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Pan (moon)
Pan is the innermost named Natural satellite, moon of Saturn. It is a small, walnut-shaped moon approximately 35 kilometres across and 23 km wide that orbits within the Encke Gap in Saturn's A Ring. Pan is a Shepherd moon, ring shepherd and is responsible for keeping the Encke Gap free of ring particles. It is sometimes described as having the appearance of a ravioli. It was discovered by Mark R. Showalter in 1990 from analysis of old ''Voyager 2'' probe photos and received the provisional designation because the discovery images dated back to 1981.IAUC 5052: ''Saturn'' July 16, 1990 (discovery) Prediction and discovery The existence of a moon in the Encke Gap was first predicted by Jeffrey N. Cuzzi and Jeffrey D. Scargle in 1985, based on wavy edges of the gap which indicated a gravitatio ...[...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] |
Moons Of Saturn
The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to enormous Titan (moon), Titan, which is larger than the planet Mercury (planet), Mercury. Saturn has 83 natural satellite, moons with confirmed orbits that are not embedded in its Rings of Saturn, rings—of which only 13 have diameters greater than 50 kilometers—as well as dense rings that contain millions of embedded moonlets and innumerable smaller ring particles. Seven Saturnian moons are large enough to have collapsed into a relaxed, ellipsoidal shape, though only one or two of those, Titan and possibly Rhea (moon), Rhea, are currently in hydrostatic equilibrium. Particularly notable among Saturn's moons are Titan, the second-List of natural satellites, largest moon in the Solar System (after Jupiter's Ganymede (moon), Ganymede), with a Atmosphere of Titan#Composition, nitrogen-rich Earth-like Atmosphere of Titan, atmosphere and a landscape featuring dry river networks and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Natural Satellites
The Solar System's planets, and its most likely dwarf planets, are known to be orbited by at least 221 natural satellites, or moons. At least 20 of them are large enough to be gravitationally rounded; of these, all are covered by a crust of ice except for Earth's Moon and Jupiter's Io. Several of the largest ones are in hydrostatic equilibrium and would therefore be considered dwarf planets or planets if they were in direct orbit around the Sun and not in their current states (orbiting planets or dwarf planets). Moons are classed in two separate categories according to their orbits: regular moons, which have prograde orbits (they orbit in the direction of their planets' rotation) and lie close to the plane of their equators, and irregular moons, whose orbits can be pro- or retrograde (against the direction of their planets' rotation) and often lie at extreme angles to their planets' equators. Irregular moons are probably minor planets that have been captured from surround ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prometheus (moon)
Prometheus is an inner satellite of Saturn. It was discovered in 1980 (on October 24) from photos taken by the ''Voyager 1'' probe, and was provisionally designated . In late 1985 it was officially named after Prometheus, a Titan in Greek mythology. It is also designated . Prometheus is extremely elongated, measuring approximately . It has several ridges and valleys and a number of impact craters of about diameter are visible, but it is less cratered than nearby Pandora, Epimetheus, and Janus. From its very low density and relatively high albedo, it is likely that Prometheus is a very porous icy body. There is much uncertainty in these values, however, and so this remains to be confirmed. Interactions with F Ring and other moons Prometheus is a shepherd satellite for the inner edge of Saturn's narrow F Ring. Pandora orbits just outside the F Ring, and has traditionally been viewed as an outer shepherd of the ring; however, recent studies indicate that only Prometheus con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
F Ring
The rings of Saturn are the most extensive ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometers to meters, that orbit around Saturn. The ring particles are made almost entirely of water ice, with a trace component of rocky material. There is still no consensus as to their mechanism of formation. Although theoretical models indicated that the rings were likely to have formed early in the Solar System's history, newer data from '' Cassini'' suggested they formed relatively late. Although reflection from the rings increases Saturn's brightness, they are not visible from Earth with unaided vision. In 1610, the year after Galileo Galilei turned a telescope to the sky, he became the first person to observe Saturn's rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens was the first person to describe them as a disk surrounding Saturn. The concept that Saturn's rin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseshoe Orbit
In celestial mechanics, a horseshoe orbit is a type of co-orbital configuration, co-orbital motion of a small orbiting body relative to a larger orbiting body. The osculating orbit, osculating (instantaneous) orbital period of the smaller body remains very near that of the larger body, and if its orbit is a little more eccentric than that of the larger body, during every period it appears to trace an ellipse around a point on the larger object's orbit. However, the loop is not closed but drifts forward or backward so that the point it circles will appear to move smoothly along the larger body's orbit over a long period of time. When the object approaches the larger body closely at either end of its trajectory, its apparent direction changes. Over an entire cycle the center traces the outline of a horseshoe, with the larger body between the 'horns'. Asteroids in horseshoe orbits with respect to Earth include 54509 YORP, , , and possibly . A broader definition includes 3753 Cruith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moonlet
A moonlet, minor moon, minor natural satellite, or minor satellite is a particularly small natural satellite orbiting a planet, dwarf planet, or other minor planet. Up until 1995, moonlets were only hypothetical components of Saturn's F-ring structure, but in that year, the Earth passed through Saturn's ring plane. The Hubble Space Telescope and the European Southern Observatory both captured objects orbiting close or near the F-ring. In 2004, Cassini–Huygens , Cassini caught an object 4–5 kilometers in diameter on the outer ring of the F-ring and then 5 hours later on the inner F-ring, showing that the object had orbited. Three different types of small moons have been called moonlets: * A belt of objects embedded in a planetary ring, especially around Saturn, such as those in the Rings of Saturn#A Ring, A Ring, S/2009 S 1 in the B Ring (Moons of Saturn#Ring moonlets, "propeller" moonlets), and those in the Rings of Saturn#F Ring, F Ring * Occasionally asteroid moons, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empanada
An empanada is a type of baked or fried turnover consisting of pastry and filling, common in Spanish, other Southern European, Latin American, and Iberian-influenced cultures around the world. The name comes from the Spanish (to bread, i.e., to coat with bread), and translates as 'breaded', that is, wrapped or coated in bread. They are made by folding dough over a filling, which may consist of meat, cheese, tomato, corn, or other ingredients, and then cooking the resulting turnover, either by baking or frying. Origins The origin of empanadas is unknown but they are thought to have originated in Galicia, a region in northwest Spain. A cookbook published in Catalan in 1520, ''Llibre del Coch'' by Robert de Nola, mentions empanadas filled with seafood in the recipes for Catalan, Italian, French, and Arabian food. By country and region Argentina Argentine empanadas are often served during parties and festivals as a starter or main course. Shops specialize in freshly m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlas (moon)
Atlas is an inner satellite of Saturn which was discovered by Richard Terrile in 1980 from Voyager photos and was designated . In 1983 it was officially named after Atlas of Greek mythology, because it "holds the rings on its shoulders" like the Titan Atlas held the sky up above the Earth. It is also designated . Atlas is the closest satellite to the sharp outer edge of the A ring, and was long thought to be a shepherd satellite for this ring. However, now it is known that the outer edge of the ring is instead maintained by a 7:6 orbital resonance with the larger but more distant moons Janus and Epimetheus. In 2004 a faint, thin ring, temporarily designated , was discovered in the Atlantean orbit. High-resolution images taken in June 2005 by '' Cassini'' revealed Atlas to have a roughly spherical centre surrounded by a large, smooth equatorial ridge. The most likely explanation for this unusual and prominent structure is that ring material swept up by the moon accumulates on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equatorial Ridge
Equatorial ridges are a feature of at least three of Saturn's moons: the large moon Iapetus and the tiny moons Atlas and Pan. They are ridges that closely follow the moons' equators. They appear to be unique to the Saturnian system, but it is uncertain whether the occurrences are related or a coincidence. All three were discovered by the '' Cassini'' probe in 2005. Daphnis also appears to have such a ridge. The ridge on Iapetus is nearly 20 km wide, 13 km high and 1,300 km long. The ridge on Atlas is proportionally even more remarkable given the moon's much smaller size, giving it a disk-like shape. Images of Pan show a structure similar to that of Atlas. Formation It is not certain how these ridges formed, or whether there is any connection between them. Because Atlas and Pan orbit within the rings of Saturn, a likely explanation for their ridges is that they sweep up ring particles as they orbit, which build up around their equators. This theory is less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Photojournal
Planetary means relating to a planet or planets. It can also refer to: ;Science * Planetary habitability, the measure of an astronomical body's potential to develop and sustain life * Planetary nebula, an astronomical object ;People * Planetary (rapper), one half of east coast rap group OuterSpace ;Arts, entertainment, and media * ''Planetary'' (comics), a comic book series by Warren Ellis and John Cassaday * "Planetary (Go!)", a 2011 song by rock band My Chemical Romance * ''Planetary Radio'', a public radio show about space exploration, produced by The Planetary Society ;Organizations * The Planetary Society, the Earth's largest space interest group ;Technology * Epicyclic gearing (planetary gearing), an automotive transmission technology * Planetary scanner A planetary scanner (also called an orbital scanner) is a type of image scanner for making scans of rare books and other easily damaged documents. In essence, such a scanner is a mounted camera taking photos of a well- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_edge-on.jpg "Click for more on -> Pan (moon)")
_2010_SO16_orbit.gif "Click for more on -> Horseshoe Orbit")
_caseras.JPG "Click for more on -> Empanada")