Discovery · 1610 CE
The Galilean Moons of Jupiter
History of Astronomy
Overview
In January 1610 Galileo saw four points of light beside Jupiter that changed position night after night — moons orbiting another world.
Why it matters
Direct proof that not everything orbits the Earth, undermining the geocentric model.
Credit
Objects & facilities
Bearing on theory
Reported in
Knowledge connections
- Discovered byGalileo Galilei
- Part ofThe Scientific Revolution
- Related toJupiter
- Related toIo
- Related toEuropa
- Related toGanymede
- Related toCallisto
- RefutedThe Geocentric Model
- Introduced bySidereus Nuncius
Sources & references
The primary and reference sources this topic draws on.
- BritannicaEncyclopaedia Britannica
General reference for the history of astronomy, biographies, and cultural context.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.