What is the largest moon of Saturn?
Quick answer
Titan is Saturn’s largest moon and the second-largest moon in the solar system, after Jupiter’s Ganymede. It’s about 5,150 km (3,200 miles) across, larger than the planet Mercury. It’s the only moon with a thick atmosphere and the only place besides Earth known to have liquid lakes and seas on its surface, made of methane and ethane.
Titan at a glance
| Diameter | ~5,150 km |
| Discovered | 1655, by Christiaan Huygens |
| Surface temperature | About −179°C (−290°F) |
| Atmosphere | Mostly nitrogen, thicker than Earth’s |
| Surface liquids | Methane and ethane lakes and seas |
A strange, Earth-like world
On Titan, the “water cycle” uses methane instead of water. Methane rains from orange clouds, flows in rivers and collects in seas such as Kraken Mare. The surface has dunes, mountains and riverbeds, much like Earth, but frozen water ice acts like rock. Scientists also think Titan hides an ocean of liquid water deep beneath its crust.
The largest moons in the solar system
| Rank | Moon | Planet | Diameter |
|---|---|---|---|
| 1 | Ganymede | Jupiter | ~5,268 km |
| 2 | Titan | Saturn | ~5,150 km |
| 3 | Callisto | Jupiter | ~4,821 km |
| 4 | Io | Jupiter | ~3,643 km |
| 5 | Our Moon | Earth | ~3,475 km |
Missions to Titan
- Cassini–Huygens (1997–2017): In 2005, the Huygens probe landed on Titan, the most distant landing ever made.
- Dragonfly: NASA’s planned nuclear-powered drone helicopter is scheduled to launch in the late 2020s and fly between sites on Titan in the 2030s.
How many moons does Saturn have?
Saturn has more than 270 officially recognized moons, the most of any planet, after many small new ones were confirmed in recent years.
For another giant planet’s records, see the largest planet. For an ice giant tipped on its side, see Uranus.
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