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.
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.
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.
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Uranian moons in new light
on September 14, 2020 at 1:50 pm
More than 230 years ago astronomer William Herschel discovered the planet Uranus and two of its moons. Using the Herschel Space Observatory, a group of astronomers led by Örs H. Detre of the Max Planck Institute for Astronomy now has succeeded in determining physical properties of the five main moons of Uranus. The measured infrared radiation, which is generated by the Sun heating their surfaces, suggests that these moons resemble dwarf planets like Pluto. The team developed a new analysis […]
Finding magnetic eruptions in space with an AI...
on September 2, 2020 at 11:46 am
An alert pops up in your email: The latest spacecraft observations are ready. You now have 24 hours to scour 84 hours-worth of data, selecting the most promising split-second moments you can find. The data points you choose, depending on how you rank them, will download from the spacecraft in the highest possible resolution; researchers may spend months analyzing them. Everything else will be overwritten like it was never collected at all.
50 new planets confirmed in machine learning first
on August 25, 2020 at 1:08 pm
Fifty potential planets have been confirmed by a new machine learning algorithm developed by University of Warwick scientists.
Could Planet 9 be a primordial black hole?
on August 24, 2020 at 1:40 pm
For several years, astronomers and cosmologists have theorized about the existence of an additional planet with a mass 10 times greater than that of Earth, situated in the outermost regions of the solar system. This hypothetical planet, dubbed Planet 9, could be the source of gravitational effects that would explain the unusual patterns in the orbits of trans-Neptunian objects (TNOs) highlighted by existing cosmological data. TNOs are celestial bodies that orbit the sun and are located beyond […]
NASA's planet Hunter completes its primary mission
on August 11, 2020 at 4:37 pm
On July 4, NASA's Transiting Exoplanet Survey Satellite (TESS) finished its primary mission, imaging about 75% of the starry sky as part of a two-year-long survey. In capturing this giant mosaic, TESS has found 66 new exoplanets, or worlds beyond our solar system, as well as nearly 2,100 candidates astronomers are working to confirm.