- MEAN RADIUS: 69911 km
- MASS: 317.8 (Earth=1)
- DENSITY: 1.31 (g/cm^3)
- GRAVITY: 2.34 (Earth=1)
- ORBIT PERIOD: 11.86 (Earth years)
- ROTATION PERIOD: .414 (Earth days)
- SEMIMAJOR AXIS OF ORBIT: 5.2 au
- ECCENTRICITY OF ORBIT: 0.004

Named after Jove, the chief god of Roman mythology, Jupiter is the fifth planet from the Sun and the largest planet in Earth's solar system. Besides the Sun, the Moon, and Venus, Jupiter is the brightest object in Earth's sky, often mistaken as a star. Jupiter is more than three times brighter than Sirius, the brightest star.

The Italian scientist, Galileo Galilei was the first astronomer to view Jupiter through a telescope. While viewing Jupiter, he observed four satellites orbiting the planet, which lent credence to the Copernican theory that the Earth and other planets revolve around the Sun. Previously, many people held to the belief, developed by 2nd century astronomer, Ptolemy, that everything revolved around the Earth. Galileo's discovery was a major step forward for astronomy.

Jupiter's satellites are mostly named for his mythological lovers. Many smaller moons have been discovered recently, but are as yet unnamed.

### Jupiter Satellites:

**Metis**

*Distance (000km) 128 - Radius (km) 20 - Mass (kg) 9.56e16 - Discovered By & Year Synnott 1979***Adrastea**

*Distance (000km) 129 - Radius (km) 10 - Mass (kg) 1.91e16 - Discovered By & Year Jewitt 1979***Amalthea**

*Distance (000km) 181 - Radius (km) 98 - Mass (kg) 7.17e18 - Discovered By & Year Barnard 1892***Thebe**

*Distance (000km) 222 - Radius (km) 50 - Mass (kg) 7.77e17 - Discovered By & Year Synnott 1979***Io**

*Distance (000km) 422 - Radius (km) 1815 - Mass (kg) 8.94e22 - Discovered By & Year Galileo 1610***Europa**

*Distance (000km) 671 - Radius (km) 1569 - Mass (kg) 4.80e22 - Discovered By & Year Galileo 1610***Ganymede**

*Distance (000km) 1070 - Radius (km) (000km) 2631 - Mass (kg) 1.48e23 - Discovered By & Year Galileo 1610***Callisto**

*Distance (000km) 1883 - Radius (km) (000km) 2400 - Mass (kg) 1.08e23 - Discovered By & Year Galileo 1610***Leda**

*Distance (000km) 11094 - Radius (km) 8 - Mass (kg) 5.68e15 Kowal - Discovered By & Year 1974***Himalia**

*Distance (000km) 11480 - Radius (km) (000km) 93 - Mass (kg) 9.56e18 - Discovered By & Year Perrine 1904***Lysithea**

*Distance (000km) 11720 - Radius (km) 18 - Mass (kg) 7.77e16 - Discovered By & Year Nicholson 1938***Elara**

*Distance (000km) 11737 - Radius (km) 38 - Mass (kg) 7.77e17 - Discovered By & Year Perrine 1905***Ananke**

*Distance (000km) 21200 - Radius (km) 15 - Mass (kg) 3.82e16 - Discovered By & Year Nicholson 1951***Carme**

*Distance (000km) 22600 - Radius (km) 20 - Mass (kg) 9.56e16 - Discovered By & Year Nicholson 1938***Pasiphae**

*Distance (000km) 23500 - Radius (km) (000km) 25 - Mass (kg) 1.91e17 - Discovered By & Year Melotte 1908***Sinope**

*Distance (000km) 23700 - Radius (km) 18 - Mass (kg) 7.77e16 - Discovered By & Year Nicholson 1914*