kosmos: Moons of Neptune

Evidence: 82 • authority: 94

Neptune has 16 officially recognized moons. English merchant and astronomer William Lassell discovered the first and largest moon – Triton – on Oct. 10, 1846, just 17 days after a Berlin observatory discovered Neptune. Neptune's first and largest moon – Triton – was discovered just days after the planet was found. We don't know if Lassell had a celebratory beverage after he discovered Triton, but beer helped make the finding possible. Lassell was one of 19th century England's grand amateur astronomers. He used the fortune he made in the brewery business to finance his telescopes.

Evidence: 100 • authority: 72

There are 16 known moons of the planet Neptune, fourteen of which are named after water deities and creatures in Greek mythology. The largest is Triton, discovered by William Lassell on 10 October 1846, 17 days after the discovery of Neptune itself. Over a century passed before the discovery of the second natural satellite, Nereid, in 1949, and another 40 years before Proteus, Neptune's second-largest moon, was discovered in 1989. Triton is unique among moons of planetary mass in that its orbit is retrograde to Neptune's rotation and inclined relative to Neptune's equator, which suggests that it did not form in orbit around Neptune, but was instead gravitationally captured by it. The next-l…

Evidence: 82 • authority: 94

Triton was discovered on Oct. 10, 1846 by British astronomer William Lassell, just 17 days after Neptune itself was discovered. Triton is named after the son of Poseidon (the Greek god comparable to the Roman Neptune). Until the discovery of the second moon Nereid in 1949, Triton was commonly known as simply "the satellite of Neptune." Triton is the largest of Neptune's 13 moons. It is unusual because it is the only large moon in our solar system that orbits in the opposite direction of its planet's rotation―a retrograde orbit.

Evidence: 82 • authority: 94

Triton was discovered on Oct. 10, 1846 by British astronomer William Lassell, just 17 days after Neptune itself was discovered. Triton is named after the son of Poseidon (the Greek god comparable to the Roman Neptune). Until the discovery of the second moon Nereid in 1949, Triton was commonly known as simply "the satellite of Neptune." Triton is the largest of Neptune's 13 moons. It is unusual because it is the only large moon in our solar system that orbits in the opposite direction of its planet's rotation―a retrograde orbit.

Evidence: 60 • authority: 72

Neptune is the eighth and farthest known planet orbiting the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth. Compared to Uranus, its neighbouring ice giant, Neptune is slightly smaller, but more massive and dense. Being composed primarily of gases and liquids, it has no well-defined solid surface. Neptune orbits the Sun once every 164.8 years at an orbital distance of 30.1 astronomical units (4.5 billion kilometres; 2.8 billion miles). It is named after the Roman god of the sea and has the astronomical symbol , representing Neptune's trident. Neptune is not visible to the una…

Evidence: 54 • authority: 72

Neptune has appeared in fiction since shortly after its 1846 discovery, albeit infrequently. It initially made appearances indirectly—through its inhabitants, for example—rather than as a setting. The earliest stories set on Neptune itself portrayed it as a rocky planet rather than as having its actual gaseous composition; later works rectified this error. Extraterrestrial life on Neptune is uncommon in fiction, though the exceptions have ranged from humanoids to gaseous lifeforms. Neptune's largest moon Triton has also appeared in fiction, especially in the late 20th century onwards.

Evidence: 46 • authority: 72

The planet Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observations confirming the existence of a major planet were made on the night of September 23–24, autumnal equinox of 1846, at the Berlin Observatory, by astronomer Johann Gottfried Galle (assisted by Heinrich Louis d'Arrest), working from Le Verrier's calculations. It was a sensational moment of 19th-century science, and dramatic confirmation of Newtonian gravitational theory. In François Arago's apt phrase, Le Verrier had discovered a planet "with the point of his pen". In retrospect, after it was discovered, it turned out it had been observed many times bef…

Evidence: 40 • authority: 72

Triton is the largest natural satellite of the planet Neptune. It is the only moon of Neptune massive enough to be rounded under its own gravity and hosts a thin, hazy atmosphere. Triton orbits Neptune in a retrograde orbit—revolving in the opposite direction to the parent planet's rotation—the only large moon in the Solar System to do so. Triton is thought to have once been a dwarf planet from the Kuiper belt, captured into Neptune's orbit by the latter's gravity. At 2,706.8 kilometers (1,681.9 mi) in diameter, Triton is the seventh-largest moon in the Solar System, the second-largest planetary moon in relation to its primary (after Earth's Moon), and larger than all of the known dwarf pla…

Evidence: 32 • authority: 92

Nereid as a regular satellite of Neptune.. Nereid, Neptune's third largest moon, is considered to be a captured irregular satellite because of its highly eccentric orbit. However, among irregular satellites, Nereid is an outlier: It is the largest, the closest to its host planet, and the most eccentric. We present James Webb Space Telescope near-infrared spectroscopy of Nereid that demonstrates that its composition is inconsistent with its suggested captured origin. We then simulate Nereid's early orbital history subsequent to Triton's capture to demonstrate a plausible dynamical pathway for a regular satellite formed in situ around Neptune to evolve to Nereid's present-day orbit. On the ba…

Evidence: 25 • authority: 88

Neptune Orbital Survey and TRiton Orbiter MissiOn (NOSTROMO): A Mission Concept to Explore the Neptune-Triton System.. IntroductionThe Neptune Orbital Survey and TRitOn MissiOn (NOSTROMO) is a mission concept aimed to explore the ice giant Neptune and its icy moon Triton, with the goal to advance our understanding of ice giant systems and their role in planetary formation both within and beyond our Solar System. Aligned with ESA’s Voyage 2050 plan, NOSTROMO aims to reveal the processes that formed the outer Solar System, provide insights for interpreting the mini-Neptunes exoplanets and enhance our understanding on potential habitable zones beyond Earth. Science ObjectivesThe main goal of t…

Evidence: 24 • authority: 72

The timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. Each object is listed in chronological order of its discovery (multiple dates occur when the moments of imaging, observation, and publication differ), identified through its various designations (including temporary and permanent schemes), and the discoverer(s) listed. Historically the naming of moons did not always match the times of their discovery. Traditionally, the discoverer enjoys the privilege of naming the new object; however, some neglected to do so (E. E. Barnard stated he would "defer any suggestions as to a name" [for Amalthea] "until a…