Jupiter

THE PLANET

Jupiter was known to the ancient Romans. They named it for the Roman god Jupiter.

It has a mass of about 317.8 Earths and two and a half times the mass of all the other planets in the Solar System put together.

Jupiter is a gas giant that didn't have enough mass to become a star. It would have needed a mass of 60-80 times its present amount to have become a star.

Jupiter is the third brightest object in the night sky. Only the Earth's moon and Venus are brighter.

It is the fastest spinning planet in our Solar System rotating on average once in just under ten hours.

Jupiter has a hurricane which has been going on for over 300 years. It can be seen as a red spot on the planet. This hurricane on Jupiter is three times bigger than the Earth itself.

Jupiter’s Great Red Spot is so loud, it’s acoustic sound waves heat up the surrounding atmosphere to almost 2400 degrees Fahrenheit

An image of Jupiter taken by the Hubble Space Telescope

The temperature in the clouds of Jupiter is -234f (-145c. The temperature near the planet’s center is thought to be about 43,000f (24,000c) —– hotter than the surface of the Sun.

It gives off more heat than it receives from the Sun. Because of this release of heat energy, Jupiter is shrinking at a rate of about 0.8 inches (2 centimetres) each year.

Jupiter is hit by impacting meteors big enough to generate fireballs visible from Earth an average of 6.5 times per year.

Jupiter is sometimes called a "cosmic vacuum cleaner" because of frequent impacts from asteroids and comets 

Someone who weighs 150 pounds on Earth would weigh a whopping 354 pounds on Jupiter.

Jupiter can have a triple eclipse, in which three moons cast shadows on the planet simultaneously.

MOONS

There are 67 confirmed moons of Jupiter. 59 of these moons are very small at less than 3 miles (5 km) wide

Jupiter has the largest retinue of moons with reasonably secure orbits of any planet in the Solar System.

Galileo first discovered Jupiter's third largest moon, Io, in 1610. Its name comes from Greek mythology, as do the names of all of Jupiter's moons.

Io is the most volcanically active body known. It's volcanoes throw out enough material every 10,000 years to cover the entire surface with a layer about 3 feet (1 metre) thick. So Io is continually turning itself inside out.

Source: Microsoft Encarta '96