Scientists are finding so many moons of the solar system’s giant planets that they can hardly keep up with them. By the end of last year, Saturn was in the lead, with 146 confirmed moons. Jupiter — the biggest planet — came in second, with 95. But some of its moons are the most amazing of all — worlds with giant volcanoes, or hidden oceans that could host microscopic life.

Most of the moons of both planets are a lot less interesting. They’re basically big chunks of rock and ice. Some of them could be captured asteroids, but most probably are debris from shattered moons.

The population of known moons has exploded in the past decade or two. In part, that’s because modern technology makes it possible to find these tiny, faint objects. Also, scientists are putting a lot more effort into the search. That’s because, while the recent discoveries are all fairly boring on their own, they reveal a lot about the histories of both worlds. In particular, they tell us how the systems of moons and rings may have evolved — producing the busy planetary systems we see today.

Jupiter stands quite near our own moon tonight. It’s to the lower left of the crescent Moon at nightfall. Jupiter looks like a brilliant star — only the Moon and the planet Venus outshine it. It’s a world with plenty of known moons — and probably many more awaiting discovery.

We’ll talk about the Moon and some stellar companions tomorrow.

Script by Damond Benningfield