The brief overview of the solar system that we read online or in academic books does not explain its complexity. Most of us think of the sun and the eight planets when we think of the solar system. But what if I tell you some of the natural satellites (moons) have sizes comparable to the smaller planets? Two moons are even larger than Mercury. The following is a list of the top 10 largest moons in the solar system. Ganymede, a moon of Jupiter is the largest moon in the solar system.
Top 10 largest moons in the solar system
| Rank | Moon | Planet | Mean radius |
|---|---|---|---|
| 1 | Ganymede | Jupiter | 2,631 km |
| 2 | Titan | Saturn | 2,575 km |
| 3 | Callisto | Jupiter | 2,410 km |
| 4 | Io | Jupiter | 1,821 km |
| 5 | Earth’s moon | Earth | 1,740 km |
| 6 | Europa | Jupiter | 1,561 km |
| 7 | Triton | Neptune | 1,353 km |
| 8 | Titania | Uranus | 789 km |
| 9 | Rhea | Saturn | 764 km |
| 10 | Oberon | Uranus | 760 km |
Ganymede
Ganymede, Jupiter’s largest moon is the largest moon in the solar system. It has a mean radius of 2,631 km, meaning it is larger than Mercury which has a mean radius of 2,440 km. The only known moon with its own magnetic field, Ganymede has a metallic iron core and a thin atmosphere composed mainly of oxygen. Ganymede is also the most massive natural satellite.
It was discovered by Galileo Galilei on January 7, 1610.
Titan
Titan is the second-largest moon in the solar system. It is Saturn’s largest moon and has a mean radius of 2,575 km. Just like Ganymede, Titan has a larger radius than Mercury but is less massive.
Titan is the only known moon where liquids exist on surface in the form of rivers, lakes, seas, and other water bodies. It has a substantial atmosphere composed mainly of Nitrogen and Methane. Titan was discovered by Christiaan Huygens on March 25, 1655.
Callisto
Callisto comes at number three on this list. It is the second-largest moon of Jupiter with a mean radius of 2,410 km. It is just slightly smaller than Mercury. It was discovered on the same day as Ganymede by Galileo Galilei.
Io
Io is the innermost large moon of Jupiter. It has a mean radius of 1,821 km making it the fourth-largest moon in the solar system. It was also discovered by Galileo Galilei. With a mean density of 3,530 kg / m3, it is the densest moon on this list.
Earth’s moon
Coming at number five on this list, Earth’s moon has a mean radius of 1,740 km. Earth’s moon has an almost negligible atmospheric pressure of 3 x 10-15 bar. It is much denser than Ganymede, Callisto, and Titan.
Fun facts
- The four largest moons of Jupiter are referred to as Galilean moons – Io, Europa, Ganymede, and Callisto.
- Mercury and Venus are the two planets with no known moons.
- Saturn has the highest number of known moons, 146.
- Jupiter has 95 known moons.
- Earth’s Moon is the brightest object in our night sky.