Solar System

the Sun, its planets and their moons

14 dated entries naming Solar System, drawn from 14 separate years between 280 BCE and 2017 CE. Nothing here is written by us: each line is the sentence a Wikipedia year article used, and the link beside it opens the exact revision.

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3rd century BC

280 BCEAristarchus of Samos 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. He proposes, for the first time, a heliocentric view of the Solar System, but is ignored due to the lack of evidence of the Earth's motion.source

6th century

511Aryabhata, Indian astronomer and mathematician, comes up with concepts of mathematical equations, one of which explains the rotation of the Earth on its axis. This concept is far ahead of its time and he is fairly accurate in his description of it. He also comes up with a lot of other ideas about the Solar System, but many of them are flawed because he considers the Earth to be the center of the universe. Aryabhata is often given credit for coming up with the number zero and using it as a placeholder.source

17th century

1614Astronomer Johannes Kepler soon begins to employ logarithms, in his description of the Solar System.source
1633June 22 – the Roman Catholic Church forces Galileo Galilei to recant his heliocentric view of the Solar System. According to legend, he claims Eppur si muove.source

19th century

1899December 2 – During the new moon, a near-grand conjunction of the classical planets and several binocular Solar System bodies occur. The Sun, Moon, Mercury, Mars and Saturn are all within 15° of each other, with Venus 5° ahead of this conjunction and Jupiter 15° behind.source

20th century

1972March 2 – The Pioneer 10 spacecraft is launched from Cape Kennedy, to be the first man-made spacecraft to leave the Solar System.source
1973April 5 – Pioneer 11 is launched on a mission to study the Solar System.source
1977November 1 – 2060 Chiron, first of the outer Solar System asteroids known as Centaurs, is discovered by Charlie Kowal.source
1983June 13 – Pioneer 10 passes the orbit of Neptune, becoming the first human-made object to leave the vicinity of the major planets of the Solar System.source
1986February 9 – Halley's Comet reaches its perihelion, the closest point to the Sun, during its second visit to the Solar System in the 20th century (the first was in 1910).source
1998November 17 – Voyager 1 overtakes Pioneer 10 as the most distant man-made object from the Solar System, at a distance of 69.419 AU km.source

21st century

2005January 5 – Eris, the most massive known dwarf planet in the Solar System, is discovered by a team led by Michael E. Brown using images originally taken on October 21, 2003, at the Palomar Observatory.source
2012August 25 – The Voyager 1 space probe becomes the first human-made object to successfully exit the Solar System and enter Interstellar space, and to an extent, becoming the first Interstellar probe, pioneering Interstellar exploration.source
2017November 20 – Nature publishes an article recognising the high-velocity asteroid ʻOumuamua as originating from outside the Solar System, i.e. the first known interstellar object.source