The surface gravity of Neptune is 36.6 feet per second squared, or 11.5 meters per second squared. A person weighing 100 pounds on the Earth would weigh about 114 pounds on Neptune.
The mass of Neptune is more than 17 times greater than the Earth. By comparison, if the Earth were reduced to the size of a nickel, Neptune would be the size of a baseball.
Neptune is a gas giant composed of water, ammonia and methane surrounding an Earth-sized solid core. The atmosphere is mostly hydrogen, helium and methane.
Neptune is the eighth planet and is the farthest from the sun. It was the first planet whose existence was predicted from mathematical calculations before it was observed through a telescope.