Neptune: Planet 8

		Diameter		30,775 miles (49,528 km)
		Average Distance from Sun		2,793,100,000 miles (4,497,100,000 km)
		Planet Composition		liquids surrounding a rocky core
		Atmosphere		hydrogen, helium, methane, water vapor
		Temperature		-330°F (-200°C)
		Number of Moons		8
		Orbital Period		59,800 days (163.8 years)
		Period of Rotation		16 hours 3 minutes

Neptune is four times larger than the planet Earth, but it is the smallest of the gas giants.

Neptune's blue color is caused by methane gas in the atmosphere. The streaks and bands on Neptune are caused by storms and clouds that may travel at up to 1,300 miles per hour -- the fastest measured on any planet in the solar system.

Neptune has thin rings that are not visible from Earth. Although scientists had suspected that rings existed, we did not know for sure until Voyager 2 photographed them when it flew past in August 1989.

Triton is Neptune's largest moon -- it is even bigger than the planet Pluto.

Triton is made of rock and ice with a thin atmosphere. Its surface is covered with patterns where the ice melted and refroze. Underground heat and pressure cause geysers that blast material, such as liquid nitrogen, through cracks on the moon's surface.

Triton, Neptune's largest moon