1801: Predicted by the Titius–Bode law, the presence of a body between Mars and Jupiter is confirmed by Giuseppe Piazzi on 1 January. Initially classified as a planet, then as an asteroid in 1802 by Herschel, Ceres eventually joined the category of dwarf planets in 2006.

1954: 1 January marks the entry into service of the Uccle Solar Telescope (USET). Since that date, the instrument has ensured continuous monitoring of our star's activity, forming one of the most stable series of solar observations in Europe.

2000: On the first day of the millennium, the Regional Warning Centre (RWC) Belgium issued its first URSIgram. This historic bulletin formalised space weather monitoring to anticipate the impact of solar storms on our technological infrastructure.