Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid
These are organized by a classification scheme developed exclusively for Cosma. More…
Neptune : the planet eighth in order from the sun — Webster
Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.50×109 km). It is named after the Roman god of the sea and has the astronomical symbol ♆, a stylised version of the god Neptune’s trident.
Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus led Alexis Bouvard to deduce that its orbit was subject to gravitational perturbation by an unknown planet. Neptune was subsequently observed with a telescope on 23 September 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier. Its largest moon, Triton, was discovered shortly thereafter, though none of the planet’s remaining known 14 moons were located telescopically until the 20th century. The planet’s distance from Earth gives it a very small apparent size, making it challenging to study with Earth-based telescopes. Neptune was visited by Voyager 2, when it flew by the planet on 25 August 1989. The advent of the Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.
Neptune’s composition can be compared and contrasted with the Solar System’s other giant planets. Like Jupiter and Saturn, Neptune’s atmosphere is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, but it contains a higher proportion of “ices” such as water, ammonia, and methane. However, its interior, like that of Uranus, is primarily composed of ices and rock, which is why Uranus and Neptune are normally considered “ice giants” to emphasise this distinction. Traces of methane in the outermost regions in part account for the planet’s blue appearance.
In contrast to the hazy, relatively featureless atmosphere of Uranus, Neptune’s atmosphere has active and visible weather patterns. For example, at the time of the Voyager 2 flyby in 1989, the planet’s southern hemisphere had a Great Dark Spot comparable to the Great Red Spot on Jupiter. These weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 kilometres per hour (580 m/s; 1,300 mph). Because of its great distance from the Sun, Neptune’s outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching 55 K (−218 °C). Temperatures at the planet’s center are approximately 5,400 K (5,100 °C). Neptune has a faint and fragmented ring system (labelled “arcs”), which was first detected during the 1960s and confirmed by Voyager 2. — Wikipedia
Neptune News -- ScienceDaily Planet Neptune News. Read astronomy articles on Neptune's oddball moon Triton. See images of Neptune and more.
Examining ice giants of our solar system
on February 28, 2020 at 7:20 pm
NASA's James Webb Space Telescope will unlock secrets of the atmospheres of Uranus and Neptune.
Large exoplanet could have the right conditions...
on February 27, 2020 at 2:20 am
Astronomers have found an exoplanet more than twice the size of Earth to be potentially habitable, opening the search for life to planets significantly larger than Earth but smaller than Neptune.
'Cold Neptune' and two temperate super-Earths...
on January 14, 2020 at 2:09 pm
A 'cold Neptune' and two potentially habitable worlds are part of a cache of five newly discovered exoplanets and eight exoplanet candidates found orbiting nearby red dwarf stars. The two potentially habitable planets are among the nearest stars to our own Sun, making them prime targets for observations by next-generation space- and land-based telescopes.
Hidden giant planet revealed around tiny white...
on December 4, 2019 at 7:58 pm
The first evidence of a giant planet orbiting a dead white dwarf star has been found in the form of a disc of gas formed from its evaporating atmosphere.
NASA finds Neptune moons locked in 'dance of...
on November 14, 2019 at 7:00 pm
Even by the wild standards of the outer solar system, the strange orbits that carry Neptune's two innermost moons are unprecedented, according to newly published research.
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A mirror image of Earth and sun
on June 4, 2020 at 1:19 pm
Among the more than 4,000 known exoplanets, KOI-456.04 is something special: less than twice the size of Earth, it orbits a sun-like star. And it does so with a star-planet distance that could permit planetary surface temperatures conducive to life. The object was discovered by a team led by the Max Planck Institute for Solar System Research in Göttingen. Its host star, called Kepler-160, actually emits visible light; the central stars of almost all other exoplanets, on the other hand, […]
How Europe's CHEOPS satellite will improve the...
on May 28, 2020 at 11:21 am
While the planet has been on lockdown the last two months, a new space telescope called CHEOPS opened its eyes, took its first pictures of the heavens and is now open for business.
Why astronomers now doubt there is an...
on May 26, 2020 at 11:53 am
Planet Nine is a theoretical, undiscovered giant planet in the mysterious far reaches of our solar system.
Researchers observe protons 'playing hopscotch'...
on May 25, 2020 at 1:53 pm
An international team of researchers from University College Dublin (UCD) and University of Saskatchewan, Canada, have observed 'proton-hopping' movement in a high-pressure form of ice (Ice VII lattices).
Could theorized Planet 9 be a primordial black...
on May 25, 2020 at 1:26 pm
There are eight classical planets in our solar system, from speedy Mercury to distant Neptune. There are also numerous dwarf planets, such as Pluto and Ceres. While we continue to find more dwarf planets, there are some hints that another large planet could lurk far beyond Neptune. This Planet Nine is thought to be a "super-Earth," about five times the mass of our planet, which would make it about twice as large as Earth. But despite several searches for the planet, it has not yet been found.