Neptune is a gas giant and an outer planet. In the solar system, the three other gas giants are Uranus, Jupiter and Saturn. Gas giants are massive planets that have a composition of mainly gases.
Neptune's atmosphere contains the gases hydrogen, helium and methane. Methane is responsible for the planet’s blue color. Another striking feature of Neptune is its supersonic winds. At a distance of 4.5 billion kilometers, this planet is the farthest from the sun of the planets in the solar system. Neptune has 13 known moons and six rings. The period of revolution of Neptune is 165 Earth years. Its period of rotation is about 16 Earth hours.