The planet Neptune, the fourth largest planet in the solar system, boasts the fastest winds among the eight planets as well as a massive storm system that appears as a giant dark spot. Its far-flung position in the outer solar system makes it difficult to observe from Earth, and much of what is known today about the blue Jovian world is due to the flyby of the Voyager 2 spacecraft.
Discovery of Neptune
The mathematician Alexis Bouvard published a series of papers that plotted the orbit of Uranus In 1846. Two astronomers, John Couch Adams from the United Kingdom and Urbain Le Verrier from France, examined the data and concluded that another planet was influencing the orbit of Uranus. They also predicted the position of the unknown planet.
The astronomer Johann Gottfried Galle used the Berlin observatory to find the predicted planet, which was named Neptune after the Roman god of the oceans. The discovery led to an international dispute over the discovery. Today, both Adams and Le Verrier are credited with the discovery of Neptune.
Thirteen moons, all of which are composed of rock and ice, revolve around Neptune. William Lassell discovered Triton, Neptune’s largest moon, just 17 days after the discovery of Neptune itself. Triton is the only moon in the solar system that orbits in an opposite direction to the planet’s spin.
The Voyager 2 spacecraft discovered Proteus, the second largest moon of Neptune, in 1989. It takes a highly irregular in shape and is one of the darkest objects in the solar system. Gerard P. Kuiper discovered the third largest moon, Nereid, in 1949. Its highly elliptical orbit suggests it may have been an asteroid captured from the outer solar system.
Incomplete rings were first observed around Neptune in the mid-1980s, but conclusive evidence did not occur until the Voyager 2 spacecraft imaged them directly in 1989. The main rings around Neptune are named Galle, Le Verrier, Lassell, Arago and Adams, after the astronomers who made important discoveries related to Neptune.
The rings are thought to have formed from the destruction of a moon that once orbited Neptune. Composed mainly of dust and rock, Neptune’s rings are far darker than the rings of Saturn, which are made of ice.
Neptune’s atmosphere consists mainly of gases such as hydrogen and helium, making it a gas giant. Other components of the atmosphere include water, methane and ammonia. The presence of methane in the upper atmosphere leads to its characteristic bright blue color.
The atmosphere of Neptune is thought to harbor the fastest winds in the solar system, moving at the supersonic speed of 2,400 kilometers per hour (1,500 miles per hour). The planet has huge anticyclonic storms the size of Earth, lasting for years on end. These are collectively known as the great dark spots.