Planet and Moon Sizes

The solar system is so vast that it's difficult to visualize how big some of the planets are. For example, Jupiter is so much bigger than Earth that Earth would fit inside its Great Red Spot. Earth's moon is unusual because it's a respectable fraction of the size of its primary; it's gigantic compared to Mars's moons, Phobos and Deimos, which look like specks next to it, and it's about as big as Io, one of the largest moons of Jupiter.

These pages are intended to convey something about the size of the other planets and their moons by comparing them to each other, and to Earth and its moon. If your browser is able to scale inline images, then the two images on each page will appear at the correct relative sizes on your screen.

To see any size comparisons, not just the ones pregenerated here, try the appropriate page of my Never Ending Quiz.


Bob Kanefsky Kanef@Ptolemy.ARC.NASA.gov
Responsible NASA official: Sonie Lau