In the outer Solar System are the four remaining planets Jupiter, Saturn, Uranus, and Neptune. Made primarily of gasses these planets are called gas giants. Gas giants are massive and consist of a thick atmosphere and a dense molten core. Because the gas giants aren't made of rock and solid matter they don't have solid surfaces like the terrestrial planets. Therefore landing on one would be impossible.
the outer planets
Jupiter is the fifth planet from the Sun and the largest planet in the Solar System. It is a giant planet with a mass one-thousandth of that of the Sun, but is two and a half times that of all the other planets in the Solar System combined.
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Named after the Roman god of agriculture, its astronomical symbol represents the god's sickle.
Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System.