1930 Pluto discovered
Source: https://www.history.com/this-day-in-history/pluto-discovered
Source: https://www.history.com/this-day-in-history/pluto-discovered
Source: https://www.nrl.navy.mil/accomplishments/rockets/vanguard-project
Source: https://www.wired.com/2010/02/0216cbbs-first-bbs-bulletin-board/
Source: https://www.history.com/topics/holidays/presidents-day
Source: https://www.history.com/topics/valentines-day/valentines-day-facts
Source: https://www.history.com/this-day-in-history/edison-patents-the-kinetograph
Source: https://solarsystem.nasa.gov/missions/near-shoemaker/in-depth/
Source: https://www.history.com/this-day-in-history/ziggy-stardust-makes-his-earthly-debut