Pan is the innermost named moon of Saturn. It is a small, walnut-shaped moon 35 kilometres across and 23 km wide that orbits within the Encke Gap in Saturn's A Ring. Pan is a ring is responsible for keeping the Encke Gap free of ring particles, it was discovered by Mark R. Showalter in 1990 from analysis of old Voyager 2 probe photos and received the provisional designation S/1981 S 13 because the discovery images dated back to 1981; 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 gravitational disturbance. In 1986 Showalter et al. inferred its mass by modeling its gravitational wake. They arrived at a precise prediction of 133,603 ± 10 km for the semi-major axis and a mass of 5–10×10−12 Saturn masses, inferred that there was only a single moon within the Encke gap; the actual semi-major axis differs by 19 km and the actual mass is 8.6×10−12 of Saturn's. The moon was found within 1° of the predicted position.
The search was undertaken by considering all Voyager 2 images and using a computer calculation to predict whether the moon would be visible under sufficiently favorable conditions in each one. Every qualifying Voyager 2 image with resolution better than ~50 km/pixel shows Pan clearly. In all, it appears in eleven Voyager 2 images; the moon was named on 16 September 1991, after the mythological Pan, the god of shepherds. This is a reference to Pan's role as a shepherd moon, it is designated Saturn XVIII. The eccentricity of Pan's orbit causes its distance from Saturn to vary by ~4 km, its inclination, which would cause it to move up and down, is not distinguishable from zero with present data. The Encke Gap, within which Pan orbits, is about 325 km wide. Cassini scientists have described Pan as "walnut-shaped" owing to the equatorial ridge, similar to that on Atlas, visible in images; the ridge is due to ring material. It has been referred to by journalists as a space empanada, a form of stuffed bread or pastry, as well as a ravioli.
The Encke Gap contains a ringlet, coincident with Pan's orbit, indicating that Pan maintains the particles in horseshoe orbits. A second ringlet is periodically disrupted by Pan to how the F Ring is disturbed by Prometheus. Notes Citations Pan Profile by NASA's Solar System Exploration The Planetary Society: Pan
An impact crater is an circular depression in the surface of a planet, moon, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, bowl-shaped depressions to large, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth. Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Callisto and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Mars, Europa, Io and Titan, visible impact craters are less common because they become eroded, buried or transformed by tectonics over time. Where such processes have destroyed most of the original crater topography, the terms impact structure or astrobleme are more used.
In early literature, before the significance of impact cratering was recognised, the terms cryptoexplosion or cryptovolcanic structure were used to describe what are now recognised as impact-related features on Earth. The cratering records of old surfaces, such as Mercury, the Moon, the southern highlands of Mars, record a period of intense early bombardment in the inner Solar System around 3.9 billion years ago. The rate of crater production on Earth has since been lower, but it is appreciable nonetheless; this indicates that there should be far more young craters on the planet than have been discovered so far. The cratering rate in the inner solar system fluctuates as a consequence of collisions in the asteroid belt that create a family of fragments that are sent cascading into the inner solar system. Formed in a collision 160 million years ago, the Baptistina family of asteroids is thought to have caused a large spike in the impact rate causing the Chicxulub impact that may have triggered the extinction of the non-avian dinosaurs 66 million years ago.
Note that the rate of impact cratering in the outer Solar System could be different from the inner Solar System. Although Earth's active surface processes destroy the impact record, about 190 terrestrial impact craters have been identified; these range in diameter from a few tens of meters up to about 300 km, they range in age from recent times to more than two billion years, though most are less than 500 million years old because geological processes tend to obliterate older craters. They are selectively found in the stable interior regions of continents. Few undersea craters have been discovered because of the difficulty of surveying the sea floor, the rapid rate of change of the ocean bottom, the subduction of the ocean floor into Earth's interior by processes of plate tectonics. Impact craters are not to be confused with landforms that may appear similar, including calderas, glacial cirques, ring dikes, salt domes, others. Daniel M. Barringer, a mining engineer, was convinced that the crater he owned, Meteor Crater, was of cosmic origin.
Yet, most geologists at the time assumed. In the 1920s, the American geologist Walter H. Bucher studied a number of sites now recognized as impact craters in the United States, he concluded they had been created by some great explosive event, but believed that this force was volcanic in origin. However, in 1936, the geologists John D. Boon and Claude C. Albritton Jr. revisited Bucher's studies and concluded that the craters that he studied were formed by impacts. Grove Karl Gilbert suggested in 1893. Ralph Baldwin in 1949 wrote that the Moon's craters were of impact origin. Around 1960, Gene Shoemaker revived the idea. According to David H. Levy, Gene "saw the craters on the Moon as logical impact sites that were formed not in eons, but explosively, in seconds." For his Ph. D. degree at Princeton, under the guidance of Harry Hammond Hess, Shoemaker studied the impact dynamics of Barringer Meteor Crater. Shoemaker noted Meteor Crater had the same form and structure as two explosion craters created from atomic bomb tests at the Nevada Test Site, notably Jangle U in 1951 and Teapot Ess in 1955.
In 1960, Edward C. T. Chao and Shoemaker identified at Meteor Crater, proving the crater was formed from an impact generating high temperatures and pressures, they followed this discovery with the identification of coesite within suevite at Nördlinger Ries, proving its impact origin. Armed with the knowledge of shock-metamorphic features, Carlyle S. Beals and colleagues at the Dominion Astrophysical Observatory in Victoria, British Columbia and Wolf von Engelhardt of the University of Tübingen in Germany began a methodical search for impact craters. By 1970, they had tentatively identified more than 50. Although their work was controversial, the American Apollo Moon landings, which were in progress at the time, provided supportive evidence by recognizing the rate of impact cratering on the Moon; because the processes of erosion on the Moon are minimal, craters persist. Since the Earth could be expected to have the same cratering rate as the Moon, it became clear that the Earth had suffered far more impacts than could be seen by counting evident craters.
Impact cratering invo
Amalthea is the third moon of Jupiter in order of distance from the planet. It was discovered on 9 September 1892, by Edward Emerson Barnard and named after Amalthea, a nymph in Greek mythology, it is known as Jupiter V. Amalthea is in a close orbit around Jupiter and is within the outer edge of the Amalthea Gossamer Ring, formed from dust ejected from its surface. From its surface, Jupiter would appear 46.5 degrees in diameter. Amalthea is the largest of the inner satellites of Jupiter. Irregularly shaped and reddish in color, it is thought to consist of porous water ice with unknown amounts of other materials, its surface features include large ridges. Amalthea was photographed in 1979 by the Voyager 1 and 2 spacecraft, in more detail, by the Galileo orbiter in the 1990s. Amalthea was discovered on 9 September 1892, by Edward Emerson Barnard using the 36 inch refractor telescope at Lick Observatory, it was the last planetary satellite to be discovered by direct visual observation and was the first new satellite of Jupiter since Galileo Galilei's discovery of the Galilean satellites in 1610.
Amalthea is named after the nymph Amalthea from Greek mythology, who nursed the infant Zeus with goat's milk. Its Roman numeral designation is Jupiter V; the name "Amalthea" was not formally adopted by the IAU until 1976, although it had been in informal use for many decades. The name was suggested by Camille Flammarion. Before 1976, Amalthea was most known as Jupiter V. Amalthea orbits Jupiter at a distance of 181 000 km; the orbit of Amalthea has an eccentricity of 0.003 and an inclination of 0.37° relative to the equator of Jupiter. Such appreciably nonzero values of inclination and eccentricity, though still small, are unusual for an inner satellite and can be explained by the influence of the innermost Galilean satellite, Io: in the past Amalthea has passed through several mean-motion resonances with Io that have excited its inclination and eccentricity. Amalthea's orbit lies near the outer edge of the Amalthea Gossamer Ring, composed of the dust ejected from the satellite; the surface of Amalthea is red.
The reddish color may be due to sulfur originating from some other non-ice material. Bright patches of less red tint appear on the major slopes of Amalthea, but the nature of this color is unknown; the surface of Amalthea is brighter than surfaces of other inner satellites of Jupiter. There is a substantial asymmetry between leading and trailing hemispheres: the leading hemisphere is 1.3 times brighter than the trailing one. The asymmetry is caused by the higher velocity and frequency of impacts on the leading hemisphere, which excavate a bright material—presumably ice—from the interior of the moon. Amalthea is irregularly shaped, with the best ellipsoidal approximation being 250 × 146 × 128 km. From this, Amalthea's surface area is between 88,000 and 170,000 square kilometers, or somewhere near 130,000. Like all other inner moons of Jupiter it is tidally locked with the planet, the long axis pointing towards Jupiter at all times, its surface is scarred by craters, some of which are large relative to the size of the moon: Pan, the largest crater, measures 100 km across and is at least 8 km deep.
Another crater, measures 80 km across and is twice as deep as Pan. Amalthea has several prominent bright spots, they are Ida Facula, with width reaching up to 25 km. They are located on the edge of ridges. Amalthea's irregular shape and large size led in the past to a conclusion that it is a strong, rigid body, where it was argued that a body composed of ices or other weak materials would have been pulled into a more spherical shape by its own gravity. However, on 5 November 2002, the Galileo orbiter made a targeted flyby that came within 160 km of Amalthea and the deflection of its orbit was used to compute the moon's mass. In the end, Amalthea's density was found to be as low as 0.86 g/cm3, so it must be either a icy body or porous "rubble pile" or, more something in between. Recent measurements of infrared spectra from the Subaru telescope suggest that the moon indeed contains hydrous minerals, indicating that it cannot have formed in its current position, since the hot primordial Jupiter would have melted it.
It is therefore to have formed farther from the planet or to be a captured Solar System body. No images were taken during this flyby, the resolution of other available images is low. Amalthea radiates more heat than it receives from the Sun, due to the influence of Jovian heat flux, sunlight reflected from the planet, charged particle bombardment; this is a trait shared with Io, although for different reasons. There are four named geological features on Amalthea: two faculae; the faculae are located on the edge of a ridge on the anti-Jupiter side of Amalthea. Due to tidal force from Jupiter and Amalthea's low density and irregular shape, the escape velocity at its surface points closest to and furthest from Jupiter is no more than 1 m/s and dust can escape from it after, e.g. micrometeorite impacts. During its flyby of Amalthea, the Galileo orbiter's star scanner detected nine fla
In Greek mythology, Amaltheia is the most-frequently mentioned foster-mother of Zeus. The name Amaltheia, in Greek "tender goddess", is an epithet, signifying the presence of an earlier nurturing goddess, whom the Hellenes, whose myths we know, knew to be located in Crete, where Minoans may have called her a version of "Dikte". There were different traditions regarding Amaltheia. Amaltheia is sometimes represented as the goat who nurtured the infant-god in a cave in Cretan Mount Aigaion, sometimes as a goat-tending nymph of uncertain parentage, The possession of multiple and uncertain mythological parents indicates wide worship of a deity in many cultures having varying local traditions. Other names, like Adrasteia, the nymph of Mount Ida, or Adamanthea, which appear in mythology handbooks, are duplicates of Amaltheia. In the tradition represented by Hesiod's Theogony, Cronus swallowed all of his children after birth; the mother goddess Rhea, Zeus' mother, deceived her brother consort Cronus by giving him a stone wrapped to look like a baby instead of Zeus.
Since she instead gave the infant Zeus to Adamanthea to nurse in a cave on a mountain in Crete, it is clear that Adamanthea is a doublet of Amaltheia. In many literary references, the Greek tradition relates that in order that Cronus should not hear the wailing of the infant, Amaltheia gathered about the cave the Kuretes or the Korybantes to dance and clash their spears against their shields. Still a baby, Zeus would have broken off one of Amalthea's horns while playing, which would become the cornucopia, turning Amalthea into the first unicorn, a reference used by Peter S. Beagle in his novel The Last Unicorn, as Schmendrick, the magician, called the main character "Lady Amalthea", without giving any explanation to his choice. Amaltheia's skin, or that of her goat, taken by Zeus in honor of her when she died, became the protective aegis in some traditions. "Amaltheia was placed amongst the stars as the constellation Capra—the group of stars surrounding Capella on the arm of Auriga the Charioteer."
Capra means "she-goat" and the star-name Capella is the "little goat", but some modern readers confuse her with the male sea-goat of the Zodiac, who bears no relation to Amaltheia, no connection in a Greek or Latin literary source nor any ritual or inscription to join the two. Hyginus describes this catasterism in the Poetic Astronomy, in speaking of Auriga, the Charioteer: Auðumbla, primeval cow in Norse mythology who nourished the primordial entities Ymir and Búri Apollodorus, The Library, with an English Translation by Sir James George Frazer, F. B. A. F. R. S. in 2 Volumes. Cambridge, MA, Harvard University Press. Online version at the Perseus Digital Library. Gee, Ovid and Augustus: Astronomy in Ovid's Fasti, Cambridge University Press, 2000. ISBN 9780521651875. Hesiod, Theogony, in The Homeric Hymns and Homerica with an English Translation by Hugh G. Evelyn-White, Cambridge, MA. Harvard University Press. Online version at the Perseus Digital Library. Hyginus, Gaius Julius, Fabulae in Apollodorus' Library and Hyginus' Fabuae: Two Handbooks of Greek Mythology, with Introductions by R. Scott Smith and Stephen M. Trzaskoma, Hackett Publishing Company, 2007.
ISBN 978-0-87220-821-6. Kerenyi, Karl; the Gods of the Greeks. London: Thames & Hudson, 1951. Smith, William. "Amaltheia" West, M. L; the Orphic Poems, Clarendon Press. ISBN 978-0-19-814854-8
Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a giant planet with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined. Jupiter and Saturn are gas giants. Jupiter has been known to astronomers since antiquity, it is named after the Roman god Jupiter. When viewed from Earth, Jupiter can reach an apparent magnitude of −2.94, bright enough for its reflected light to cast shadows, making it on average the third-brightest natural object in the night sky after the Moon and Venus. Jupiter is composed of hydrogen with a quarter of its mass being helium, though helium comprises only about a tenth of the number of molecules, it may have a rocky core of heavier elements, but like the other giant planets, Jupiter lacks a well-defined solid surface. Because of its rapid rotation, the planet's shape is that of an oblate spheroid; the outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries.
A prominent result is the Great Red Spot, a giant storm, known to have existed since at least the 17th century when it was first seen by telescope. Surrounding Jupiter is a powerful magnetosphere. Jupiter has 79 known moons, including the four large Galilean moons discovered by Galileo Galilei in 1610. Ganymede, the largest of these, has a diameter greater than that of the planet Mercury. Jupiter has been explored on several occasions by robotic spacecraft, most notably during the early Pioneer and Voyager flyby missions and by the Galileo orbiter. In late February 2007, Jupiter was visited by the New Horizons probe, which used Jupiter's gravity to increase its speed and bend its trajectory en route to Pluto; the latest probe to visit the planet is Juno, which entered into orbit around Jupiter on July 4, 2016. Future targets for exploration in the Jupiter system include the probable ice-covered liquid ocean of its moon Europa. Astronomers have discovered nearly 500 planetary systems with multiple planets.
These systems include a few planets with masses several times greater than Earth's, orbiting closer to their star than Mercury is to the Sun, sometimes Jupiter-mass gas giants close to their star. Earth and its neighbor planets may have formed from fragments of planets after collisions with Jupiter destroyed those super-Earths near the Sun; as Jupiter came toward the inner Solar System, in what theorists call the grand tack hypothesis, gravitational tugs and pulls occurred causing a series of collisions between the super-Earths as their orbits began to overlap. Researchers from Lund University found that Jupiter's migration went on for around 700,000 years, in a period 2-3 million years after the celestial body started its life as an ice asteroid far from the sun; the journey inwards in the solar system followed a spiraling course in which Jupiter continued to circle around the sun, albeit in an tight path. The reason behind the actual migration relates to gravitational forces from the surrounding gases in the solar system.
Jupiter moving out of the inner Solar System would have allowed the formation of inner planets, including Earth. Jupiter is composed of gaseous and liquid matter, it is the largest of hence its largest planet. It has a diameter of 142,984 km at its equator; the average density of Jupiter, 1.326 g/cm3, is the second highest of the giant planets, but lower than those of the four terrestrial planets. Jupiter's upper atmosphere is about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules. A helium atom has about four times as much mass as a hydrogen atom, so the composition changes when described as the proportion of mass contributed by different atoms. Thus, Jupiter's atmosphere is 75% hydrogen and 24% helium by mass, with the remaining one percent of the mass consisting of other elements; the atmosphere contains trace amounts of methane, water vapor and silicon-based compounds. There are traces of carbon, hydrogen sulfide, oxygen and sulfur; the outermost layer of the atmosphere contains crystals of frozen ammonia.
The interior contains denser materials—by mass it is 71% hydrogen, 24% helium, 5% other elements. Through infrared and ultraviolet measurements, trace amounts of benzene and other hydrocarbons have been found; the atmospheric proportions of hydrogen and helium are close to the theoretical composition of the primordial solar nebula. Neon in the upper atmosphere only consists of 20 parts per million by mass, about a tenth as abundant as in the Sun. Helium is depleted to about 80% of the Sun's helium composition; this depletion is a result of precipitation of these elements into the interior of the planet. Based on spectroscopy, Saturn is thought to be similar in composition to Jupiter, but the other giant planets Uranus and Neptune have less hydrogen and helium and more ices and are thus now termed ice giants. Jupiter's mass is 2.5 times that of all the other planets in the Solar System combined—this is so massive that its barycenter with the Sun lies above the Sun's surface at 1.068 solar radii from the Sun's center.
Jupiter is much larger than Earth and less dense: its volume is that of about 1,321 Earths, but it is only 318 times as massive. Jupiter's radius is about 1/10 the radius of the Sun, its mass is 0.001 times the mass of the Sun, so the densities of the two bodies are similar. A "Jupiter mass" is used as a u
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, the natural hazards that threaten it; the organization has four major science disciplines, concerning biology, geography and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility; the USGS is a bureau of the United States Department of the Interior. The USGS employs 8,670 people and is headquartered in Reston, Virginia; the USGS has major offices near Lakewood, Colorado, at the Denver Federal Center, Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world." The agency's previous slogan, adopted on the occasion of its hundredth anniversary, was "Earth Science in the Public Service." Since 2012, the USGS science focus is directed at six topical "Mission Areas", namely Climate and Land Use Change, Core Science Systems, Ecosystems and Minerals and Environmental Health, Natural Hazards, Water.
In December 2012, the USGS split the Energy and Minerals and Environmental Health Mission Area resulting in seven topical Mission Areas, with the two new areas being: Energy and Minerals and Environmental Health. Administratively, it is divided into six Regional Units. Other specific programs include: Earthquake Hazards Program monitors earthquake activity worldwide; the National Earthquake Information Center in Golden, Colorado on the campus of the Colorado School of Mines detects the location and magnitude of global earthquakes. The USGS runs or supports several regional monitoring networks in the United States under the umbrella of the Advanced National Seismic System; the USGS informs authorities, emergency responders, the media, the public, both domestic and worldwide, about significant earthquakes. It maintains long-term archives of earthquake data for scientific and engineering research, it conducts and supports research on long-term seismic hazards. USGS has released the UCERF California earthquake forecast.
As of 2005, the agency is working to create a National Volcano Early Warning System by improving the instrumentation monitoring the 169 volcanoes in U. S. territory and by establishing methods for measuring the relative threats posed at each site. The USGS National Geomagnetism Program monitors the magnetic field at magnetic observatories and distributes magnetometer data in real time; the USGS collaborates with Canadian and Mexican government scientists, along with the Commission for Environmental Cooperation, to produce the North American Environmental Atlas, used to depict and track environmental issues for a continental perspective. The USGS operates the streamgaging network for the United States, with over 7400 streamgages. Real-time streamflow data are available online. National Climate Change and Wildlife Science Center implements partner-driven science to improve understanding of past and present land use change, develops relevant climate and land use forecasts, identifies lands and communities that are most vulnerable to adverse impacts of change from the local to global scale.
Since 1962, the Astrogeology Research Program has been involved in global and planetary exploration and mapping. In collaboration with Stanford University, the USGS operates the USGS-Stanford Ion Microprobe Laboratory, a world-class analytical facility for U--Pb geochronology and trace element analyses of minerals and other earth materials. USGS operates a number of water related programs, notably the National Streamflow Information Program and National Water-Quality Assessment Program. USGS Water data is publicly available from their National Water Information System database; the USGS operates the National Wildlife Health Center, whose mission is "to serve the nation and its natural resources by providing sound science and technical support, to disseminate information to promote science-based decisions affecting wildlife and ecosystem health. The NWHC provides information, technical assistance, research and leadership on national and international wildlife health issues." It is the agency responsible for surveillance of H5N1 avian influenza outbreaks in the United States.
The USGS runs 17 biological research centers in the United States, including the Patuxent Wildlife Research Center. The USGS is investigating collaboration with the social networking site Twitter to allow for more rapid construction of ShakeMaps; the USGS produces several national series of topographic maps which vary in scale and extent, with some wide gaps in coverage, notably the complete absence of 1:50,000 scale topographic maps or their equivalent. The largest and best-known topographic series is the 7.5-minute, 1:24,000 scale, quadrangle, a non-metric scale unique to the United States. Each of these maps covers an area bounded by two lines of latitude and two lines of longitude spaced 7.5 minutes apart. Nearly 57,000 individual maps in this series cover the 48 contiguous states, Hawaii, U. S. territories, areas of Alaska near Anchorage and Prudhoe Bay. The area covered by each map varies with the latitude of its represented location due to convergence of the meridians. At lower latitudes, near 30° north, a 7.5-minute quadrangle contains an area of about 64 square miles.
At 49° north latitude, 49 square miles are contained within a quadrangle of that size. As a unique non-metric map scale, the 1:24,000 scale requires a separate and specialized romer scale for pl
Greek mythology is the body of myths told by the ancient Greeks. These stories concern the origin and the nature of the world, the lives and activities of deities and mythological creatures, the origins and significance of the ancient Greeks' own cult and ritual practices. Modern scholars study the myths in an attempt to shed light on the religious and political institutions of ancient Greece and its civilization, to gain understanding of the nature of myth-making itself; the Greek myths were propagated in an oral-poetic tradition most by Minoan and Mycenaean singers starting in the 18th century BC. Two poems by Homer's near contemporary Hesiod, the Theogony and the Works and Days, contain accounts of the genesis of the world, the succession of divine rulers, the succession of human ages, the origin of human woes, the origin of sacrificial practices. Myths are preserved in the Homeric Hymns, in fragments of epic poems of the Epic Cycle, in lyric poems, in the works of the tragedians and comedians of the fifth century BC, in writings of scholars and poets of the Hellenistic Age, in texts from the time of the Roman Empire by writers such as Plutarch and Pausanias.
Aside from this narrative deposit in ancient Greek literature, pictorial representations of gods and mythic episodes featured prominently in ancient vase-paintings and the decoration of votive gifts and many other artifacts. Geometric designs on pottery of the eighth century BC depict scenes from the Trojan cycle as well as the adventures of Heracles. In the succeeding Archaic and Hellenistic periods and various other mythological scenes appear, supplementing the existing literary evidence. Greek mythology has had an extensive influence on the culture and literature of Western civilization and remains part of Western heritage and language. Poets and artists from ancient times to the present have derived inspiration from Greek mythology and have discovered contemporary significance and relevance in the themes. Greek mythology is known today from Greek literature and representations on visual media dating from the Geometric period from c. 900 BC to c. 800 BC onward. In fact and archaeological sources integrate, sometimes mutually supportive and sometimes in conflict.
Mythical narration plays an important role in nearly every genre of Greek literature. The only general mythographical handbook to survive from Greek antiquity was the Library of Pseudo-Apollodorus; this work attempts to reconcile the contradictory tales of the poets and provides a grand summary of traditional Greek mythology and heroic legends. Apollodorus of Athens wrote on many of these topics, his writings may have formed the basis for the collection. Among the earliest literary sources are the Iliad and the Odyssey. Other poets completed the "epic cycle", but these and lesser poems now are lost entirely. Despite their traditional name, the "Homeric Hymns" have no direct connection with Homer, they are choral hymns from the earlier part of the so-called Lyric age. Hesiod, a possible contemporary with Homer, offers in his Theogony the fullest account of the earliest Greek myths, dealing with the creation of the world. Hesiod's Works and Days, a didactic poem about farming life includes the myths of Prometheus and the Five Ages.
The poet gives advice on the best way to succeed in a dangerous world, rendered yet more dangerous by its gods. Lyrical poets took their subjects from myth, but their treatment became less narrative and more allusive. Greek lyric poets, including Pindar and Simonides, bucolic poets such as Theocritus and Bion, relate individual mythological incidents. Additionally, myth was central to classical Athenian drama; the tragic playwrights Aeschylus and Euripides took most of their plots from myths of the age of heroes and the Trojan War. Many of the great tragic stories took on their classic form in these tragedies; the comic playwright Aristophanes used myths, in The Birds and The Frogs. Historians Herodotus and Diodorus Siculus, geographers Pausanias and Strabo, who traveled throughout the Greek world and noted the stories they heard, supplied numerous local myths and legends giving little-known alternative versions. Herodotus in particular, searched the various traditions presented him and found the historical or mythological roots in the confrontation between Greece and the East.
Herodotus attempted to reconcile the blending of differing cultural concepts. The poetry of the Hellenistic and Roman ages was composed as a literary rather than cultic exercise, it contains many important details that would otherwise be lost. This category includes the works of: The Roman poets Ovid, Valerius Flaccus and Virgil with Servius's commentary; the Greek poets of the Late Antique period: Nonnus, Antoninus Liberalis, Quintus Smyrnaeus. The Greek poets of the Hellenistic period: Apollonius of Rhodes, Pseudo-Eratosthenes, Parthenius. Prose writers from the same periods who make reference to myths includ