The outer planets of our solar system are Jupiter, Saturn, Uranus, and Neptune. They are also known as the gas giants or Jovian planets. These planets are much larger than the inner planets and are made primarily of gases and liquids. They have thick gaseous outer layers and liquid interiors. The outer planets are so much larger than the inner planets that they make up 99 percent of the mass of the celestial bodies that orbit the Sun. The outer planets have similar characteristics to one another, such as numerous moons and planetary rings. For example, Jupiter has at least 79 moons, Saturn has at least 82 moons, Uranus has at least 27 moons, and Neptune has at least 14 moons. The outer planets are much farther from the Sun than the inner planets and are composed primarily of hydrogen and helium, with other ingredients such as water, ammonia, and methane.