There are 67 known
moons of Jupiter. This gives
Jupiter the largest number of
moons with reasonably secure orbits of any planet in the
Solar System. The most massive of them, the four
Galilean moons, were discovered in 1610 by
Galileo Galilei and were
the first objects found to orbit a body that was neither Earth nor the Sun. From the end of the 19th century, dozens of much smaller Jovian moons have been discovered and have received the names of lovers, conquests, or daughters of the
Roman god Jupiter, or his
Greek equivalent,
Zeus. The Galilean moons are by far the largest and most massive objects in orbit around Jupiter, with the remaining 63 moons and
the rings together comprising just 0.003% of the total orbiting mass.