The Outer Planets The outer planets are: Jupiter Saturn Uranus Neptune
The four outer planets are much larger than earth. They do not have solid surfaces. Because of this, they are called the “gas giants”. These four planets have dense atmospheres that have a similar composition to the Sun (mostly hydrogen). They are thought to have solid cores.
Jupiter is the largest planet. It is covered by thick bands of clouds.
Jupiter’s “giant red spot” is actually a huge, swirling storm.
Jupiter has 63 moons! One moon, Ganymede, is larger than Earth. Io has volcanoes. Europa has a frozen, watery ocean!
Saturn is the second largest planet in our solar system. Its rings are made out of orbiting rocks and ice.
Saturn has 46 moons. Four of them are large enough to see with a telescope. Saturn’s moons vary greatly in shape, size and color.
Uranus is very far from the Sun and is very cold. Its most unusual feature is that its axis is tilted to the side. This means that it is really rotating from top to bottom. Scientists think it may have been knocked out of orbit by an asteroid.
At last count, Uranus had a total of 21 moons, many of which were only recently discovered. Its moons tend to be heavily cratered and scarred. Any ideas why this is?
Neptune has clouds and storms that move on its surface, such as the Great Dark Spot. Thirteen moons have been discovered there. The largest is Triton, which appears to have geysers!
Pluto is no longer considered a planet. It has been renamed a “dwarf planet.” Some scientists feel that Pluto is actually more like a meteor in the Kuiper Belt. Others still feel that it is a planet in our solar system.
Pluto lost its planet status due to the fact that it is not thought to be large enough and it has an irregular orbit. Pluto has a body orbiting it called Charon. It was once thought to be either its moon or it could be a “binary planet”. The surfaces of both are solid and have masses less than that of Earth.
Many photos and information about the outer planets has been gathered by the Voyager 2.