In Roman mythology, Jupiter was the King of the Gods and that's how the planet got its name. Jupiter dwarfs all other planets in this solar system and could easily hold each of them inside. Technically, no single person discovered Jupiter since it's so massive it can be seen from Earth with the naked eye. A telescope, which was a rare item in the seventeenth century, was used by Galileo in 1610 and he discovered four of Jupiter's moons. It wasn't until the early 1970s when NASA launched the Pioneer 10 and 11 probes to take a closer look at the giant planet. Here are some things astronomers know today about Jupiter.
The Composition of Jupiter
Beneath the swirling reddish-brown and white bands of clouds lies an entirely gaseous atmosphere of hydrogen and helium. There are smaller amounts of ammonia, methane, and carbon monoxide. A distinctive feature is the Great Red Spot, a gigantic storm akin to a hurricane that has raged for centuries. It rotates counterclockwise and it's not known for sure what causes the deep red color, but one idea is that phosphorus compounds rise to the surface and turn red when exposed to ultraviolet radiation.
Further below, about one-third of the way to the core, the temperature soars and liquid hydrogen turns into liquid metallic hydrogen. This is believed to be the source of Jupiter's enormously powerful magnetic field. Protons and electrons are trapped in the field and produce lethal amounts of radiation.
Jupiter's Moons
Jupiter has more moons than any other planet in this solar system. There are sixty-three in total. The largest and most well known are:
- Europa
- Callisto
- Ganymede
- Io
These four are known as the Galilean moons. Europa is one of the more intriguing moons. It has a grooved terrain, making it look like a cracked eggshell. This is in fact a huge ice-sheet which covers the entire moon, pointing to the possibility of a liquid ocean underneath the crust. Callisto is heavily cratered, and shows no sign of geological activity. The impact site called Valhalla is a signature characteristic of Callisto.
Ganymede is large enough to be considered a planet; however, it isn't because it orbits Jupiter and not the sun. The outer crust of Ganymede is likely made of ice. Resembling a pizza, Io is the fifth closest moon to Jupiter and experiences intense volcanic activity.
Future Missions to Jupiter
The Europa Jupiter System Mission is a collaborative effort between NASA and the European Space Agency. Robotic orbiters will be sent to conduct unprecedented studies of Jupiter and its Galilean moons. The two crafts will launch in 2020 and reach Jupiter in 2026.
Reference:
The Universe and Beyond by Terence Dickinson, Firefly Books Ltd, 2004
Scott Hayden - Since joining Suite101 in early 2007, I've contributed articles about travel, history and health. My speciality is writing about workplace ...
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