Neptune is the farthest of the eight planets from the Sun and is the fourth largest, with a diameter of 49572 kilometers (3.9 times that of Earth). It is one of the four gas giants. If Neptune had a solid surface and you stood on it, you would weigh 12% more than you do on Earth.
Neptune orbits the sun once every 164.79 Earth-years, at an average distance of 30.06 AU (Earth-Sun distances) and with an orbital eccentricity of 0.010, making its orbit more nearly circular than that of any other planet except Venus. Neptune is so far away from the Sun that light from the Sun takes an average of 4 hours 10 minutes 25 seconds to get to Neptune.
Neptune rotates about its axis prograde (in the direction of its solar orbit) once every 16 hours 6.5 minutes, at an axial tilt of 28.31°.