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.
Evidence of early planetary shake-up
on September 10, 2018 at 3:12 pm
Scientists have studied an unusual pair of asteroids and discovered that their existence points to an early planetary rearrangement in our solar system. […]
New exoplanet found very close to its star
on September 5, 2018 at 8:19 pm
Using data from NASA's Kepler Space Telescope, an international team has discovered a new exoplanet twice the size of Earth. It orbits its star every six days and is thus very close to it, about 10 times closer than Mercury is to the Sun. […]
Collective gravity, not Planet Nine, may explain...
on June 4, 2018 at 5:17 pm
Bumper car-like interactions at the edges of our solar system -- and not a mysterious ninth planet -- may explain the dynamics of strange bodies called 'detached objects,' according to a new study. […]
From car engines to exoplanets
on April 4, 2018 at 3:47 pm
Chemical models developed to help limit the emission of pollutants by car engines are being used to study the atmospheres of hot exoplanets orbiting close to their stars. […]
Hubble sees Neptune's mysterious shrinking storm
on February 15, 2018 at 6:11 pm
Three billion miles away on the farthest known major planet in our solar system, an ominous, dark storm -- once big enough to stretch across the Atlantic Ocean from Boston to Portugal -- is shrinking out of existence as seen in pictures of Neptune taken by NASA's Hubble Space Telescope. […]
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Dwarf companion to EPIC 206011496 detected by...
on September 20, 2018 at 1:00 pm
Using ESO's Very Large Telescope (VLT), European astronomers have uncovered the presence of an M-dwarf around the star EPIC 206011496. The newly found object is more than 60 percent less massive than our sun and is bounded to the primary star. The finding is reported in a paper published September 10 on arXiv.org. […]
Scientists find evidence for early planetary...
on September 10, 2018 at 4:51 pm
Scientists at Southwest Research Institute studied an unusual pair of asteroids and discovered that their existence points to an early planetary rearrangement in our solar system. […]
New research suggest Pluto should be reclassified...
on September 7, 2018 at 3:12 pm
The reason Pluto lost its planet status is not valid, according to new research from the University of Central Florida in Orlando. […]
A new exoplanet is discovered by an international...
on September 5, 2018 at 7:48 pm
Wolf 503b, an exoplanet twice the size of Earth, has been discovered by an international team of Canadian, American and German researchers using data from NASA's Kepler Space Telescope. The find is described in a new study whose lead author is Merrin Peterson, an Institute for research on exoplanets (iREx) graduate student who started her master's degree at Université de Montréal (UdeM) in May. […]
How a NASA scientist looks in the depths of the...
on August 29, 2018 at 7:38 pm
For centuries, scientists have worked to understand the makeup of Jupiter. It's no wonder: this mysterious planet is the biggest one in our solar system by far, and chemically, the closest relative to the Sun. Understanding Jupiter is a key to learning more about how our solar system formed, and even about how other solar systems develop. […]