Saturn has 82 known moons – more than any other planet at the publication time of this article. Of these, twenty were discovered in the last year. Most are just a few miles across. But the larger ones are some of the most fascinating moons of the solar system.
Known for its stunning system of rings, Saturn is truly a gem of the solar system. Although Jupiter, Uranus, and Neptune also have rings, only Saturn’s are easily visible from Earth and are an icon of astronomy. Yet these rings were unknown until the 1600s. For the first five and a half millennia, Saturn was simply the slowest of the five “wandering stars.” The invention of the telescope in 1608 paved the way for more advanced telescopes, eventually allowing astronomers to see Saturn in all its splendor.
Galileo’s most remarkable discovery happened when he pointed his telescope at the planet Jupiter. He found that Jupiter had moons! No one had conceived of the possibility that other planets could have moons that orbit the planet, just as Earth’s moon orbits Earth.
Jupiter is the largest planet in the solar system – over ten times the size of Earth in diameter. Like the sun, it is an enormous ball of hydrogen and helium gas with smaller amounts of other elements held together by its own gravity. Although hydrogen and helium are the two lightest elements, Jupiter has so much of them that its mass is greater than the rest of the planets combined, and yet is only 0.1% the mass of the sun. The pressure of the gases increases as we dive deeper into Jupiter, and at some point, they are forced into a liquid state. But Jupiter has no solid surface.