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Stephen P. Synnott
Stephen P. Synnott (born 1946) is an American astronomer and Voyager scientist at JPL, and expert in spacecraft optical navigation techniques. He has discovered several natural satellites of outer Solar System planets such as Metis, Puck, Larissa (recovered), Cressida, Thebe and Proteus. Honors The minor planet 6154 Stevesynnott, discovered by Henry E. Holt in 1990, was named in his honour. The approved naming citation was published by the Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ... on 1 July 1996 (). References 1946 births American astronomers Planetary scientists Living people {{US-astronomer-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voyager Program
The Voyager program is an American scientific program that employs two robotic interstellar probes, ''Voyager 1'' and ''Voyager 2''. They were launched in 1977 to take advantage of a favorable alignment of Jupiter and Saturn, to Flyby (spaceflight), fly near them while collecting data for transmission back to Earth. After launch the decision was taken to send ''Voyager 2'' near Uranus and Neptune to collect data for transmission back to Earth. As of 2022, the Voyagers are still in operation past the outer boundary of the heliosphere in interstellar space. They collect and transmit useful data to Earth. , ''Voyager 1'' was moving with a velocity of , or 17 km/s, relative to the Sun, and was from the Sun reaching a distance of from Earth as of February 10, 2022. On 25 August 2012, data from ''Voyager 1'' indicated that it had entered interstellar space. , ''Voyager 2'' was moving with a velocity of , or 15 km/s, relative to the Sun, and was from the Sun reaching a distan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Satellite
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons'', a derivation from the Moon of Earth. In the Solar System, there are six planetary satellite systems containing 209 known natural satellites altogether. Seven objects commonly considered dwarf planets by astronomers are also known to have natural satellites: , Pluto, Haumea, , Makemake, , and Eris. , there are 442 other minor planets known to have natural satellites. A planet usually has at least around 10,000 times the mass of any natural satellites that orbit it, with a correspondingly much larger diameter. The Earth–Moon system is a unique exception in the Solar System; at 3,474 kilometres (2,158 miles) across, the Moon is 0.273 times the diameter of Earth and about of its mass. The next largest ratios are the Neptune–Tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outer Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar System" and "solar system" structures in theinaming guidelines document. The name is commonly rendered in lower case ('solar system'), as, for example, in the ''Oxford English Dictionary'' an''Merriam-Webster's 11th Collegiate Dictionary''. is the gravitationally bound system of the Sun and the objects that orbit it. It formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority (99.86%) of the system's mass is in the Sun, with most of the remaining mass contained in the planet Jupiter. The four inner system planets—Mercury, Venus, Earth and Mars—are terrestrial planets, being composed primarily of rock and metal. The four giant planets of the outer system are substant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metis (moon)
Metis , also known as , is the innermost known moon of Jupiter. It was discovered in 1979 in images taken by ''Voyager 1'', and was named in 1983 after the first wife of Zeus, Metis. Additional observations made between early 1996 and September 2003 by the ''Galileo'' spacecraft allowed its surface to be imaged. Metis is tidally locked to Jupiter, and its shape is strongly asymmetrical, with one of the diameters being almost twice as large as the smallest one. It is also one of the two moons known to orbit Jupiter in less than the length of Jupiter's day, the other being Adrastea. It orbits within the main ring of Jupiter, and is thought to be a major contributor of material to the rings. Discovery and observations Metis was discovered in 1979 by Stephen P. Synnott in images taken by the ''Voyager 1'' probe and was provisionally designated as . In 1983, it was officially named after the mythological Metis, a Titaness who was the first wife of Zeus (the Greek equivalen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puck (moon)
Puck is an inner moon of Uranus. It was discovered in December 1985 by the ''Voyager 2'' spacecraft. The name ''Puck'' follows the convention of naming Uranus's moons after characters from Shakespeare. The orbit of Puck lies between the rings of Uranus and the first of Uranus's large moons, Miranda. Puck is approximately spherical in shape and has diameter of about 162 km. It has a dark, heavily cratered surface, which shows spectral signs of water ice. Discovery and naming Puck—the largest inner moon of Uranus—was discovered from the images taken by ''Voyager 2'' on 30 December 1985. It was given the temporary designation S/1985 U 1. The moon was later named after the character Puck who appears in Shakespeare's '' A Midsummer Night's Dream'', a little sprite who travels around the globe at night with the fairies. In Celtic mythology and English folklore, a '' Puck'' is a mischievous sprite, imagined as an evil demon by Christians. It is also designat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larissa (moon)
Larissa, also known as Neptune VII, is the fifth-closest inner satellite of Neptune. It is named after Larissa, a lover of Poseidon (Neptune) in Greek mythology and eponymous nymph of the city in Thessaly, Greece. Discovery It was first discovered by Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky and David J. Tholen, based on fortuitous ground-based stellar occultation observations on May 24, 1981, given the temporary designation S/1981 N 1 and announced on May 29, 1981. The moon was recovered and confirmed to be the only object in its orbit during the ''Voyager 2'' flyby in 1989 after which it received the additional designation S/1989 N 2 on August 2, 1989. The announcement by Stephen P. Synnott spoke of “10 frames taken over 5 days”, which gives a recovery date sometime before July 28. The name was given on September 16, 1991. Characteristics The fourth-largest satellite of Neptune, Larissa is irregular (non-spherical) in shape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cressida (moon)
: ''There is also an asteroid called 548 Kressida.'' Cressida is an inner satellite of Uranus. It was discovered from the images taken by ''Voyager 2'' on 9 January 1986, and was given the temporary designation S/1986 U 3. It was named after Cressida, the Trojan daughter of Calchas, a tragic heroine who appears in William Shakespeare's play ''Troilus and Cressida'' (as well as in tales by Geoffrey Chaucer and others). It is also designated Uranus IX. Cressida belongs to the Portia group of satellites, which includes Bianca, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda and Perdita. These satellites have similar orbits and photometric properties. Other than its orbit, radius of 41 km and geometric albedo of 0.08, virtually nothing is known about it. In the Voyager 2 images Cressida appears as an elongated object, its major axis pointing towards Uranus. The ratio of axes of Cressida's prolate spheroid is 0.8 ± 0.3. Its surface is grey in color. Cres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thebe (moon)
Thebe , also known as , is the fourth of Jupiter's moons by distance from the planet. It was discovered by Stephen P. Synnott in images from the ''Voyager 1'' space probe taken on March 5, 1979, while making its flyby of Jupiter. In 1983, it was officially named after the mythological nymph Thebe. The second largest of the inner satellites of Jupiter, Thebe orbits within the outer edge of the Thebe gossamer ring that is formed from dust ejected from its surface. It is irregularly shaped and reddish in colour, and is thought like Amalthea to consist of porous water ice with unknown amounts of other materials. Its surface features include large craters and high mountains—some of them are comparable to the size of the moon itself. Thebe was photographed in 1979 by the ''Voyager 1'' and ''2'' spacecraft, and later, in more detail, by the ''Galileo'' orbiter in the 1990s. Discovery and observations Thebe was discovered by Stephen P. Synnott in images from the ''Voyager 1'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proteus (moon)
Proteus (), also known as Neptune VIII, is the second-largest Neptunian moon, and Neptune's largest inner satellite. Discovered by ''Voyager 2'' spacecraft in 1989, it is named after Proteus, the shape-changing sea god of Greek mythology. Proteus orbits Neptune in a nearly equatorial orbit at a distance of about 4.75 times the radius of Neptune's equator. Despite being a predominantly icy body more than in diameter, Proteus's shape deviates significantly from an ellipsoid. It is shaped more like an irregular polyhedron with several slightly concave facets and relief as high as . Its surface is dark, neutral in color, and heavily cratered. Proteus's largest crater is Pharos, which is more than in diameter. There are also a number of scarps, grooves, and valleys related to large craters. Proteus is probably not an original body that formed with Neptune. It could have accreted later from the debris formed when the largest Neptunian satellite Triton was captured. Discovery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry E
Henry may refer to: People *Henry (given name) *Henry (surname) * Henry Lau, Canadian singer and musician who performs under the mononym Henry Royalty * Portuguese royalty ** King-Cardinal Henry, King of Portugal ** Henry, Count of Portugal, Henry of Burgundy, Count of Portugal (father of Portugal's first king) ** Prince Henry the Navigator, Infante of Portugal ** Infante Henrique, Duke of Coimbra (born 1949), the sixth in line to Portuguese throne * King of Germany ** Henry the Fowler (876–936), first king of Germany * King of Scots (in name, at least) ** Henry Stuart, Lord Darnley (1545/6–1567), consort of Mary, queen of Scots ** Henry Benedict Stuart, the 'Cardinal Duke of York', brother of Bonnie Prince Charlie, who was hailed by Jacobites as Henry IX * Four kings of Castile: **Henry I of Castile **Henry II of Castile **Henry III of Castile **Henry IV of Castile * Five kings of France, spelt ''Henri'' in Modern French since the Renaissance to italianize the name an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function The Minor Planet Center is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids), calculating their orbits and publishing this information via the '' Minor Planet Circulars''. Under the auspices of the International Astronomical Union (IAU), it operates at the Smithsonian Astrophysical Observatory, which is part of the Center for Astrophysics along with the Harvard College Observatory. The MPC runs a number of free online services for observers to assist them in observing minor planets and comets. The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to astrometric data, the MPC collect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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