1846
Neptune is found. Johann Galle found Neptune just where Urbain Le Verrier had calculated it should be, using maths alone.
Wikipedia: NeptunePhoto: NASA / Voyager 2 / PDS / OPUS / Ardenau4 / Wikimedia Commons (CC0)
On this day
23 September in history.
5 moments from 1122 to 2002: discovery, creativity and courage, each with a source to read more.
5 moments
More from 23 September
1122
The Concordat of Worms
The Pope and the Holy Roman Emperor agreed a compromise that ended a long quarrel over who chose bishops.
Photo: Urkunde_Wormser_Konkordat.jpg : Unknown Unknown Original uploader was DALIBRI at de.wik… / Wikimedia Commons (Public domain)
1905
A peaceful parting
Norway and Sweden signed an agreement in Karlstad to end their union peacefully.
Wikipedia: Dissolution of the union between Norway and Sweden
Photo: Visit Karlstad / Wikimedia Commons (CC BY 3.0)
1997
U2 in Sarajevo
U2 played to tens of thousands in Sarajevo, the first big concert in the city after the war.
Wikipedia: U2Wikipedia: PopMart Tour
Photo: Remy / Wikimedia Commons (CC BY 4.0)
2002
Firefox's first version
The first version of the browser that became Firefox was released, made by volunteers.
Photo: Wikipedia home page: Wikimedia Foundation Safari: Apple Inc. / Wikimedia Commons (Public domain)
Moments chosen for discovery, creativity and courage. Each one links to a source where you can read more; photos are credited to their owners.