planetary motion
• 1610 - Galileo Galilei discovers Callisto, Europa, Ganymede, and Io
• 1610 - Galileo Galilei sees Saturn's planetary rings but does not recognize that they are rings
• 1619 - Johannes Kepler states his third empirical law of planetary motion
• 1655 - Giovanni Cassini discovers Jupiter's great red spot
• 1656 - Christian Huygens identifies Saturn's rings as rings and discovers Titan and the Orion Nebula
• 1665 - Giovanni Cassini determines the rotational speeds of Jupiter, Mars, and Venus
• 1672 - Giovanni Cassini discovers Rhea
• 1672 - Jean Richer and Giovanni Cassini measure the astronomical unit to be about 138,370,000 km
• 1675 - Ole Rømer uses the orbital mechanics of Jupiter's moons to estimate that the speed of light is about 227,000 km/s
• 1705 - Edmund Halley publicly predicts the periodicity of Halley's Comet and computes its expected path of return in 1758
• 1715 - Edmund Halley calculates the shadow path of a solar eclipse
• 1716 - Edmund Halley suggests a high-precision measurement of the Sun-Earth distance by timing the transit of Venus
• 1758 - Johann Palitzsch observes the return of Halley's comet
• 1766 - Johann Titius finds the Titius-Bode rule for planetary distances
• 1772 - Johann Bode publicizes the Titius-Bode rule for planetary distances
• 1781 - William Herschel discovers Uranus during a telescopic survey of the northern sky
• 1796 - Pierre Laplace states his nebular hypothesis for the formation of the solar system from a spinning nebula of gas and dust
• 1801 - Giuseppe Piazzi discovers the asteroid Ceres
• 1802 - Heinrich Wilhelm Olbers discovers the asteroid Pallas
• 1821 - Alexis Bouvard detects irregularities in the orbit of Uranus
• 1825 - Pierre Laplace completes his study of gravitation, the stability of the solar system, tides, the precession of the equinoxes, the libration of the Moon, and Saturn's rings in Mecanique Celeste
• 1843 - John Adams predicts the existence and location of Neptune from irregularities in the orbit of Uranus
• 1846 - Urbain Le Verrier predicts the existence and location of Neptune from irregularities in the orbit of Uranus
• 1846 - Johann Galle discovers Neptune
• 1846 - William Lassell discovers Triton
• 1849 - Edouard Roche finds the limiting radius of tidal destruction and tidal creation for a body held together only by its self gravity, called the Roche limit, and uses it to explain why Saturn's rings do not condense into a satellite
• 1856 - James Clerk Maxwell demonstrates that a solid ring around Saturn would be torn apart by gravitational forces and argues that Saturn's rings consist of a multitude of tiny satellites
• 1866 - Giovanni Schiaparelli realizes that meteor streams occur when the Earth passes through the orbit of a comet that has left debris along its path
• 1906 - Max Wolf discovers the Trojan asteroid Achilles
• 1930 - Clyde Tombaugh discovers Pluto
• 1930 - Seth Nicholson measures the surface temperature of the Moon
• 1950 - Jan Oort suggests the presence of a cometary Oort cloud
• 1951 - Gerard Kuiper argues for an annular reservoir of comets between 40-100 astronomical units from the Sun, the Kuiper belt
• 1977 - James Elliot discovers the rings of Uranus during a stellar occultation experiment on the Kuiper Airborne Observatory
• 1978 - James Christy discovers Charon
• 1978 - Peter Goldreich and Scott Tremaine present a Boltzmann equation model of planetary-ring dynamics for indestructible spherical ring particles that do not self-gravitate and find a stability requirement relation between ring optical depth and particle normal restitution coefficient
• 1988 - Martin Duncan, Thomas Quinn, and Scott Tremaine demonstrate that short-period comets come primarily from the Kuiper Belt and not the Oort cloud

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