133-586: The Spitzer Infrared Nearby Galaxies Survey ( SINGS ) was a survey of 75 galaxies using the Spitzer Space Telescope , carried out between 2003 and 2006. One of the telescope's six Legacy Science Projects, SINGS collected a comprehensive set of spectroscopic data in the infrared region, which, in conjunction with measurements at other wavelengths, was intended to provide insights into star formation and other processes occurring within these galaxies. This astronomical catalog article
266-656: A "small cloud". In 964, he probably mentioned the Large Magellanic Cloud in his Book of Fixed Stars , referring to "Al Bakr of the southern Arabs", since at a declination of about 70° south it was not visible where he lived. It was not well known to Europeans until Magellan 's voyage in the 16th century. The Andromeda Galaxy was later independently noted by Simon Marius in 1612. In 1734, philosopher Emanuel Swedenborg in his Principia speculated that there might be other galaxies outside that were formed into galactic clusters that were minuscule parts of
399-494: A bride, and names it Daidale. When preparations are being made for the wedding, Hera rushes down from Cithaeron, followed by the women of Plataia , and upon discovering the trick, the couple are reconciled, with the matter ending in joy and laughter among all involved. After his marriage to Hera, different authors describe Zeus's numerous affairs with various mortal women. In many of these affairs, Zeus transforms himself into an animal, someone else, or some other form. According to
532-452: A chain reaction of star-building that spreads throughout the gaseous region. Only when the available gas is nearly consumed or dispersed does the activity end. Starbursts are often associated with merging or interacting galaxies. The prototype example of such a starburst-forming interaction is M82 , which experienced a close encounter with the larger M81 . Irregular galaxies often exhibit spaced knots of starburst activity. A radio galaxy
665-424: A cuckoo bird, landing on Mount Thornax. He creates a terrible storm, and when Hera arrives at the mountain and sees the bird, which sits on her lap, she takes pity on it, laying her cloak over it. Zeus then transforms back and takes hold of her; when she refuses to have intercourse with him because of their mother, he promises that she will become his wife. Pausanias similarly refers to Zeus transforming himself into
798-416: A cuckoo to woo Hera, and identifies the location as Mount Thornax. According to a version from Plutarch , as recorded by Eusebius in his Praeparatio evangelica , Hera is raised by a nymph named Macris on the island of Euboea when Zeus kidnaps her, taking her to Mount Cithaeron , where they find a shady hollow, which serves as a "natural bridal chamber". When Macris comes to look for Hera, Cithaeron,
931-684: A debate took place between Harlow Shapley and Heber Curtis , the Great Debate , concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the universe. To support his claim that the Great Andromeda Nebula is an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift. In 1922, the Estonian astronomer Ernst Öpik gave
1064-536: A distance determination that supported the theory that the Andromeda Nebula is indeed a distant extra-galactic object. Using the new 100-inch Mt. Wilson telescope, Edwin Hubble was able to resolve the outer parts of some spiral nebulae as collections of individual stars and identified some Cepheid variables , thus allowing him to estimate the distance to the nebulae: they were far too distant to be part of
1197-921: A few have well-established names, such as the Andromeda Galaxy , the Magellanic Clouds , the Whirlpool Galaxy , and the Sombrero Galaxy . Astronomers work with numbers from certain catalogues, such as the Messier catalogue , the NGC ( New General Catalogue ), the IC ( Index Catalogue ), the CGCG ( Catalogue of Galaxies and of Clusters of Galaxies ), the MCG ( Morphological Catalogue of Galaxies ),
1330-528: A few nearby bright galaxies, like the Andromeda Galaxy , began resolving them into huge conglomerations of stars, but based simply on the apparent faintness and sheer population of stars, the true distances of these objects placed them well beyond the Milky Way. For this reason they were popularly called island universes , but this term quickly fell into disuse, as the word universe implied the entirety of existence. Instead, they became known simply as galaxies. Millions of galaxies have been catalogued, but only
1463-452: A folk etymology of Zeus meaning "cause of life always to all things", because of puns between alternate titles of Zeus ( Zen and Dia ) with the Greek words for life and "because of". This etymology, along with Plato's entire method of deriving etymologies, is not supported by modern scholarship. Diodorus Siculus wrote that Zeus was also called Zen, because the humans believed that he was
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#17327808626391596-418: A function of their radius (or distance from their cores) falls off more slowly than their smaller counterparts. The formation of these cD galaxies remains an active area of research, but the leading model is that they are the result of the mergers of smaller galaxies in the environments of dense clusters, or even those outside of clusters with random overdensities. These processes are the mechanisms that drive
1729-429: A low portion of open clusters and a reduced rate of new star formation. Instead, they are dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions. The stars contain low abundances of heavy elements because star formation ceases after the initial burst. In this sense they have some similarity to the much smaller globular clusters . The largest galaxies are
1862-489: A man who was guilty of murdering his father-in-law, by purifying him and bringing him to Olympus. However, Ixion started to lust after Hera. Hera complained about this to her husband, and Zeus decided to test Ixion. Zeus fashioned a cloud that resembles Hera ( Nephele ) and laid the cloud-Hera in Ixion's bed. Ixion coupled with Nephele, resulting in the birth of Centaurus . Zeus punished Ixion for lusting after Hera by tying him to
1995-579: A more complex narrative. Typhon is, similarly to in Hesiod, the child of Gaia and Tartarus, produced out of anger at Zeus's defeat of the Giants. The monster attacks heaven, and all of the gods, out of fear, transform into animals and flee to Egypt, except for Zeus, who attacks the monster with his thunderbolt and sickle. Typhon is wounded and retreats to Mount Kasios in Syria, where Zeus grapples with him, giving
2128-417: A pattern that can be theoretically shown to result from a disturbance in a uniformly rotating mass of stars. Like the stars, the spiral arms rotate around the center, but they do so with constant angular velocity . The spiral arms are thought to be areas of high-density matter, or " density waves ". As stars move through an arm, the space velocity of each stellar system is modified by the gravitational force of
2261-462: A plan to save her child and bring retribution to Cronus. Following her parents' instructions, she travels to Lyctus in Crete , where she gives birth to Zeus, handing the newborn child over to Gaia for her to raise, and Gaia takes him to a cave on Mount Aegaeon (Aegeum). Rhea then gives to Cronus, in the place of a child, a stone wrapped in swaddling clothes, which he promptly swallows, unaware that it
2394-400: A plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of dark matter which extends beyond the visible component, as demonstrated by the universal rotation curve concept. Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In
2527-522: A priestess of Hera, who is subsequently turned into a cow, and suffers at Hera's hands: according to Apollodorus, Hera sends a gadfly to sting the cow, driving her all the way to Egypt, where she is finally transformed back into human form. In later accounts of Zeus's affair with Semele , a daughter of Cadmus and Harmonia , Hera tricks her into persuading Zeus to grant her any promise. Semele asks him to come to her as he comes to his own wife Hera, and when Zeus upholds this promise, she dies out of fright and
2660-438: A punishing gift to compensate for the boon they had been given. He commands Hephaestus to mold from earth the first woman, a "beautiful evil" whose descendants would torment the human race. After Hephaestus does so, several other gods contribute to her creation. Hermes names the woman ' Pandora '. Pandora was given in marriage to Prometheus's brother Epimetheus . Zeus gave her a jar which contained many evils. Pandora opened
2793-438: A reserve of cold gas that forms giant molecular clouds . Some galaxies have been observed to form stars at an exceptional rate, which is known as a starburst . If they continue to do so, they would consume their reserve of gas in a time span less than the galaxy's lifespan. Hence starburst activity usually lasts only about ten million years, a relatively brief period in a galaxy's history. Starburst galaxies were more common during
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#17327808626392926-435: A rotating bar structure in the center of this galaxy. With improved radio telescopes , hydrogen gas could also be traced in other galaxies. In the 1970s, Vera Rubin uncovered a discrepancy between observed galactic rotation speed and that predicted by the visible mass of stars and gas. Today, the galaxy rotation problem is thought to be explained by the presence of large quantities of unseen dark matter . Beginning in
3059-541: A scholion on the Iliad (citing Hesiod and Bacchylides ), when Europa is picking flowers with her female companions in a meadow in Phoenicia, Zeus transforms himself into a bull, lures her from the others, and then carries her across the sea to the island of Crete, where he resumes his usual form to sleep with her. In Euripides ' Helen , Zeus takes the form of a swan, and after being chased by an eagle, finds shelter in
3192-623: A similar ten-year war against the Titans, until, upon the prophesying of Gaia, he releases the Cyclopes and Hundred-Handers from Tartarus, first slaying their warder, Campe . The Cyclopes give him his thunderbolt, Poseidon his trident and Hades his helmet of invisibility, and the Titans are defeated and the Hundred-Handers made their guards. According to the Iliad , after the battle with
3325-488: A single larger galaxy; the Milky Way has at least a dozen such satellites, with an estimated 300–500 yet to be discovered. Most of the information we have about dwarf galaxies come from observations of the local group , containing two spiral galaxies, the Milky Way and Andromeda, and many dwarf galaxies. These dwarf galaxies are classified as either irregular or dwarf elliptical / dwarf spheroidal galaxies . A study of 27 Milky Way neighbors found that in all dwarf galaxies,
3458-419: A smaller companion galaxy—that as the two galaxy centers approach, they start to oscillate around a center point, and the oscillation creates gravitational ripples forming the shells of stars, similar to ripples spreading on water. For example, galaxy NGC 3923 has over 20 shells. Spiral galaxies resemble spiraling pinwheels . Though the stars and other visible material contained in such a galaxy lie mostly on
3591-518: A snake and raped her. Rhea became pregnant and gave birth to Persephone . Zeus in the form of a snake would mate with his daughter Persephone, which resulted in the birth of Dionysus . Zeus granted Callirrhoe's prayer that her sons by Alcmaeon , Acarnan and Amphoterus , grow quickly so that they might be able to avenge the death of their father by the hands of Phegeus and his two sons. Both Zeus and Poseidon wooed Thetis , daughter of Nereus . But when Themis (or Prometheus) prophesied that
3724-496: A thousand stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass . Most of the mass in a typical galaxy is in the form of dark matter , with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies. Galaxies are categorised according to their visual morphology as elliptical , spiral , or irregular . The Milky Way
3857-476: A tree which produces golden apples as a wedding gift. Eratosthenes and Hyginus attribute a similar story to Pherecydes, in which Hera is amazed by the gift, and asks for the apples to be planted in the "garden of the gods", nearby to Mount Atlas . Apollodorus specifies them as the golden apples of the Hesperides , and says that Gaia gives them to Zeus after the marriage. According to Diodorus Siculus ,
3990-416: A wheel that spins forever. Once, Helios the sun god gave his chariot to his inexperienced son Phaethon to drive. Phaethon could not control his father's steeds so he ended up taking the chariot too high, freezing the earth, or too low, burning everything to the ground. The earth itself prayed to Zeus, and in order to prevent further disaster, Zeus hurled a thunderbolt at Phaethon, killing him and saving
4123-430: A youthful affair between Zeus and Hera. In the Iliad , the pair are described as having first lay with each other before Cronus is sent to Tartarus, without the knowledge of their parents. A scholiast on the Iliad states that, after Cronus is banished to Tartarus, Oceanus and Tethys give Hera to Zeus in marriage, and only shortly after the two are wed, Hera gives birth to Hephaestus , having lay secretly with Zeus on
Spitzer Infrared Nearby Galaxies Survey - Misplaced Pages Continue
4256-528: Is 3C 236 , with lobes 15 million light-years across. It should however be noted that radio emissions are not always considered part of the main galaxy itself. A giant radio galaxy is a special class of objects characterized by the presence of radio lobes generated by relativistic jets powered by the central galaxy's supermassive black hole . Giant radio galaxies are different from ordinary radio galaxies in that they can extend to much larger scales, reaching upwards to several megaparsecs across, far larger than
4389-626: Is a stub . You can help Misplaced Pages by expanding it . Galaxy A galaxy is a system of stars , stellar remnants , interstellar gas , dust , and dark matter bound together by gravity . The word is derived from the Greek galaxias ( γαλαξίας ), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System . Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than
4522-516: Is a galaxy with giant regions of radio emission extending well beyond its visible structure. These energetic radio lobes are powered by jets from its active galactic nucleus . Radio galaxies are classified according to their Fanaroff–Riley classification . The FR I class have lower radio luminosity and exhibit structures which are more elongated; the FR II class are higher radio luminosity. The correlation of radio luminosity and structure suggests that
4655-562: Is also used to observe distant, red-shifted galaxies that were formed much earlier. Water vapor and carbon dioxide absorb a number of useful portions of the infrared spectrum, so high-altitude or space-based telescopes are used for infrared astronomy . The first non-visual study of galaxies, particularly active galaxies, was made using radio frequencies . The Earth's atmosphere is nearly transparent to radio between 5 MHz and 30 GHz. The ionosphere blocks signals below this range. Large radio interferometers have been used to map
4788-682: Is an ancient Greek epic poem attributed to Homer about the Trojan war and the battle over the City of Troy , in which Zeus plays a major part. Scenes in which Zeus appears include: When Hades requested to marry Zeus's daughter, Persephone , Zeus approved and advised Hades to abduct Persephone, as her mother Demeter would not allow her to marry Hades. In the Orphic "Rhapsodic Theogony" (first century BC/AD), Zeus wanted to marry his mother Rhea . After Rhea refused to marry him, Zeus turned into
4921-430: Is an example of a spiral galaxy. It is estimated that there are between 200 billion ( 2 × 10 ) to 2 trillion galaxies in the observable universe . Most galaxies are 1,000 to 100,000 parsecs in diameter (approximately 3,000 to 300,000 light years ) and are separated by distances in the order of millions of parsecs (or megaparsecs). For comparison, the Milky Way has a diameter of at least 26,800 parsecs (87,400 ly) and
5054-610: Is born in Dicte , and the mythographer Apollodorus (first or second century AD) similarly says he was born in a cave in Dicte. While the Theogony says nothing of Zeus's upbringing other than that he grew up swiftly, other sources provide more detailed accounts. According to Apollodorus, Rhea, after giving birth to Zeus in a cave in Dicte, gives him to the nymphs Adrasteia and Ida , daughters of Melisseus , to nurse. They feed him on
5187-593: Is born, emerging from Zeus's head, but the foretold son never comes forth. Apollodorus presents a similar version, stating that Metis took many forms in attempting to avoid Zeus's embraces, and that it was Gaia alone who warned Zeus of the son who would overthrow him. According to a fragment likely from the Hesiodic corpus, quoted by Chrysippus, it is out of anger at Hera for producing Hephaestus on her own that Zeus has intercourse with Metis, and then swallows her, thereby giving rise to Athena from himself. A scholiast on
5320-531: Is called the Galactic Center . The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter . Consequently, these galaxies also have
5453-476: Is given "ephemeral fruits" by the Moirai , which reduce his strength. The monster then flees to Thrace, where he hurls mountains at Zeus, which are sent back at him by the god's thunderbolts, before, while fleeing to Sicily , Zeus launches Mount Etna upon him, finally ending him. Nonnus , who gives the longest and most detailed account, presents a narrative similar to Apollodorus, with differences such as that it
Spitzer Infrared Nearby Galaxies Survey - Misplaced Pages Continue
5586-461: Is given by the Hubble sequence . Since the Hubble sequence is entirely based upon visual morphological type (shape), it may miss certain important characteristics of galaxies such as star formation rate in starburst galaxies and activity in the cores of active galaxies . Many galaxies are thought to contain a supermassive black hole at their center. This includes the Milky Way, whose core region
5719-697: Is his sister Demeter , with whom he has Persephone . Zeus's next consort is the Titan Mnemosyne ; as described at the beginning of the Theogony , Zeus lies with Mnemosyne in Piera each night for nine nights, producing the nine Muses. His sixth wife is the Titan Leto , who bears him the twins Apollo and Artemis , who, according to the Homeric Hymn to Apollo , are born on the island of Delos . In Hesiod's account, Zeus's seventh and final wife
5852-442: Is his sister Hera . While Hera is Zeus's seventh wife in Hesiod's version, in other accounts she is his first and only wife. In the Theogony , the couple has three children, Ares , Hebe , and Eileithyia . While Hesiod states that Hera produces Hephaestus on her own after Athena is born from Zeus's head, other versions, including Homer, have Hephaestus as a child of Zeus and Hera as well. Various authors give descriptions of
5985-612: Is instead Cadmus and Pan who recovers Zeus's sinews, by luring Typhon with music and then tricking him. In the Iliad , Homer tells of another attempted overthrow, in which Hera, Poseidon, and Athena conspire to overpower Zeus and tie him in bonds. It is only because of the Nereid Thetis , who summons Briareus, one of the Hecatoncheires , to Olympus, that the other Olympians abandon their plans (out of fear for Briareus). According to Hesiod, Zeus takes Metis , one of
6118-729: Is not his son. While Hesiod gives Lyctus as Zeus's birthplace, he is the only source to do so, and other authors give different locations. The poet Eumelos of Corinth (8th century BC), according to John the Lydian , considered Zeus to have been born in Lydia , while the Alexandrian poet Callimachus (c. 310 – c. 240 BC), in his Hymn to Zeus , says that he was born in Arcadia . Diodorus Siculus (fl. 1st century BC) seems at one point to give Mount Ida as his birthplace, but later states he
6251-444: Is nursing an unknown baby: she pushes the baby away, some of her milk spills, and it produces the band of light known as the Milky Way. In the astronomical literature, the capitalised word "Galaxy" is often used to refer to the Milky Way galaxy, to distinguish it from the other galaxies in the observable universe . The English term Milky Way can be traced back to a story by Geoffrey Chaucer c. 1380 : See yonder, lo,
6384-422: Is reduced to ashes. According to Callimachus, after Zeus sleeps with Callisto, Hera turns her into a bear, and instructs Artemis to shoot her. In addition, Zeus's son by Alcmene, the hero Heracles , is persecuted continuously throughout his mortal life by Hera, up until his apotheosis. According to Diodorus Siculus , Alcmene, the mother of Heracles, was the very last mortal woman Zeus ever slept with; following
6517-496: Is separated from the Andromeda Galaxy , its nearest large neighbour, by just over 750,000 parsecs (2.5 million ly). The space between galaxies is filled with a tenuous gas (the intergalactic medium ) with an average density of less than one atom per cubic metre. Most galaxies are gravitationally organised into groups , clusters and superclusters . The Milky Way is part of the Local Group , which it dominates along with
6650-417: Is sometimes referred to as a flocculent spiral galaxy ; in contrast to the grand design spiral galaxy that has prominent and well-defined spiral arms. The speed in which a galaxy rotates is thought to correlate with the flatness of the disc as some spiral galaxies have thick bulges, while others are thin and dense. In spiral galaxies, the spiral arms do have the shape of approximate logarithmic spirals ,
6783-518: The Iliad , in contrast, states that when Zeus swallows her, Metis is pregnant with Athena not by Zeus himself, but by the Cyclops Brontes. The motif of Zeus swallowing Metis can be seen as a continuation of the succession myth: it is prophesied that a son of Zeus will overthrow him, just as he overthrew his father, but whereas Cronos met his end because he did not swallow the real Zeus, Zeus holds onto his power because he successfully swallows
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#17327808626396916-601: The Andromeda Galaxy . The group is part of the Virgo Supercluster . At the largest scale , these associations are generally arranged into sheets and filaments surrounded by immense voids . Both the Local Group and the Virgo Supercluster are contained in a much larger cosmic structure named Laniakea . The word galaxy was borrowed via French and Medieval Latin from the Greek term for
7049-603: The Linear B syllabic script. Zeus is the Greek continuation of * Di̯ēus , the name of the Proto-Indo-European god of the daytime sky, also called * Dyeus ph 2 tēr ("Sky Father"). The god is known under this name in the Rigveda ( Vedic Sanskrit Dyaus/Dyaus Pita ), Latin (compare Jupiter , from Iuppiter , deriving from the Proto-Indo-European vocative * dyeu-ph 2 tēr ), deriving from
7182-461: The Oceanid daughters of Oceanus and Tethys , as his first wife. However, when she is about to give birth to a daughter, Athena , he swallows her whole upon the advice of Gaia and Uranus, as it had been foretold that after bearing a daughter, she would give birth to a son, who would overthrow him as king of gods and mortals; it is from this position that Metis gives counsel to Zeus. In time, Athena
7315-487: The Sloan Digital Sky Survey . Greek philosopher Democritus (450–370 BCE) proposed that the bright band on the night sky known as the Milky Way might consist of distant stars. Aristotle (384–322 BCE), however, believed the Milky Way was caused by "the ignition of the fiery exhalation of some stars that were large, numerous and close together" and that the "ignition takes place in the upper part of
7448-583: The University of Nottingham , used 20 years of Hubble images to estimate that the observable universe contained at least two trillion ( 2 × 10 ) galaxies. However, later observations with the New Horizons space probe from outside the zodiacal light reduced this to roughly 200 billion ( 2 × 10 ). Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance
7581-579: The atmosphere , in the region of the World that is continuous with the heavenly motions ." Neoplatonist philosopher Olympiodorus the Younger ( c. 495 –570 CE) was critical of this view, arguing that if the Milky Way was sublunary (situated between Earth and the Moon) it should appear different at different times and places on Earth, and that it should have parallax , which it did not. In his view,
7714-486: The root * dyeu - ("to shine", and in its many derivatives, "sky, heaven, god"). Albanian Zoj-z and Messapic Zis are clear equivalents and cognates of Zeus . In the Greek, Albanian, and Messapic forms the original cluster *di̯ underwent affrication to *dz . Zeus is the only deity in the Olympic pantheon whose name has such a transparent Indo-European etymology. Plato , in his Cratylus , gives
7847-603: The spectra invisible to humans (radio telescopes, infrared cameras, and x-ray telescopes ) allows detection of other galaxies that are not detected by Hubble. Particularly, surveys in the Zone of Avoidance (the region of sky blocked at visible-light wavelengths by the Milky Way) have revealed a number of new galaxies. A 2016 study published in The Astrophysical Journal , led by Christopher Conselice of
7980-517: The tutelary deity of the mountain, stops her, saying that Zeus is sleeping there with Leto. Photius , in his Bibliotheca , tells us that in Ptolemy Hephaestion 's New History , Hera refuses to lay with Zeus, and hides in a cave to avoid him, before an earthborn man named Achilles convinces her to marry Zeus, leading to the pair first sleeping with each other. According to Stephanus of Byzantium , Zeus and Hera first lay together at
8113-519: The type-cD galaxies . First described in 1964 by a paper by Thomas A. Matthews and others, they are a subtype of the more general class of D galaxies, which are giant elliptical galaxies, except that they are much larger. They are popularly known as the supergiant elliptical galaxies and constitute the largest and most luminous galaxies known. These galaxies feature a central elliptical nucleus with an extensive, faint halo of stars extending to megaparsec scales. The profile of their surface brightnesses as
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#17327808626398246-579: The "Great Andromeda Nebula", as the Andromeda Galaxy, Messier object M31 , was then known. Searching the photographic record, he found 11 more novae . Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within this galaxy. As a result, he was able to come up with a distance estimate of 150,000 parsecs . He became a proponent of the so-called "island universes" hypothesis, which holds that spiral nebulae are actually independent galaxies. In 1920
8379-525: The 1990s, the Hubble Space Telescope yielded improved observations. Among other things, its data helped establish that the missing dark matter in this galaxy could not consist solely of inherently faint and small stars. The Hubble Deep Field , an extremely long exposure of a relatively empty part of the sky, provided evidence that there are about 125 billion ( 1.25 × 10 ) galaxies in the observable universe. Improved technology in detecting
8512-550: The Galaxyë Which men clepeth the Milky Wey , For hit is whyt. Galaxies were initially discovered telescopically and were known as spiral nebulae . Most 18th- to 19th-century astronomers considered them as either unresolved star clusters or anagalactic nebulae , and were just thought of as a part of the Milky Way, but their true composition and natures remained a mystery. Observations using larger telescopes of
8645-477: The Gigantomachy. According to Hesiod, the Giants are the offspring of Gaia, born from the drops of blood that fell on the ground when Cronus castrated his father Uranus; there is, however, no mention of a battle between the gods and the Giants in the Theogony . It is Apollodorus who provides the most complete account of the Gigantomachy. He says that Gaia, out of anger at how Zeus had imprisoned her children,
8778-584: The Homeric "cloud collector" was the god of the sky and thunder like his Near-Eastern counterparts, he was also the supreme cultural artifact; in some senses, he was the embodiment of Greek religious beliefs and the archetypal Greek deity. Popular conceptions of Zeus differed widely from place to place. Local varieties of Zeus often have little in common with each other except the name. They exercised different areas of authority and were worshiped in different ways; for example, some local cults conceived of Zeus as
8911-432: The Hubble classification scheme, spiral galaxies are listed as type S , followed by a letter ( a , b , or c ) which indicates the degree of tightness of the spiral arms and the size of the central bulge. An Sa galaxy has tightly wound, poorly defined arms and possesses a relatively large core region. At the other extreme, an Sc galaxy has open, well-defined arms and a small core region. A galaxy with poorly defined arms
9044-498: The Hundred-Handers attack with barrages of rocks, and the Titans are finally defeated, with Zeus banishing them to Tartarus and assigning the Hundred-Handers the task of acting as their warders. Apollodorus provides a similar account, saying that, when Zeus reaches adulthood, he enlists the help of the Oceanid Metis , who gives Cronus an emetic , forcing to him to disgorge the stone and Zeus's five siblings. Zeus then fights
9177-462: The Milky Way galaxy was "a myriad of tiny stars packed together in the sphere of the fixed stars." Actual proof of the Milky Way consisting of many stars came in 1610 when the Italian astronomer Galileo Galilei used a telescope to study it and discovered it was composed of a huge number of faint stars. In 1750, English astronomer Thomas Wright , in his An Original Theory or New Hypothesis of
9310-431: The Milky Way was a flattened disk of stars, and that some of the nebulae visible in the night sky might be separate Milky Ways. Toward the end of the 18th century, Charles Messier compiled a catalog containing the 109 brightest celestial objects having nebulous appearance. Subsequently, William Herschel assembled a catalog of 5,000 nebulae. In 1845, Lord Rosse examined the nebulae catalogued by Herschel and observed
9443-493: The Milky Way was celestial. According to Mohani Mohamed, Arabian astronomer Ibn al-Haytham (965–1037) made the first attempt at observing and measuring the Milky Way's parallax, and he thus "determined that because the Milky Way had no parallax, it must be remote from the Earth, not belonging to the atmosphere." Persian astronomer al-Biruni (973–1048) proposed the Milky Way galaxy was "a collection of countless fragments of
9576-405: The Milky Way, galaxías (kúklos) γαλαξίας ( κύκλος ) 'milky (circle)', named after its appearance as a milky band of light in the sky. In Greek mythology , Zeus places his son, born by a mortal woman, the infant Heracles , on Hera 's breast while she is asleep so the baby will drink her divine milk and thus become immortal. Hera wakes up while breastfeeding and then realises she
9709-481: The Milky Way. Despite the prominence of large elliptical and spiral galaxies, most galaxies are dwarf galaxies. They are relatively small when compared with other galactic formations, being about one hundredth the size of the Milky Way, with only a few billion stars. Blue compact dwarf galaxies contains large clusters of young, hot, massive stars . Ultra-compact dwarf galaxies have been discovered that are only 100 parsecs across. Many dwarf galaxies may orbit
9842-402: The Milky Way. In 1926 Hubble produced a classification of galactic morphology that is used to this day. Advances in astronomy have always been driven by technology. After centuries of success in optical astronomy , infrared astronomy was attempted in the 1830s, but only blossomed in the early 1900s. Radio astronomy was born in the 1930s, and matured by the 1950s and 1960s. The problem
9975-439: The Titans and banishes them to Tartarus, his rule is challenged by the monster Typhon , a giant serpentine creature who battles Zeus for control of the cosmos. According to Hesiod, Typhon is the offspring of Gaia and Tartarus , described as having a hundred snaky fire-breathing heads. Hesiod says he "would have come to reign over mortals and immortals" had it not been for Zeus noticing the monster and dispatching with him quickly:
10108-560: The Titans fighting from Mount Othrys . The battle lasts for ten years with no clear victor emerging, until, upon Gaia's advice, Zeus releases the Hundred-Handers , who (similarly to the Cyclopes) were imprisoned beneath the Earth's surface. He gives them nectar and ambrosia and revives their spirits, and they agree to aid him in the war. Zeus then launches his final attack on the Titans, hurling bolts of lightning upon them while
10241-518: The Titans, Zeus shares the world with his brothers, Poseidon and Hades, by drawing lots: Zeus receives the sky, Poseidon the sea, and Hades the underworld, with the earth and Olympus remaining common ground. Upon assuming his place as king of the cosmos, Zeus's rule is quickly challenged. The first of these challenges to his power comes from the Giants , who fight the Olympian gods in a battle known as
10374-406: The Titans, bore the Giants to Uranus. There comes to the gods a prophecy that the Giants cannot be defeated by the gods on their own, but can be defeated only with the help of a mortal; Gaia, upon hearing of this, seeks a special pharmakon (herb) that will prevent the Giants from being killed. Zeus, however, orders Eos (Dawn), Selene (Moon) and Helios (Sun) to stop shining, and harvests all of
10507-648: The UGC ( Uppsala General Catalogue of Galaxies), and the PGC ( Catalogue of Principal Galaxies , also known as LEDA). All the well-known galaxies appear in one or more of these catalogues but each time under a different number. For example, Messier 109 (or "M109") is a spiral galaxy having the number 109 in the catalogue of Messier. It also has the designations NGC 3992, UGC 6937, CGCG 269–023, MCG +09-20-044, and PGC 37617 (or LEDA 37617), among others. Millions of fainter galaxies are known by their identifiers in sky surveys such as
10640-483: The Universe , correctly speculated that it might be a rotating body of a huge number of stars held together by gravitational forces, akin to the Solar System but on a much larger scale, and that the resulting disk of stars could be seen as a band on the sky from a perspective inside it. In his 1755 treatise, Immanuel Kant elaborated on Wright's idea about the Milky Way's structure. The first project to describe
10773-407: The active jets emitted from active nuclei. Ultraviolet and X-ray telescopes can observe highly energetic galactic phenomena. Ultraviolet flares are sometimes observed when a star in a distant galaxy is torn apart from the tidal forces of a nearby black hole. The distribution of hot gas in galactic clusters can be mapped by X-rays. The existence of supermassive black holes at the cores of galaxies
10906-412: The better portions. He sacrificed a large ox , and divided it into two piles. In one pile he put all the meat and most of the fat, covering it with the ox's grotesque stomach, while in the other pile, he dressed up the bones with fat. Prometheus then invited Zeus to choose; Zeus chose the pile of bones. This set a precedent for sacrifices, where humans will keep the fat for themselves and burn the bones for
11039-449: The birth of Heracles, he ceased to beget humans altogether, and fathered no more children. The following is a list of Zeus's offspring, by various mothers. Beside each offspring, the earliest source to record the parentage is given, along with the century to which the source dates. When the gods met at Mecone to discuss which portions they will receive after a sacrifice, the titan Prometheus decided to trick Zeus so that humans receive
11172-428: The bridal clothing; she is so relieved that the couple are reconciled. According to a version from Plutarch, as recorded by Eusebius in his Praeparatio evangelica , when Hera is angry with her husband, she retreats instead to Cithaeron, and Zeus goes to the earth-born man Alalcomeneus, who suggests he pretend to marry someone else. With the help of Alalcomeneus, Zeus creates a wooden statue from an oak tree, dresses it as
11305-474: The cause of life (zen). While Lactantius wrote that he was called Zeus and Zen, not because he is the giver of life, but because he was the first who lived of the children of Cronus . Zeus was called by numerous alternative names or surnames, known as epithets . Some epithets are the surviving names of local gods who were consolidated into the myth of Zeus. In Hesiod 's Theogony (c. 730 – 700 BC), Cronus , after castrating his father Uranus , becomes
11438-498: The center. A different method by Harlow Shapley based on the cataloguing of globular clusters led to a radically different picture: a flat disk with diameter approximately 70 kiloparsecs and the Sun far from the centre. Both analyses failed to take into account the absorption of light by interstellar dust present in the galactic plane ; but after Robert Julius Trumpler quantified this effect in 1930 by studying open clusters ,
11571-749: The central mass is approximately 10 million solar masses , regardless of whether it has thousands or millions of stars. This suggests that galaxies are largely formed by dark matter , and that the minimum size may indicate a form of warm dark matter incapable of gravitational coalescence on a smaller scale. Interactions between galaxies are relatively frequent, and they can play an important role in galactic evolution . Near misses between galaxies result in warping distortions due to tidal interactions , and may cause some exchange of gas and dust. Collisions occur when two galaxies pass directly through each other and have sufficient relative momentum not to merge. The stars of interacting galaxies usually do not collide, but
11704-424: The city of Hermione , having come there from Crete. Callimachus, in a fragment from his Aetia , also apparently makes reference to the couple's union occurring at Naxos . Though no complete account of Zeus and Hera's wedding exists, various authors make reference to it. According to a scholiast on Apollonius of Rhodes ' Argonautica , Pherecydes states that when Zeus and Hera are being married, Gaia brings
11837-442: The core, or else due to a tidal interaction with another galaxy. Many barred spiral galaxies are active, possibly as a result of gas being channeled into the core along the arms. Our own galaxy, the Milky Way , is a large disk-shaped barred-spiral galaxy about 30 kiloparsecs in diameter and a kiloparsec thick. It contains about two hundred billion (2×10 ) stars and has a total mass of about six hundred billion (6×10 ) times
11970-399: The core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB , followed by a lower-case letter ( a , b or c ) which indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies). Bars are thought to be temporary structures that can occur as a result of a density wave radiating outward from
12103-558: The cultures of the ancient Near East , such as the scepter . The god's name in the nominative is Ζεύς ( Zeús ). It is inflected as follows: vocative : Ζεῦ ( Zeû ); accusative : Δία ( Día ); genitive : Διός ( Diós ); dative : Διί ( Dií ). Diogenes Laërtius quotes Pherecydes of Syros as spelling the name Ζάς . The earliest attested forms of the name are the Mycenaean Greek 𐀇𐀸 , di-we (dative) and 𐀇𐀺 , di-wo (genitive), written in
12236-434: The diameters of their host galaxies. Zeus Zeus ( / zj uː s / , Ancient Greek : Ζεύς ) is the sky and thunder god in ancient Greek religion and mythology , who rules as king of the gods on Mount Olympus . His name is cognate with the first syllable of his Roman equivalent Jupiter . Zeus is the child of Cronus and Rhea , the youngest of his siblings to be born, though sometimes reckoned
12369-479: The eldest as the others required disgorging from Cronus's stomach. In most traditions, he is married to Hera , by whom he is usually said to have fathered Ares , Eileithyia , Hebe , and Hephaestus . At the oracle of Dodona , his consort was said to be Dione , by whom the Iliad states that he fathered Aphrodite . According to the Theogony , Zeus's first wife was Metis , by whom he had Athena . Zeus
12502-400: The formation of fossil groups or fossil clusters, where a large, relatively isolated, supergiant elliptical resides in the middle of the cluster and are surrounded by an extensive cloud of X-rays as the residue of these galactic collisions. Another older model posits the phenomenon of cooling flow , where the heated gases in clusters collapses towards their centers as they cool, forming stars in
12635-590: The galaxies' original morphology. If one of the galaxies is much more massive than the other, the result is known as cannibalism , where the more massive larger galaxy remains relatively undisturbed, and the smaller one is torn apart. The Milky Way galaxy is currently in the process of cannibalizing the Sagittarius Dwarf Elliptical Galaxy and the Canis Major Dwarf Galaxy . Stars are created within galaxies from
12768-448: The gas and dust within the two forms interacts, sometimes triggering star formation. A collision can severely distort the galaxies' shapes, forming bars, rings or tail-like structures. At the extreme of interactions are galactic mergers, where the galaxies' relative momentums are insufficient to allow them to pass through each other. Instead, they gradually merge to form a single, larger galaxy. Mergers can result in significant changes to
12901-571: The goat Amalthea. He also refers to the Kouretes "rais[ing] a great alarum", and in doing so deceiving Cronus, and relates that when the Kouretes were carrying the newborn Zeus that the umbilical cord fell away at the river Triton. Hyginus , in his Fabulae , relates a version in which Cronus casts Poseidon into the sea and Hades to the Underworld instead of swallowing them. When Zeus is born, Hera (also not swallowed), asks Rhea to give her
13034-416: The gods rise in his presence." He was equated with many foreign weather gods , permitting Pausanias to observe "That Zeus is king in heaven is a saying common to all men". Zeus's symbols are the thunderbolt , eagle , bull , and oak . In addition to his Indo-European inheritance , the classical "cloud-gatherer" ( Greek : Νεφεληγερέτα , Nephelēgereta ) also derives certain iconographic traits from
13167-453: The gods. Zeus, enraged at Prometheus's deception, prohibited the use of fire by humans. Prometheus, however, stole fire from Olympus in a fennel stalk and gave it to humans. This further enraged Zeus, who punished Prometheus by binding him to a cliff, where an eagle constantly ate Prometheus's liver, which regenerated every night. Prometheus was eventually freed from his misery by Heracles . Now Zeus, angry at humans, decides to give humanity
13300-409: The herb himself, before having Athena summon Heracles . In the conflict, Porphyrion , one of the most powerful of the Giants, launches an attack upon Heracles and Hera; Zeus, however, causes Porphyrion to become lustful for Hera, and when he is just about to violate her, Zeus strikes him with his thunderbolt, before Heracles deals the fatal blow with an arrow. In the Theogony , after Zeus defeats
13433-470: The higher density. (The velocity returns to normal after the stars depart on the other side of the arm.) This effect is akin to a "wave" of slowdowns moving along a highway full of moving cars. The arms are visible because the high density facilitates star formation, and therefore they harbor many bright and young stars. A majority of spiral galaxies, including the Milky Way galaxy, have a linear, bar-shaped band of stars that extends outward to either side of
13566-443: The intervention of the Moirai and Themis ; he instead transforms them into various species of birds. According to the Theogony , after Zeus reaches manhood, Cronus is made to disgorge the five children and the stone "by the stratagems of Gaia, but also by the skills and strength of Zeus", presumably in reverse order, vomiting out the stone first, then each of the five children in the opposite order to swallowing. Zeus then sets up
13699-459: The island of Samos beforehand; to conceal this act, she claimed that she had produced Hephaestus on her own. According to another scholiast on the Iliad , Callimachus , in his Aetia , says that Zeus lay with Hera for three hundred years on the island of Samos. According to a scholion on Theocritus ' Idylls , Zeus, one day seeing Hera walking apart from the other gods, becomes intent on having intercourse with her, and transforms himself into
13832-431: The jar and released all the evils, which made mankind miserable. Only hope remained inside the jar. When Zeus was atop Mount Olympus he was appalled by human sacrifice and other signs of human decadence. He decided to wipe out mankind and flooded the world with the help of his brother Poseidon . After the flood, only Deucalion and Pyrrha remained. This flood narrative is a common motif in mythology. The Iliad
13965-474: The lap of Leda , subsequently seducing her, while in Euripides's lost play Antiope , Zeus apparently took the form of a satyr to sleep with Antiope . Various authors speak of Zeus raping Callisto , one of the companions of Artemis , doing so in the form of Artemis herself according to Ovid (or, as mentioned by Apollodorus, in the form of Apollo ), and Pherecydes relates that Zeus sleeps with Alcmene ,
14098-460: The location of the marriage is in the land of the Knossians , nearby to the river Theren, while Lactantius attributes to Varro the statement that the couple are married on the island of Samos. There exist several stories in which Zeus, receiving advice, is able to reconcile with an angered Hera. According to Pausanias, Hera, angry with her husband, retreats to the island of Euboea, where she
14231-421: The mass of the Sun. Recently, researchers described galaxies called super-luminous spirals. They are very large with an upward diameter of 437,000 light-years (compared to the Milky Way's 87,400 light-year diameter). With a mass of 340 billion solar masses, they generate a significant amount of ultraviolet and mid-infrared light. They are thought to have an increased star formation rate around 30 times faster than
14364-467: The milk of the she-goat Amalthea , while the Kouretes guard the cave and beat their spears on their shields so that Cronus cannot hear the infant's crying. Diodorus Siculus provides a similar account, saying that, after giving birth, Rhea travels to Mount Ida and gives the newborn Zeus to the Kouretes, who then takes him to some nymphs (not named), who raised him on a mixture of honey and milk from
14497-520: The monster a chance to wrap him in his coils, and rip out the sinews from his hands and feet. Disabled, Zeus is taken by Typhon to the Corycian Cave in Cilicia, where he is guarded by the "she-dragon" Delphyne . Hermes and Aegipan , however, steal back Zeus's sinews, and refit them, reviving him and allowing him to return to the battle, pursuing Typhon, who flees to Mount Nysa; there, Typhon
14630-446: The nature of nebulous stars." Andalusian astronomer Avempace ( d. 1138) proposed that it was composed of many stars that almost touched one another, and appeared to be a continuous image due to the effect of refraction from sublunary material, citing his observation of the conjunction of Jupiter and Mars as evidence of this occurring when two objects were near. In the 14th century, Syrian-born Ibn Qayyim al-Jawziyya proposed
14763-401: The nurses of Zeus. According to a fragment of Epimenides, the nymphs Helike and Kynosura are the young Zeus's nurses. Cronus travels to Crete to look for Zeus, who, to conceal his presence, transforms himself into a snake and his two nurses into bears. According to Musaeus , after Zeus is born, Rhea gives him to Themis . Themis in turn gives him to Amalthea, who owns a she-goat, which nurses
14896-472: The present picture of the Milky Way galaxy emerged. A few galaxies outside the Milky Way are visible on a dark night to the unaided eye , including the Andromeda Galaxy , Large Magellanic Cloud , Small Magellanic Cloud , and the Triangulum Galaxy . In the 10th century, Persian astronomer Abd al-Rahman al-Sufi made the earliest recorded identification of the Andromeda Galaxy, describing it as
15029-474: The process, a phenomenon observed in clusters such as Perseus , and more recently in the Phoenix Cluster . A shell galaxy is a type of elliptical galaxy where the stars in its halo are arranged in concentric shells. About one-tenth of elliptical galaxies have a shell-like structure, which has never been observed in spiral galaxies. These structures are thought to develop when a larger galaxy absorbs
15162-424: The request of Apollo's mother, Leto , Zeus instead ordered Apollo to serve as a slave to King Admetus of Pherae for a year. According to Diodorus Siculus , Zeus killed Asclepius because of complains from Hades, who was worried that the number of people in the underworld was diminishing because of Asclepius's resurrections. The winged horse Pegasus carried the thunderbolts of Zeus. Zeus took pity on Ixion ,
15295-475: The shape of the Milky Way and the position of the Sun was undertaken by William Herschel in 1785 by counting the number of stars in different regions of the sky. He produced a diagram of the shape of the galaxy with the Solar System close to the center . Using a refined approach, Kapteyn in 1920 arrived at the picture of a small (diameter about 15 kiloparsecs) ellipsoid galaxy with the Sun close to
15428-543: The son born of Thetis would be mightier than his father, Thetis was married off to the mortal Peleus . Zeus was afraid that his grandson Asclepius would teach resurrection to humans, so he killed Asclepius with his thunderbolt. This angered Asclepius's father, Apollo , who in turn killed the Cyclopes who had fashioned the thunderbolts of Zeus. Angered at this, Zeus would have imprisoned Apollo in Tartarus. However, at
15561-439: The sources in these two types of galaxies may differ. Radio galaxies can also be classified as giant radio galaxies (GRGs), whose radio emissions can extend to scales of megaparsecs (3.26 million light-years). Alcyoneus is an FR II class low-excitation radio galaxy which has the largest observed radio emission, with lobed structures spanning 5 megaparsecs (16×10 ly ). For comparison, another similarly sized giant radio galaxy
15694-576: The spiral structure of Messier object M51 , now known as the Whirlpool Galaxy. In 1912, Vesto M. Slipher made spectrographic studies of the brightest spiral nebulae to determine their composition. Slipher discovered that the spiral nebulae have high Doppler shifts , indicating that they are moving at a rate exceeding the velocity of the stars he had measured. He found that the majority of these nebulae are moving away from us. In 1917, Heber Doust Curtis observed nova S Andromedae within
15827-547: The stone at Delphi , so that it may act as "a sign thenceforth and a marvel to mortal men". Zeus next frees the Cyclopes , who, in return, and out of gratitude, give him his thunderbolt, which had previously been hidden by Gaia. Then begins the Titanomachy , the war between the Olympians, led by Zeus, and the Titans, led by Cronus, for control of the universe, with Zeus and the Olympians fighting from Mount Olympus , and
15960-564: The supreme ruler of the cosmos, and weds his sister Rhea , by whom he begets three daughters and three sons: Hestia , Demeter , Hera , Hades , Poseidon , and lastly, "wise" Zeus, the youngest of the six. He swallows each child as soon as they are born, having received a prophecy from his parents, Gaia and Uranus, that one of his own children is destined to one day overthrow him as he overthrew his father. This causes Rhea "unceasing grief", and upon becoming pregnant with her sixth child, Zeus, she approaches her parents, Gaia and Uranus, seeking
16093-505: The threat, in the form of the potential mother, and so the "cycle of displacement" is brought to an end. In addition, the myth can be seen as an allegory for Zeus gaining the wisdom of Metis for himself by swallowing her. In Hesiod's account, Zeus's second wife is Themis , one of the Titan daughters of Uranus and Gaia, with whom he has the Horae , listed as Eunomia , Dike and Eirene , and
16226-609: The three Moirai : Clotho , Lachesis and Atropos . A fragment from Pindar calls Themis Zeus's first wife, and states that she is brought by the Moirai (in this version not her daughters) up to Olympus, where she becomes the bride of Zeus and bears him the Horae. According to Hesiod, Zeus next marries the Oceanid Eurynome , with whom he has the three Charites , namely Aglaea , Euphrosyne and Thalia . Zeus's fourth wife
16359-511: The two of them meet in a cataclysmic battle, before Zeus defeats him easily with his thunderbolt, and the creature is hurled down to Tartarus. Epimenides presents a different version, in which Typhon makes his way into Zeus's palace while he is sleeping, only for Zeus to wake and kill the monster with a thunderbolt. Aeschylus and Pindar give somewhat similar accounts to Hesiod, in that Zeus overcomes Typhon with relative ease, defeating him with his thunderbolt. Apollodorus, in contrast, provides
16492-498: The universe that extended far beyond what could be seen. These views "are remarkably close to the present-day views of the cosmos." In 1745, Pierre Louis Maupertuis conjectured that some nebula -like objects were collections of stars with unique properties, including a glow exceeding the light its stars produced on their own, and repeated Johannes Hevelius 's view that the bright spots were massive and flattened due to their rotation. In 1750, Thomas Wright correctly speculated that
16625-442: The universe's early history, but still contribute an estimated 15% to total star production. Starburst galaxies are characterized by dusty concentrations of gas and the appearance of newly formed stars, including massive stars that ionize the surrounding clouds to create H II regions . These stars produce supernova explosions, creating expanding remnants that interact powerfully with the surrounding gas. These outbursts trigger
16758-530: The wife of Amphitryon , in the form of her own husband. Several accounts state that Zeus approached the Argive princess Danae in the form of a shower of gold, and according to Ovid he abducts Aegina in the form of a flame. In accounts of Zeus's affairs, Hera is often depicted as a jealous wife, with there being various stories of her persecuting either the women with whom Zeus sleeps, or their children by him. Several authors relate that Zeus sleeps with Io ,
16891-558: The world from further harm. In a satirical work, Dialogues of the Gods by Lucian , Zeus berates Helios for allowing such thing to happen; he returns the damaged chariot to him and warns him that if he dares do that again, he will strike him with one of this thunderbolts. Zeus played a dominant role, presiding over the Greek Olympian pantheon. He fathered many of the heroes and was featured in many of their local cults . Though
17024-406: The young Zeus, and Rhea gives Cronus a stone to swallow. Hera gives him to Amalthea, who hangs his cradle from a tree, where he is not in heaven, on earth or in the sea, meaning that when Cronus later goes looking for Zeus, he is unable to find him. Hyginus also says that Ida , Althaea, and Adrasteia , usually considered the children of Oceanus , are sometimes called the daughters of Melisseus and
17157-518: The young Zeus. Antoninus Liberalis , in his Metamorphoses , says that Rhea gives birth to Zeus in a sacred cave in Crete, full of sacred bees, which become the nurses of the infant. While the cave is considered forbidden ground for both mortals and gods, a group of thieves seek to steal honey from it. Upon laying eyes on the swaddling clothes of Zeus, their bronze armour "split[s] away from their bodies", and Zeus would have killed them had it not been for
17290-458: Was also infamous for his erotic escapades. These resulted in many divine and heroic offspring, including Apollo , Artemis , Hermes , Persephone , Dionysus , Perseus , Heracles , Helen of Troy , Minos , and the Muses . He was respected as a sky father who was chief of the gods and assigned roles to the others: "Even the gods who are not his natural children address him as Father, and all
17423-405: Was confirmed through X-ray astronomy. In 1944, Hendrik van de Hulst predicted that microwave radiation with wavelength of 21 cm would be detectable from interstellar atomic hydrogen gas; and in 1951 it was observed. This radiation is not affected by dust absorption, and so its Doppler shift can be used to map the motion of the gas in this galaxy. These observations led to the hypothesis of
17556-402: Was raised, and Zeus, unable to resolve the situation, seeks the advice of Cithaeron, ruler of Plataea , supposedly the most intelligent man on earth. Cithaeron instructs him to fashion a wooden statue and dress it as a bride, and then pretend that he is marrying one "Plataea", a daughter of Asopus . When Hera hears of this, she immediately rushes there, only to discover the ruse upon ripping away
17689-493: Was that air only allows visible light and radio waves to pass, with a little bit of near infrared. The first ultraviolet telescope was launched in 1968, and since then there's been major progress in all regions of the electromagnetic spectrum . The dust present in the interstellar medium is opaque to visual light. It is more transparent to far-infrared , which can be used to observe the interior regions of giant molecular clouds and galactic cores in great detail. Infrared
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