King of the Planets The fifth planet in our solar system is also the largest planet in our system, both in size and mass. Jupiter's diameter of over 85,000 miles is almost twelve times that of Earth and its mass is well over twice as much as all the rest of the planets put together. These facts make it appropriate that the planet is named after the king of all the other gods in ancient Roman mythology. Jupiter is also the first of the gas planets in our system. A gas planet is one that does not have a solid surface like Earth. Instead, you can think of Jupiter, as well as the rest of the gas planets, as being a giant ball of mostly hydrogen and helium. Scientists believe that Jupiter has a small rocky core at its center, but even the core of this giant planet is much larger than our Earth. Jupiter's size not only makes it the largest planet in our solar system, it has also helped us explore the outer planets. Scientists have used the planet's gravity to accelerate spacecraft and send them one their way to Saturn, Uranus and
Jupiters name Comes from the Roman king of the gods. Visited by Pioneer 11, Viking, Galileo and others Ruler of the Night Skies Jupiter's extremely large size has made it a favorite observation subject for professional and amateur astronomers ever since Galileo used his first primitive telescope almost four hundred years ago. Using even a small telescope, you are able to see the distinctive color bands of Jupiter's atmosphere as well as the four large Galilean moons. Using a medium-sized telescope, you should be able to see the Great Red spot just south of Jupiter's equator. In fact, you can see the four