SpaceThe count changes
These are the numbers in NASA's fact sheet as last updated on 18 March 2025 and read on 12 November 2026. They rise from time to time, because small, faint moons of the giant planets are still being found and confirmed. If you see a different number elsewhere, check the date of that source.
Who has the most?
By this count the eight planets have 416 moons between them. Saturn has by far the most, 274, followed by Jupiter with 95, Uranus with 28 and Neptune with 16. The four small inner planets have only three in all: Earth has one, Mars has two, and Mercury and Venus have none.
Moons worth knowing
- The Moon, Earth's only natural satellite. It is 3,475 km across, 27% of Earth's width.
- Phobos and Deimos, the two small moons of Mars, which NASA says may be captured asteroids.
- Titan and Enceladus of Saturn. Titan is smoggy and has lakes of methane. Enceladus sprays jets of water.
- Triton, the largest moon of Neptune, found seventeen days after the planet itself in 1846.
- Charon, the largest of Pluto's five known moons, about half the size of Pluto.
Rings
All four giant planets have rings: Jupiter, Saturn, Uranus and Neptune. Saturn's are the famous ones. NASA describes Uranus as surrounded by 13 faint rings. None of the four rocky planets has any.
Magnetic fields
The fact sheet lists a global magnetic field for Mercury, Earth and the four giants, and none for Venus and Mars. Earth's field is what makes a compass needle point north.