NationMaster - Encyclopedia: Proteus (moon)

Proteus (proe'-tee-us, Greek Πρωτέας) is one of Neptune's moons. It is named after Proteus, the shape-changing sea god in Greek mythology. It is also designated Neptune VIII. Download high resolution version (727x726, 31 KB)Photo of Netptunes satellite Proteus taken by Voyager 2 (large version). ... The Voyager 2 spacecraft was launched in 1977. ... Stephen P. Synnott is a Voyager scientist who discovered several moons of Jupiter, Saturn, Uranus, and Neptune. ... June 16 is the 167th day of the year in the Gregorian calendar (168th in leap years), with 198 days remaining. ... 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolas. ... A kilometre (American spelling: kilometer), symbol: km is a unit of length in the metric system equal to 1000 metres (from the Greek words Ï‡Î¯Î»Î¹Î± (khilia) = thousand and Î¼ÎÏ„ÏÎ¿ (metro) = count/measure). ... The astronomical unit (AU or au or a. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... A kilometre (American spelling: kilometer) (symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... A kilometre (American spelling: kilometer) (symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... A day (symbol: d) is a unit of time equal to 24 hours. ... The circumference is the distance around a closed curve. ... A kilometre (American spelling: kilometer) (symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ... This article is about velocity in physics. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... The Laplace plane is defined as the mean plane occupied by the orbit of a satellite during a precession cycle. ... Moons of solar system scaled to Earths Moon The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... Atmospheric characteristics Surface pressure â‰«100 MPa Hydrogen - H2 80% Â±3. ... For the geometric term, see diameter. ... Area is a physical quantity expressing the size of a part of a surface. ... Square kilometre (US spelling: Square kilometer), symbol km², is an SI unit of surface area. ... Volume, also called capacity, is a quantification of how much space an object occupies. ... A cubic kilometre (symbol km³) is an SI derived unit of volume. ... Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... Density (symbol: Ï - Greek: rho) is a measure of mass per unit of volume. ... ... Acceleration is the time rate of change of velocity, and at any point on a v-t graph, it is given by the gradient of the tangent to that point In physics, acceleration (symbol: a) is defined as the rate of change (or time derivative) of velocity. ... In physics, for a given gravitational field and a given position, the escape velocity is the minimum speed an object without propulsion, at that position, needs to have to move away indefinitely from the source of the field, as opposed to falling back or staying in an orbit within a... On a prograde planet like the Earth, the sidereal day is shorter than the solar day. ... Axial tilt is an astronomical term regarding the inclination angle of a planets rotational axis in relation to its orbital plane. ... The albedo is a measure of reflectivity of a surface or body. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... The pascal (symbol Pa) is the SI unit of pressure. ... Atmospheric characteristics Surface pressure â‰«100 MPa Hydrogen - H2 80% Â±3. ... Moons of solar system scaled to Earths Moon The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... In Greek mythology, Proteus is an early sea-god, one of several deities whom Homer calls the Old Man of the Sea, whose name suggests the first, as protogonos is the firstborn. No mention is made of his parents, until for later mythographers he became the son of Poseidon in... Greek mythology comprises the collected narratives of Greek gods, goddesses, heroes, and heroines, originally created and spread within an oral-poetic tradition. ...

Discovery

Proteus was discovered from the images taken by Voyager 2 probe during the Neptune flyby in 1989. It received the temporary designation S/1989 N 1. Stephen P. Synnott and Bradford A. Smith announced (IAUC 4806) its discovery on July 7, 1989, speaking only of “17 frames taken over 21 days”, which gives a discovery date of sometime before June 16. The Voyager 2 spacecraft was launched in 1977. ... 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... Stephen P. Synnott is a Voyager scientist who discovered several moons of Jupiter, Saturn, Uranus, and Neptune. ... July 7 is the 188th day of the year (189th in leap years) in the Gregorian Calendar, with 177 days remaining. ... 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... June 16 is the 167th day of the year in the Gregorian calendar (168th in leap years), with 198 days remaining. ...

Physical characteristics

Proteus is more than 400 kilometres in diameter, larger than Nereid, another moon of Neptune. However, it was not discovered by Earth-based telescopes because it is so close to the planet that it is lost in the glare of reflected sunlight. Proteus is one of the darkest objects in the solar system, as dark as soot; like Saturn's moon Phoebe, it reflects only 6 percent of the sunlight that strikes it. Proteus is very cratered showing no sign of any geological modification. It is also irregularly shaped; scientists believe Proteus is about as large as a body of its density can be without being pulled into a spherical shape by its own gravity. Saturn's moon Mimas has much more regular shape despite being less massive than Proteus. Voyager 2 view of Nereid. ... Earth, also known as Terra, and Tellus mostly in the 19th century, is the third-closest planet to the Sun. ... Presentation of the solar system (not to scale) The solar system comprises our Sun and the retinue of celestial objects gravitationally bound to it. ... Soot, also called lampblack, Pigment Black 7, or carbon black, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smokeâ€”especially from the combustion of carbon-rich organic fuels in the lack of... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... For other meanings see Phoebe. ... This article is about impact craters, also known as meteor craters. ... ... Mimas (mye-mus) is a moon of Saturn that was discovered in 1789 by William Herschel. ...

Image File history File links Download high resolution version (1280x1005, 60 KB)A simulated view of Proteus orbiting Neptune. ... Image File history File links Download high resolution version (1280x1005, 60 KB)A simulated view of Proteus orbiting Neptune. ... A computer simulation or a computer model is a computer program which attempts to simulate an abstract model of a particular system. ... Atmospheric characteristics Surface pressure â‰«100 MPa Hydrogen - H2 80% Â±3. ...

Contents

Discovery

Physical characteristics

See also

External links