What Planet Has A Density Of Less Than 1?

Saturn is the only planet in the solar system which has a density of less than one. If it were to be placed in water it would actually float. That's because its density is less than that of water. The density of Saturn is sometimes reported as being around .97 gm/cc, which is still less than water. It is mostly the outer planets within the solar system which are less dense. Planets on the inside are far denser. The earth is the densest planet followed closely by Mercury and then Venus. Mars is also pretty dense. Other planets like Pluto, Uranus, Neptune and Neptune are besides Saturn the lesser dense planets. Saturn comes second in terms of mass, superseded by Jupiter. Temperature on the surface of different planets is determined based on their proximity to the sun.