Jupiter has many satellites, 16 of which have a diameter of at least 6 miles. The four main moons of Jupiter are Io, Europa, Ganymede and Callisto, all discovered in 1610 by Galileo and referred to as the "Galilean Moons".
Jupiter was named by the Romans after their King of Gods.

Amazing as it may seem scientists have speculated that life on Jupiter is possible. This would occur beneath the cloud cover where room temperature conditions exist, these lifeforms would be airborne although this theory is thought to be highly speculative.

A magnetic field is created by electricity generated in the core of a planet or other body, forming a magnetic force which surrounds the object. When charged particles from the sun interact with the field a magnetosphere is formed. Earth’s magnetosphere extends tens of thousands of kilometres into space and is extremely important to our planet, if it didn’t exist charged particles from the sun would strip away most of our atmosphere.

What makes Jupiter’s magnetosphere stand out is the enormity of its power and size, it is by far the largest entity in the solar system. If it were visible it would be many times larger in the night sky than the moon. It is so enormous it reaches the outer orbit of Saturn 450 million miles away (724 million km). It creates 10 million amps of electricity which strips away 1000 kilograms of material from one of its nearest moons, Io, every second. Jupiter’s magnetic field captures solar winds from the sun creating one of the most powerful radiation environments in the solar system, a human exposed to these levels of radiation would die within minutes.

When charged particles from the sun get funnelled down its magnetic field and hit the upper atmosphere Aurora are created, such as the ones seen at the North and South poles on Earth, only on Jupiter they are a thousand times more powerful. Radio signals are also created from Jupiter’s magnetosphere which can be picked up with ordinary AM radios on Earth.

Aurora at Jupiter's Pole

Voyager 1 approaching Jupiter

Jupiter with Io in foreground

Diameter: 89,000 miles (143,000 km)
Average Distance from Sun: 484 million miles (779 million km)
Orbital Period: 12 years
Rotation Period: 9.93 hours
Moons: 63

Maximium Temperatures: 24,000C (43,000F) (Core)
Minumum Temperatures: -145C (-230F) (Cloud Tops)

Gravity: 20.87 m/s² (2.14 x Earth's Gravity)
Density: 1.33 g/cm³ (24% Earth's Density)
Mass: 1.8987 x 10²⁷ kg (318 x Earth's Mass)
Volume: 1.4255 x 10¹⁵ km³ (1316 x Earth's Volume)

Atmosphere: 86% Hydrogen, 14% Helium, 0.3% Methane, 0.026% Ammonia, 0.003% Hydrogen deuteride, 0.0006% Ethane, 0.0004% water.

Diameter: 7,926 miles (12,756 km)
Average Distance from Sun: 93 million miles (150 million km)
Orbital Period: 365.24 days
Rotation Period: 23.934 hours
Moons: 1

Maximium Surface Temperatures: 58C (136F)
Minumum Surface Temperatures: -88C (-126F)

Gravity: 9.766 m/s²
Density: 5.515 g/cm³
Mass: 5.9737 x 10²⁴ kg
Volume: 1.0832 x 10¹² km³

Atmosphere: 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, water vapour makes up around 0.4% of Earth's atmosphere depending on climatic conditions.