Neptune is the solar system's farthest planet from the sun, located an average of 2.79 billion miles away. The circumference of its orbit is 17.56 billion miles, more than 30 times the orbit circumference of Earth. Its volume is 15 trillion cubic miles, more than 57 times the volume of Earth, and its surface area is 2.94 billion square miles, nearly 15 times the surface area of Earth.
A day on Neptune is equivalent to 16.11 hours, or 0.671 Earth days, but a year is equal to 164.79 Earth years. The average temperature on the planet is minus 353 degrees Fahrenheit. Neptune has at least 13 moons and six rings.
The French mathematician Urbain Joseph Le Verrier is credited with discovering Neptune in 1846, although it had been observed as early as 1613 by Galileo, who mistook it for a star. It was named by Johann Galle after the Roman god of the sea in the tradition of the other planets in the solar system.
Neptune experiences violent winds with speeds of up to 750 miles per hour. The atmosphere on Neptune is primarily composed of water, ammonia and methane, and its blue color is partially due to the high amount of methane. Voyager 2 did a close fly-by of Neptune in 1989.