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Skathi (moon)
Skathi , also named Saturn XXVII and originally spelled Skadi, is a natural satellite of the planet Saturn. Skathi is one of Saturn's irregular moons, in its Norse group of satellites. It was discovered on September 23, 2000, by a team of astronomers led by Brett Gladman. The team announced their discovery on December 7, 2000, along with seven other satellites of Saturn, namely; Tarvos, Ijiraq, Thrymr, Siarnaq, Mundilfari, Erriapus, and Suttungr. The moon was named after Skaði, a figure in Norse mythology, as part of an effort to diversify the largely Greek and Roman names of astronomical objects. Skathi takes just over 725 days to complete an orbit of Saturn and it is estimated to take hours to rotate on its axis. It orbits at a greater distance from Saturn than many of the planet's other satellites, with a large orbital inclination and eccentricity, and it moves in a retrograde direction. Not much is known about Skathi, because it is a dim object. Other than Earth-bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada–France–Hawaii Telescope
The Canada–France–Hawaii Telescope (CFHT) is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters (13,793 feet), part of the Mauna Kea Observatory. Operational since 1979, the telescope is a Prime Focus/ Cassegrain configuration with a usable aperture diameter of . CFHT currently planning a refurbishment to the facility in the 2020s. The facility will be reconstructed with a new 11-m telescope to produce the Maunakea Spectroscopic Explorer, retaining the same base building and infrastructure. First light is expected in 2029. Funding The corporation is bound by a tripartite agreement between the University of Hawaii at Manoa, in the United States, the National Research Council (NRC) in Canada and the Centre National de la Recherche Scientifique (CNRS) in France. CFHT also has partnerships with the National Astronomical Observatory of China (NAOC), the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taiwan, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ijiraq (moon)
Ijiraq, or Saturn XXII (22), is a small prograde irregular satellite of Saturn. It was discovered by the team of Brett Gladman, John J. Kavelaars, ''et al.'' in 2000, and given the temporary designation . December 19, 2000 (discovery and ephemeris) It was named in 2003 after the ijiraq, a creature in . [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassini–Huygens
''Cassini–Huygens'' ( ), commonly called ''Cassini'', was a space research, space-research mission by NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a space probe to study the planet Saturn and its system, including its Rings of Saturn, rings and Moons of Saturn, natural satellites. The Large Strategic Science Missions, Flagship-class robotic spacecraft comprised both NASA's ''Cassini'' space probe and ESA's Huygens (spacecraft), ''Huygens'' lander (spacecraft), lander, which landed on Saturn's largest moon, Titan (moon), Titan. ''Cassini'' was the fourth space probe to visit Saturn and the first to enter its orbit, where it stayed from 2004 to 2017. The two craft took their names from the astronomers Giovanni Domenico Cassini, Giovanni Cassini and Christiaan Huygens. Launched aboard a Titan IV, Titan IVB/Centaur on October 15, 1997, ''Cassini'' was active in space for nearly 20 years, with 13 years spent orbiting Saturn and studying the pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retrograde Motion
Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object (right figure). It may also describe other motions such as precession or nutation of an object's rotational axis. Prograde or direct motion is more normal motion in the same direction as the primary rotates. However, "retrograde" and "prograde" can also refer to an object other than the primary if so described. The direction of rotation is determined by an inertial frame of reference, such as distant fixed stars. In the Solar System, the orbits around the Sun of all planets and most other objects, except many comets, are prograde. They orbit around the Sun in the same direction as the sun rotates about its axis, which is counterclockwise when observed from above the Sun's north pole. Except for Venus and Uranus, planetary rotations around their axes are also prograde. Most natural satellites have prograde or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eccentricity (orbit)
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values between 0 and 1 form an elliptic orbit, 1 is a parabolic escape orbit (or capture orbit), and greater than 1 is a hyperbola. The term derives its name from the parameters of conic sections, as every Kepler orbit is a conic section. It is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the Galaxy. Definition In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit. The eccentricity of this Kepler orbit is a non-negative number that defines its shape. The eccentricity may take the following values: * circular orbit: ''e'' = 0 * elliptic orbit: 0 < ''e'' < 1 * [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator. For pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion. For most situations, orbital motion is adequately approximated by Newtonian mechanics, which explains gravity as a force obeying an inverse-square law. However, Albert Einstein's general theory of relativity, which accounts for gravity as due to curvature of spacetime, with orbits following geodesics, provides a more accurate calculation and understanding of the exact mechanics of orbi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation Around A Fixed Axis
Rotation around a fixed axis is a special case of rotational motion. The fixed-axis hypothesis excludes the possibility of an axis changing its orientation and cannot describe such phenomena as wobbling or precession. According to Euler's rotation theorem, simultaneous rotation along a number of stationary axes at the same time is impossible; if two rotations are forced at the same time, a new axis of rotation will appear. This article assumes that the rotation is also stable, such that no torque is required to keep it going. The kinematics and dynamics of rotation around a fixed axis of a rigid body are mathematically much simpler than those for free rotation of a rigid body; they are entirely analogous to those of linear motion along a single fixed direction, which is not true for ''free rotation of a rigid body''. The expressions for the kinetic energy of the object, and for the forces on the parts of the object, are also simpler for rotation around a fixed axis, than for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Objects
An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists in the observable universe. In astronomy, the terms ''object'' and ''body'' are often used interchangeably. However, an astronomical body or celestial body is a single, tightly bound, contiguous entity, while an astronomical or celestial ''object'' is a complex, less cohesively bound structure, which may consist of multiple bodies or even other objects with substructures. Examples of astronomical objects include planetary systems, star clusters, nebulae, and galaxies, while asteroids, moons, planets, and stars are astronomical bodies. A comet may be identified as both body and object: It is a ''body'' when referring to the frozen nucleus of ice and dust, and an ''object'' when describing the entire comet with its diffuse coma and tail. History Astronomical objects such as stars, planets, nebulae, asteroids and comets have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norse Mythology
Norse, Nordic, or Scandinavian mythology is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia, and into the Nordic folklore of the modern period. The northernmost extension of Germanic mythology and stemming from Proto-Germanic folklore, Norse mythology consists of tales of various deities, beings, and heroes derived from numerous sources from both before and after the pagan period, including medieval manuscripts, archaeological representations, and folk tradition. The source texts mention numerous gods such as the thunder-god Thor, the raven-flanked god Odin, the goddess Freyja, and numerous other deities. Most of the surviving mythology centers on the plights of the gods and their interaction with several other beings, such as humanity and the jötnar, beings who may be friends, lovers, foes, or family members of the gods. The cosmos in Norse mythology consists of Nine Worl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suttungr (moon)
Suttungr , or Saturn XXIII, is a natural satellite of Saturn. It was discovered by Brett J. Gladman, et al. in 2000, and given the temporary designation S/2000 S 12. It was named for Suttungr in Norse mythology, a Jötunn or giant who once owned the mead of poetry. Suttungr is about 7 kilometres in diameter, and orbits Saturn at an average distance of 19,667 Mm in 1029.703 days. It may have formed from debris knocked off Phoebe. The Suttung orbit is retrograde, at an inclination of 174° to the ecliptic (151° to Saturn's equator) and with an eccentricity of 0.131. Its rotation period is hours, and like Albiorix its light curve exhibits two minima at certain angles, and three minima at others. Having a similar gray color and orbit as Thrymr, the two moons may be members of the same dynamical family. Its name was announced in its oblique form Suttung iIAU Circular 8177 However, the IAU Working Group on Planetary System Nomenclature later decided to add the no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erriapus
Erriapus , or Saturn XXVIII (28), is a prograde irregular satellite of Saturn. It was discovered by Brett Gladman, John J. Kavelaars and colleagues in 2000, and given the temporary designation S/2000 S 10. It was named Erriapo in August 2003 after ''Erriapus'' (also rendered ''Erriappus''), a giant in Gaulish mythology; the name was changed from dative ''Erriapo'' to nominative ''Erriapus'' per IAU conventions in late 2007. With a rotation period of and an elongated shape, it is a candidate for a contact binary In astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes. A binary system whose stars share an envelope may also be called an overcontac ... or binary moon. References *Ephemerifrom IAU-MPC NSES External links {{DEFAULTSORT:Erriapus (Moon) Gallic group Moons of Saturn Irregular satellites Astronomical objects discovered in 2000 Moons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
