Montage by Emily Lakdawalla. The Moon: Gari Arrillaga. Other moons data: NASA/JPL. Processing by Ted Stryk, Gordan Ugarkovic, Emily Lakdawalla, and Jason Perry.
The Solar System's Major Moons
The Solar System contains 18 or 19 natural satellites of planets that are large enough for self-gravity to make them round. (Why the uncertain number? Neptune’s moon Proteus is on the edge.) They are shown here to scale with each other. Two of them are larger than Mercury; seven are larger than Pluto and Eris. If they were not orbiting planets, many of these worlds would be called “planets,” and scientists who study them are called “planetary scientists.”
Permission is freely granted to reuse this graphic for educational purposes, though we would like to hear from you if you do!
Here are three alternative layouts of this graphic, without text. Email me if you wish me to add text, or to arrange them differently.