## ♃ Jupiter

## STATISTICS

### ORBITAL RADIUS

**780 million km **from the Sun (5 times the distance of the Earth from the Sun)

### ORBITAL PERIOD

**12 Earth years**

### DIAMETER

**140,000 km **(11 times the diameter of the Earth)

### ROTATIONAL PERIOD

**9.9 Earth hours**

### MASS

**320** times the mass of the Earth

## Moons

**Jupiter** is known to have (at least) **69 moons**.

(**Edit**: literally two days after I wrote that, the figure jumped to **7****9 moons**. This is why I used the term ‘at least’!)

The four largest are known as the **Galilean moons**, as they were discovered by **Galileo**, in 1610.

Ganymede is larger in diameter than **Mercury**, which also makes it larger than the **Moon**. Indeed, it is the largest moon in the solar system. Callisto and Io are also both larger than the Moon.

(The diameter of Io is 3,600 km, Europa is 3,100 km, Ganymede is 5,300 km and Callisto is 4,800 km. These compare with the diameter of the Moon, which is 3,500 km.)

In terms of mass, Ganymede is about double the mass of the Moon. Both Io and Callisto also have a greater mass than the Moon, but Europa has a smaller mass, despite being larger in volume.