Planet Neptune: Facts About Its Orbit, Moons & Rings

Neptune is the eighth planet from the sun in our solar system. This blue gas giant is far larger than Earth, at more than 17 times Earth’s mass and nearly 58 times Earth’s volume, according to NASA. Neptune’s rocky core is surrounded by a slushy fluid mix of water, ammonia and methane ice. 

Astronomer Galileo Galilei was one of the first people to identify Neptune as a space object, however he assumed it was a star based on its slow movement. Around two hundred years later, in 1846, French astronomer Urbain Jean Joseph Le Verrier calculated the approximate location of Neptune by studying gravity-induced disturbances in the motions of Uranus, according to a synopsis written by researchers at the University of St. Andrews in Scotland