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.
- Data reveals evidence of molecular absorption in...on October 26, 2020 at 3:42 pm
An international team of scientists recently measured the spectrum of the atmosphere of a rare hot Neptune exoplanet, whose discovery by NASA's Transiting Exoplanet Survey Satellite (TESS) was announced just last month.
- New study details atmosphere on 'hot Neptune' 260...on October 23, 2020 at 4:31 pm
Astronomers have crunched data from NASA's TESS and Spitzer space telescopes to portray for the first time the atmosphere of a highly unusual kind of exoplanet dubbed a 'hot Neptune.'
- Surprisingly dense exoplanet challenges planet...on August 4, 2020 at 4:22 pm
New detailed observations reveal a young exoplanet, orbiting a young star in the Hyades cluster, that is unusually dense for its size and age. Weighing in at 25 Earth-masses, and slightly smaller than Neptune, this exoplanet's existence is at odds with the predictions of leading planet formation theories.
- First exposed planetary core discovered allows...on July 1, 2020 at 4:54 pm
The surviving core of a gas giant has been discovered orbiting a distant star, offering an unprecedented glimpse into the interior of a planet.
- Orb hidden in distant dust is 'infant'...on June 24, 2020 at 4:04 pm
The discovery could help astronomers understand how planets like Earth form and evolve.
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
- Exoplanet survey spacecraft discovers two new...on November 9, 2020 at 2:00 pm
Using NASA's Transiting Exoplanet Survey Satellite (TESS), astronomers have detected two new warm alien worlds orbiting inactive M dwarfs. The newfound exoplanets, designated TOI 122b and TOI 237b, are about 2.7 and 1.4 times larger than the Earth, respectively, and warmer than our home planet. The finding is reported in a paper published October 29 on the arXiv pre-print server.
- NASA contacts Voyager 2 using upgraded Deep Space...on November 4, 2020 at 1:04 pm
On Oct. 29, mission operators sent a series of commands to NASA's Voyager 2 spacecraft for the first time since mid-March. The spacecraft has been flying solo while the 70-meter-wide (230-foot-wide) radio antenna used to talk to it has been offline for repairs and upgrades. Voyager 2 returned a signal confirming it had received the "call" and executed the commands without issue.
- Lighting a path to Planet Nineon October 30, 2020 at 12:51 pm
The search for Planet Nine—a hypothesized ninth planet in our solar system—may come down to pinpointing the faintest orbital trails in an incredibly dark corner of space.
- Where were Jupiter and Saturn born?on October 29, 2020 at 4:51 pm
New work led by Carnegie's Matt Clement reveals the likely original locations of Saturn and Jupiter. These findings refine our understanding of the forces that determined our Solar System's unusual architecture, including the ejection of an additional planet between Saturn and Uranus, ensuring that only small, rocky planets, like Earth, formed inward of Jupiter.
- NASA's Webb to examine objects in the graveyard...on October 29, 2020 at 2:04 pm
Beyond the orbit of Neptune, a diverse collection of thousands of dwarf planets and other relatively small objects dwells in a region called the Kuiper Belt. These often-pristine leftovers from our solar system's days of planet formation are called Kuiper Belt objects, or trans-Neptunian objects. NASA's upcoming James Webb Space Telescope will examine an assortment of these icy bodies in a series of programs called Guaranteed Time Observations shortly after its launch in 2021. The goal is to […]