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Pluto

dwarf planet in the Solar System

13 dated entries naming Pluto, drawn from 12 separate years between 561 BCE and 2015 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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6th century BC

  • 561 BCEAll eight solar system planets, including the now redefined dwarf planet Pluto, fall into planetary alignment.source

15th century

  • 1483April 30 – Pluto moves inside Neptune's orbit until July 23, 1503, according to modern orbital calculations. At the time, neither planet has been discovered by Earth astronomers. The event of Pluto being closer to the Sun than Neptune will happen again during the period lasting from 1979 to 1999.source

16th century

  • 1503July 23 – Orbital calculations suggest that on this day Pluto moves outside Neptune's orbit, remaining there for 233 years.source

17th century

  • 1618July 20 – Pluto reaches its second most recent aphelion, according to sophisticated mathematical calculations. The next one occurs in 1866, and the following one will occur in 2113.source

19th century

  • 1866June 5 – Calculations indicate Pluto (not known at this time) reaches its only aphelion (furthest point from the Sun) between 1618 and August 2113.source

20th century

  • 1915March 19 – Pluto is photographed for the first time, but is not recognised for what it is.source
  • 1930February 18 – While studying photographs taken in January, Clyde Tombaugh confirms the existence of Pluto, a celestial body considered a planet until redefined as a dwarf planet in 2006.source
  • 1978June 22 – Charon, a satellite of Pluto, is discovered.source
  • 1979February 7 – Pluto moves inside Neptune's orbit for the first time since either was known to science.source
  • 1999February 11 – Pluto moves along its eccentric orbit further from the Sun than Neptune. It had been nearer than Neptune since 1979, and will become again in 2231.source

21st century

  • 2006August 24 – The International Astronomical Union defines 'planet' at its 26th General Assembly, removing Pluto's status as a planet and reclassifying it as a dwarf planet 76 years after its discovery. Ironically, this was in the same year when NASA sent its first probe to the celestial body.source
  • 2006January 19 – NASA launches the first interplanetary space probe to Pluto, the New Horizons.source
  • 2015July 14 – NASA's New Horizons spacecraft performs a close flyby of Pluto, becoming the first spacecraft in history to visit the distant world.source

Named in the same entries