On the night of 7 January 1610 Galileo Galilei, in Padua, pointed his improved telescope at Jupiter and noticed three small stars in a line beside it. Over the next nights he saw them change position and realised that they were moons circling the planet; a fourth appeared on 13 January. He published the discovery in March in the short book Sidereus Nuncius, which also described the mountains of the Moon and countless new stars in the Milky Way. Since not everything orbited the Earth, the finding gave strong support to the Copernican system. The four bodies, Io, Europa, Ganymede and Callisto, are still called the Galilean moons.
Before and after
- 7 January 1610Discovery of Io
- 7 January 1610Discovery of Callisto
- 7 January 1610Discovery of Europa
- 7 January 1610Discovery of Ganymede
- 7 January 1610Galileo discovers the moons of Jupiter
- 18 July 1610Death of Caravaggio
- 19 May 1611Birth of Innocent XI
- from 1613 to 1762House of Romanov
- 1614Founding of Tirana
More in Universe & space
- 11 November 1572Tycho's Supernova
- 1576Founding of Uraniborg
- October 1604Kepler's Supernova appears in the constellation Ophiuchus
- 8 October 1604SN 1604
- 9 December 1743Discovery of Great Comet of 1744
- 25 December 1758Halley's Comet returns as predicted
The era
This moment belongs to the Early modern world (1500 CE to 1760 CE), voyages, printing and new ideas. You can also browse everything in the 17th century.