Neptune is the eighth largest planet in our solar system. It is the fourth-largest planet in diameter and the third-largest planet of all the planets in the solar system. Neptune is 17 times the mass of the Earth, slightly higher than its nearest planet Uranus. Neptune is denser and smaller than Uranus, as its greater mass causes more gravitational compression of its atmosphere.
Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 AU (4.5 billion km). It is named after the Roman god of the sea and has the celestial symbol ♆, a stylish version of the trident of the Roman god Neptune.
Neptune is not visible from the eye by the Earth and is the only planet in the solar system that has been found by mathematical prediction rather than empirical observation. Uranus’ unexpected change in its orbit prompted Alexis Bouvard that its orbit was subject to gravitational disturbances by an unknown planet.
Neptune was later spotted with a telescope on 23 September 1846. Within a fraction of the position predicted by Johann Gale to Urbain le Verrier. It soon discovered the largest moon, Triton.
However none of the remaining 13 moons of the planet were seen with binoculars until the 20th century. The planet’s distance from Earth gives it a very small size, making it challenging to study with Earth-based telescopes. Neptune was visited by Voyager 2 when he flew near the planet on 25 August 1989. The advent of the Hubble Space Telescope and large ground-based telescopes with adaptive optics have recently allowed for additional detailed observations from afar.
Like Jupiter and Saturn, Neptune’s atmosphere is composed primarily of hydrogen and helium, as well as traces of hydrocarbons and possibly nitrogen, although it has a higher proportion of “ions” such as water, ammonia, and methane. However, similar to Uranus, its interior is mainly composed of ions and rock. Uranus and Neptune are generally considered “ice giants” to emphasize this difference. Traces of methane in the outer regions for the appearance of the planet’s blue color.
Unlike the misty, relatively featureless environment of Uranus, Neptune (Neptune) environments have active and visible weather patterns. For example, at the time of the Vyzer 2 flyby in 1989, the planet had a Great Dark Spot compared to the Great Red Spot on Jupiter in the southern hemisphere. These weather patterns are driven by the strongest sustained winds of any planet in the solar system, with wind speeds exceeding 2,100 km / h (580 m / s, 1,300 mph). Due to its great distance from the Sun, Neptune’s outer atmosphere is one of the coldest places in the Solar System, with temperatures reaching 55 K (−218 ° C; −361 ° F) topped. The temperature at the center of the planet is about 5,400 K (5,100 ° C; 9,300 ° F). Neptune has a faint and fragmented ring system (labeled “arcs”), which was discovered in 1984, then later confirmed by Voyager 2.