Planetarium goers discovered Jupiter’s moons

In the case of Jupiter’s moons, this means that their relative constellation repeats itself after each orbit of Ganymede. Depending on the actual location of celestial bodies, such resonance can, on the one hand, have a stabilizing effect on the motion, but on the other hand, gravitational disturbances can also accumulate.

Strong tides and violent volcanic eruptions

This does not happen with Jupiter’s moons; The orbit of Io, the innermost moon, is stable here. Since this orbit is also slightly eccentric, this results in a very strong tidal force that can affect Io. Jupiter’s large mass, combined with regular changes in distance from Io during a single orbit around the moon, create a strong tidal effect. This is also the reason for the very active volcanic activity on Io, which is unique in this form in the solar system. Jupiter uses tidal force to transfer part of its rotational energy to the small moon in the form of heat, causing its interior to heat up significantly and enabling volcanic activity.

Of course, Galileo Galilei knew nothing about this when he first saw Jupiter’s moons through a telescope. But through his observations, calculations, and jovelabiums, he soon discovered that they were actually objects orbiting Jupiter. So the Earth could not be the center of rotation of all celestial bodies, and Galileo believed that all planets moved around the Sun anyway. However, this heliocentric worldview did not become established until later; He himself could not share this knowledge publicly without getting into trouble with the (ecclesiastical) authorities.