The Boreads ( Ancient Greek : Βορεάδαι , romanized : Boreádai ) are the "wind brothers" in Greek mythology . They consist of Zetes (also Zethes ) ( Ancient Greek : Ζήτης ) and Calaïs ( Ancient Greek : Κάλαϊς ). Their place of origin was Thrace , home of their father Boreas (North wind).
69-458: Zetes and Calais were credited with very delicate and graceful hair, which was said to give them the ability to fly (though in some tales they have wings ). They had great pride in who had the longest curls between the two of them and by boasting about these locks, they were uplifted. They had dusky wings which gleamed with golden scales. The Boreads were the twin sons of Boreas and Oreithyia , daughter of King Erechtheus of Athens . They were
138-408: A deep-seated respect for anyone named Jason (because of their role as Argonauts ); and carry jagged bronze swords . The two assist their sister Khione in her bid for power, but do not ultimately ally themselves with Gaea . Wings A wing is a type of fin that produces both lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and
207-605: A double shrine of "Ge-Kourotrophos" and "Demeter-Chloe" on the Acropolis. Near the Olympieion of Athens there was the temenos of Ge-Olympia. Thucydides mentions that it was among the oldest sanctuaries built in Athens, where the Deucalion flood took place. A chthonic ritual was performed in Athens in honour of Ge. The Genesia was a mourning festival in the month Broedromion. A sacrifice
276-526: A gift. It is said that he gave to Poseidon Calaureia , that lies off Troezen , in exchange for his oracle. Apollo is the best-known as the oracle power behind Delphi, long established by the time of Homer, having killed Gaia's child Python there and usurped the chthonic power. Hera punished Apollo for this by sending him to King Admetus as a shepherd for nine years. Gaia or Ge had at least three sanctuaries in Greece which were mentioned by Pausanias . There
345-708: A particularly vital role in the rescue of Phineus from the harpies . They succeeded in driving the monsters away but did not kill them, at a request from the goddess of the rainbow, Iris , who promised that Phineas would not be bothered by the harpies again. As thanks, Phineas told the Argonauts how to pass the Symplegades . It is said that the Boreads were turned back by Iris at the Strophades . The islands' name, meaning "Islands of Turning", refers to this event. Calais in one tradition
414-405: A planform. Wing efficiency is expressed as lift-to-drag ratio , which compares the benefit of lift with the air resistance of a given wing shape, as it flies. Aerodynamics is the study of wing performance in air. Equivalent foils that move through water are found on hydrofoil power vessels and foiling sailboats that lift out of the water and on submarines that use diving planes to point
483-480: A positive angle of attack to deflect air downward. Symmetrical airfoils have higher stalling speeds than cambered airfoils of the same wing area but are used in aerobatic aircraft as they provide the same flight characteristics whether the aircraft is upright or inverted. Another example comes from sailboats, where the sail is a thin sheet. For flight speeds near the speed of sound ( transonic flight ), specific asymmetrical airfoil sections are used to minimize
552-447: A premilinary offering among other gods. Ge was associated with the dead at Mykonos. Seven black lambs were offered to "Zeus Chthonios" and "Ge-Chthonia" in the month Lenaion. The worshippers were offered to feast at the place of worship. At Sparta Gaia was worshipped together with Zeus. There was a double shrine of "Ge" and "Zeus Agoraios" (of the market place). Gaia has several epithets and attributes. In poetry chthon frequently has
621-430: A reward, for Athena's sake. Gaia also turned the young Libanus into rosemary when he was killed by impious people. Zeus hid Elara , one of his lovers, from Hera by stowing her under the earth. His son by Elara, the giant Tityos , is therefore sometimes said to be a son of Gaia, the earth goddess. Gaia also made Aristaeus immortal. It seems that the worship of the "earth" was indigenous in Greece. However it
690-485: A sacred well was used for predicting the cause of diseases. At Athens Ge acquired the cult-title Themis . Themis was an oracular goddess related to Ge and she was not originally interpreted as goddess of righteousness. The cult of Gaia was probably indigenous in Attica. In the cult of Phlya , Pausanias reports that there were altars to Dionysos, certain nymphs and to Ge, whom they called the "great goddess". The Great goddess
759-569: A similar myth, in which Aphrodite fled from her lustful father Zeus , who was infatuated with her. As Zeus was unable to catch Aphrodite, he gave up and dropped his semen on the ground, which impregnated Gaia. This resulted in the birth of the Cyprian Centaurs . Gaia resented the way Zeus had treated her children, the Titans , so she brought forth the Gigantes to fight Zeus. It was prophesied that
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#1732848723785828-411: A suitable angle of attack relative to the flow of air past the wing. When this occurs, the wing deflects the airflow downwards, "turning" the air as it passes the wing. Since the wing exerts a force on the air to change its direction, the air must exert a force on the wing, equal in size but opposite in direction. This force arises from different air pressures that exist on the upper and lower surfaces of
897-490: Is a mostly epic, collateral form of Attic Γῆ ( Gē [ɡɛ̂ː] ), and Doric Γᾶ ( Ga [ɡâː] ), perhaps identical to Δᾶ ( Da [dâː] ), both meaning " Earth ". Some scholars believe that the word is of uncertain origin. Beekes suggested a probable Pre-Greek origin. M.L.West derives the name from the Indo-European from *dʰéǵʰōm (earth). Greek : gaia (<*gm-ya), chamai (χαμαί) on
966-524: Is a speculation and controversial in the academic community. Some modern mythographers, including Kerenyi , Ruck , and Staples , interpret the goddesses Demeter the "mother", Persephone the "daughter", and Hecate the "crone", as aspects of a former great goddess identified by some as Rhea or as Gaia herself. In Crete , a goddess was worshipped as Potnia Theron (the "Mistress of the Animals") or simply Potnia ("Mistress"), speculated as Rhea or Gaia;
1035-495: Is called "pammе̄tōr", the all-mother who nourishes everything. This conception is closer to the popular belief. In the hymn to Apollo she is called "pheresvios" (life giving) The "mother of the gods" is a form of Gaia. According to Pausanias an epithet of Ge in Athens is "the Great goddess", which is an appellation of the "Mother of the gods". She is related to the mystery cult of Phlya which seems to be original. At Athens Gaia had
1104-522: Is doubtful if the mother-religion is rooted to the Pre-Greek population. In classical times Ge was not an important deity and she didn't have any festivals. She was usually honoured together with other gods or goddesses. Local cults of Gaia are rare and only some of them can be mentioned from the existing evidence. Elements of a primitive cult of Gaia appear at Dodona in Epirus. It seems that in an old religion
1173-495: Is drinking bull's blood. Any woman who may chance not to speak the truth is immediately punished as a result of this test. If several women compete for the priesthood, lots are cast for the honor. Pausanias also mention the sanctuary of Ge Gasepton in Sparta , and a sanctuary of Ge Kourotrophe (Nurse of the Young) at Athens. Aside from her temples, Gaia had altars as well as sacred spaces in
1242-593: Is early mentioned in the Catalogue of ships . He is born by the Homeric earth which produces fruits and cereals (zeidoros arura ). The name of Erichthonius includes chthon which is not the underground kingdom of the dead, but the Homeric earth. In ancient times the earth was considered a plane or a flat disk with a wide extent. The earth-goddess can be identified with the nymph "Plataia" (broad one) in Plataea of Boeotia as
1311-533: Is interpreted as "Mother of the gods" who is a form of Gaia. It seems that a mystery-cult was related to the Great-goddess. An inscription on the Acropolis of Athens refers to the practice of service in honour of "Ge-Karpophoros" (bringer of fruits) in accordance with the oracle. The oracle was probably Delphic. A sanctuary on the Acropolis was the "Kourotrophion", and the earlier inscriptions mentions simply "The Kourotrophos" (nourisher of children). Pausanias mentions
1380-462: Is said to be the beloved of Orpheus ; Orpheus was said to have been killed at the hands of jealous Thracian women whilst he wandered the countryside thinking of Calais. Their death was said to be caused by Heracles on Tenos in revenge for when they convinced the Argonauts to leave him behind as he searched for Hylas in Mysia . Other sources imply that the sons of Boreas died chasing the harpies, as it
1449-484: Is the mother mother of all ("pammetor") and in a fragment of Euripides chthon has the same epithet. In Persai of Aeschylus offerings are recommended to Ge and the spirit of the departed. She is called "pamphoros", (all bearing). In Choephori , Electra in her prayer describes Gaia as an avenger of wrong. Sophocles in Philoctetes calls Gaia "pamvōtis" (all nourishing) A famous fragment of Danaides describes
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#17328487237851518-704: Is the personification of Earth . Gaia is the ancestral mother—sometimes parthenogenic —of all life. She is the mother of Uranus (Sky), from whose sexual union she bore the Titans (themselves parents of many of the Olympian gods ), the Cyclopes , and the Giants , as well as of Pontus (Sea), from whose union she bore the primordial sea gods . Her equivalent in the Roman pantheon was Terra . The Greek name Γαῖα ( Gaia Ancient Greek : [ɡâi̯.a] or [ɡâj.ja] )
1587-512: The Homeric poems she appears usually in forms of oath. In Iliad the sacrifice of a black lamb is offered to Gaia and she is invoked in the formula of an oath. Homer considers her a physical distinct existence not clearly conceived in anthropomorphic form. Gaia does not seem to have any personal activity. In Iliad Alpheia beats with her hands the bountiful ("polyphorbos") earth, but she calls Hades and Persephone to avenge her against her son In
1656-439: The Titans , as Hesiod tells it: She lay with Heaven and bore deep-swirling Oceanus , Coeus and Crius and Hyperion and Iapetus , Theia and Rhea , Themis , and Mnemosyne and gold-crowned Phoebe and lovely Tethys . After them was born Cronos ( Cronus ) the wily, youngest, and most terrible of her children, and he hated his lusty sire. According to Hesiod, Gaia conceived further offspring with her son, Uranus, first
1725-460: The Gigantes, who were born from Uranus's blood, could not be killed by the gods alone, but they could be killed with the help of a mortal. Hearing this, Gaia sought for a certain plant that would protect the Gigantes even from mortals. Before Gaia or anyone else could get it, Zeus forbade Eos (Dawn), Selene (Moon) and Helios (Sun) to shine, harvested all of the plant himself, and had Athena summon
1794-611: The Titans, Briareus, Gyges, Steropes, Atlas, Hyperion, Polus, Saturn , Ops , Moneta , Dione, and the Furies ( Alecto , Megaera , and Tisiphone ). By Tartarus, Terra then becomes the mother of the Giants, which are listed as Enceladus , Coeus, Ophion , Astraeus , Pelorus, Pallas, Emphytus, Rhoecus, Ienios, Agrius, Palaemon, Ephialtes , Eurytus, Theomises, Theodamas, Otos, Typhon, Polybotes, Menephiarus, Abseus, Colophomus, and Iapetus. According to
1863-766: The Titans. But afterwards, Gaia, in union with Tartarus , bore the youngest of her sons Typhon , who would be the last challenge to the authority of Zeus. According to the Roman mythographer Hyginus , Terra (Earth, the Roman equivalent of Gaia), Caelus (Sky, the Roman equivalent of Uranus) and Mare (Sea) are the children of Aether and Dies (Day, the Roman equivalent of Hemera ). With Aether, Terra produces Dolor (Pain), Dolus (Deception), Ira (Anger), Luctus (Mourning), Mendacium (Lying), Iusiurandum (Oath), Vltio (Vengeance), Intemperantia (Self-indulgence), Altercatio (Quarreling), Oblivio (Forgetfulness), Socordia (Sloth), Timor (Fear), Superbia (Arrogance), Incestum (Incest), Pugna (Fighting), Oceanus (Ocean), Themis, Tartarus, Pontus,
1932-439: The airfoil on a race car . In nature wings have evolved in dinosaurs, birds , mammals, fish, reptiles and plants as means of locomotion . Various species of penguins and other flighted or flightless water birds such as auks , cormorants , guillemots , shearwaters , eider and scoter ducks and diving petrels are efficient underwater swimmers, and use their wings to propel through water. The design and analysis of
2001-496: The boat upwards or downwards, while submerged. Hydrodynamics is the study of foil performance in water. The word "wing" from the Old Norse vængr for many centuries referred mainly to the foremost limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning has extended to include lift producing appendages of insects , bats , pterosaurs , boomerangs , some sail boats and aircraft , or
2070-466: The broad-bossomed), is mentioned at Delphi by Mnaseas . A temple of Ge was built to the south of the temple of Apollo . "Eutysternos" is a surname of Ge and it had an earlier use by Hesiod. It was also given to her in her worship at the Achaean Aegai. In Eumenides , the priestess announced her first prayers to "Gaia the first prophetess". At Aegai there was a very old image of the earth-goddess, and
2139-527: The brothers of Chione and Cleopatra , wife of Phineus ; king of Thrace . Due to being sons of the north wind they were supernaturally gifted in different ways (depending on changes in the story from being passed down through generations and cultures) either being as fast as the wind or able to fly, having wings either on their feet or backs, depending on the myth. According to Ovid's Metamorphoses , their divine status showed in manhood when they sprouted wings on their backs. They were Argonauts and played
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2208-514: The cult-title Themis . In the Ashmolean Museum a vase shows Pandora (all-giving) rising from the earth and according to some scholars she may be identified with Gaia . "Anesidora" (sending up gifts) on a vase in the British Museum is an epithet of Gaia. Traditionally "gaia" means "earth" and chthon , "under or "beneath the earth" however chthon has occasionally the same meaning with
2277-442: The earth goddess was worshipped together with the sky-god (Zeus). At Thebes there was cult of "Gaia Makaira Telesforos". Telesforos means "bringing fruits to perfection". The earth goddess had powers over the ghosts and the dreams which come from the underworld, therefore she acquired oracular powers. These conceptions are evident in her cults at Delphi , Athens and Aigai of Achaea. An inscription "ieron eurysternou" (sunctuary of
2346-404: The earth, Hittite : tekan , Tocharian : tkam , Phrygian zemelo , Proto-Slavonic : *zem-yã , Avestan : za (locative: zemi ), Vedic : ksam , Latin : hum-us , Albanian : dhé . In Mycenean Greek Ma-ka (probably transliterated as Ma-ga , "Mother Gaia") also contains the root ga- . The Greeks invoked Gaia in their oaths, and she should be aware if one broke his oath. In
2415-508: The earth, and everything born from aether returns to the sky. Nothing is destroyed, but it is transformed to another form.". An inscription on a gravestone in Potidaia mentions: " Aether receives the souls and "chthon" receives the bodies". According to Plutarch: " The name of Ge is beloved to every Greek and she is traditionally honoured like any other god": Hesiod 's Theogony tells how, after Chaos , "wide-bosomed" Gaia (Earth) arose to be
2484-522: The earth. Pherecydes uses the name Chthonie for the primeval goddess who later became Ge and Musaeus the same name for the oracular goddess of Delphi. Homer uses the for chthon the epithets "euryodeia" (broad-seated) and "polyvoteira" (all-nourishing) which can also be used for the earth. In some plays of Aeschylus "chthon" is the earth-goddess Gaia. The tragic poets usually describe Gaia as mother of all, all-nourishing and all-productive who must be honoured. In Aeschylus' Prometheus Unbound , Gaia
2553-503: The everlasting seat of the immortals who possess Olympus above. And after Gaia came "dim Tartarus in the depth of the wide-pathed Earth", and next Eros the god of love. Hesiod goes on to say that Gaia brought forth her equal Uranus (Heaven, Sky) to "cover her on every side". Gaia also bore the Ourea (Mountains), and Pontus (Sea), "without sweet union of love" (i.e., with no father). Afterward, with Uranus, her son, she gave birth to
2622-483: The floor opens to the width of a cubit, and they say that along this bed flowed off the water after the deluge that occurred in the time of Deukalion, and into it they cast every year wheat mixed with honey ... The ancient sanctuary of Zeus Olympios the Athenians say was built by Deukalion (Deucalion), and they cite as evidence that Deukalion lived at Athens a grave which is not far from the present temple. In Athens, there
2691-418: The fully limp flexible wing. Domina Jalbert invented flexible un-sparred ram-air airfoiled thick wings. Natural world: Aviation: Sailing: Gaia (mythology) In Greek mythology , Gaia ( / ˈ ɡ eɪ ə , ˈ ɡ aɪ ə / ; Ancient Greek : Γαῖα , romanized : Gaîa , a poetic form of Γῆ ( Gê ), meaning 'land' or 'earth'), also spelled Gaea ( / ˈ dʒ iː ə / ),
2760-566: The giant one-eyed Cyclopes : Brontes ("Thunder"), Steropes ("Lightning"), and Arges ("Bright"); then the Hecatonchires : Cottus, Briareos, and Gyges, each with a hundred arms and fifty heads. As each of the Cyclopes and Hecatonchires were born, Uranus hid them in a secret place within Gaia, causing her great pain. So Gaia devised a plan. She created a grey flint (or adamantine ) sickle. And Cronus used
2829-453: The goddess. At Olympia her altar was called "Gaios". The altars were given the name of a deity in primitive stages of religion. At Olympia like in Dodona it seems that she was honoured together with the sky-god Zeus . At Aigai she had an oracular power. According to Pliny the priestess drank a small quantity of the blood of a bull before entering the secret cave. At Patras in the oracle of "Ge",
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2898-491: The mortal Heracles , who assisted the Olympians in defeating the Gigantes. According to Hesiod , in his lost poem Astronomia , Orion , while hunting with Artemis and her mother Leto , claimed that he would kill every animal on earth. Gaia, angered by his boasting, sent a giant scorpion to kill him, and after his death, he and the scorpion were placed among the stars by Zeus. According to Ovid , Gaia for some reason sent
2967-399: The mythographer Apollodorus , however, Gaia and Tartarus were the parents of Echidna . The god Hephaestus once attempted to rape Athena , but she pushed him away, causing him to ejaculate on her thigh. Athena wiped off the semen and threw it on the ground, which impregnated Gaia. Gaia then gave birth to Erichthonius of Athens , whom Athena adopted as her own child. Nonnus describes
3036-547: The name of which is Eumolpia, and it is assigned to Musaeus , son of Antiophemus. In it the poet states that the oracle belonged to Poseidon and Earth in common; that Earth gave her oracles herself, but Poseidon used Pyrcon as his mouthpiece in giving responses. The verses are these: "Forthwith the voice of the Earth-goddess uttered a wise word, And with her Pyrcon, servant of the renowned Earth-shaker." They say that afterwards Earth gave her share to Themis, who gave it to Apollo as
3105-429: The novels, Calais (referred to as "Cal") struggles with words that have more than two syllables, including his own name. He has an obsession with ice hockey and pizza . Zetes is by far the more intelligent of the two, though he has his own quirks as well. He is metrosexual and tries to woo the character Piper McLean each time he encounters her. Both Boreads are teenaged, with purple wings and silvery hair; possess
3174-460: The other of Aphrodite ... Next to the grove is a sanctuary of Demeter; she and her daughter [Persephone] are standing, but the image of Ge (Earth) is seated." The Temple of Zeus Olympios in Athens reportedly had an enclosure of Ge Olympia: [Within the sanctuary of Zeus Olympios in the lower town of Athens:] Within the precincts are antiquities: a bronze Zeus, a temple of Kronos (Cronus) and Rhea and an enclosure of Ge (Earth) surnamed Olympia. Here
3243-420: The poems of Hesiod she is personified. Gaia has a significant role in the evolution of the world. She is the nurse of Zeus, and she has the epithet "Kourotrophos". Kourotrophos was the name of an old goddess who was subordinate to Ge. Dieterich believed that Kourotrophos and Potnia theron construct precisely the mother goddess. Ge is also personified in the myths of Erichthonius and Pluto . Erichthonius
3312-411: The sacred marriage between heaven and earth. Ouranos and Gaia are cosmic powers and natural processes. In Chrysippus of Euripides Gaia is the mother of all in a philosophical poetic thought. "Gaia receives the drops of rain bearing the mortals and bearing food and beasts, therefore she is rightly called "mother of all". Aether of Zeus bears men and gods. Everything which is born by the earth returns to
3381-449: The same answers if done correctly. Given a particular wing and its velocity through the air, debates over which mathematical approach is the most convenient to use can be mistaken by those not familiar with the study of aerodynamics as differences of opinion about the basic principles of flight. Wings with an asymmetrical cross-section are the norm in subsonic flight . Wings with a symmetrical cross-section can also generate lift by using
3450-524: The same meaning with gaia . Some of her epithets are similar in some Indo-European languages. The universitality of the goddess is expressed by the prefix pan ,( πάν ). Some of the epithets of Gaia and Demeter are similar showing the identity of their nature. Gaia is believed by some sources to be the original deity behind the Oracle at Delphi . It was thus said: "That word spoken from tree-clad mother Gaia's (Earth's) navel-stone [Omphalos]." Depending on
3519-532: The sanctuaries of other gods. Close to the sanctuary of Eileithyia in Tegea was an altar of Ge; Phlya and Myrrhinos had an altar to Ge under the name Thea Megale (Great goddess); as well as Olympia which additionally, similar to Delphi, also said to have had an oracle to Gaia: On what is called the Gaion (Gaeum, Sanctuary of Ge) [at Olympia] is an altar of Ge (Earth); it too is of ashes. In more ancient days they say that there
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#17328487237853588-497: The scorpion to kill Leto instead, and Orion was killed trying to protect her. When Boreas , the god of the north wind, killed Pitys , an Oread nymph , for rejecting his advances and preferring Pan over him, Gaia pitied the dead girl and transformed her into a pine tree. According to little-known myth, Elaea was an accomplished athlete from Attica who was killed by her fellow athletes, because they had grown envious of her and her skills; but Gaia turned her into an olive tree as
3657-417: The service was in the hands of a virgin woman. The serpent represented the earth deity and was related to the chthonic oracular cult. This is evident at Delphi. Traditionally the oracle belonged originally to Poseidon and Ge and the serpent Python represents the earth spirit. Ge was probably present at the oracle of Trophonius at Livadeia . The prophecies were usually given by the priestesses and not by
3726-528: The sickle to castrate his father Uranus as he approached his mother, Gaia, to have sex with her. From Uranus' spilled blood, Gaia produced the Erinyes , the Giants , and the Meliae (ash-tree nymphs). From the testicles of Uranus in the sea came forth Aphrodite . By her son, Pontus, Gaia bore the sea-deities Nereus , Thaumas , Phorcys , Ceto , and Eurybia . Because Cronus had learned from Gaia and Uranus that he
3795-640: The sisters abandoned themselves into poverty and fatal famine and were eventually snatched away by Zetes and Calais, disappearing from those places ever since. Calais traditionally founded Cales in Campania . The Boreads appear in The Heroes of Olympus series by Rick Riordan , where they reside in Quebec City with their sister Khione and their father Boreas . After their death, their father Boreas transformed them into immortal demigods to act as his lieutenants. In
3864-448: The source, Gaia passed her powers on to Poseidon , Apollo , or Themis . Pausanias wrote: Many and different are the stories told about Delphi, and even more so about the oracle of Apollo. For they say that in the earliest times the oracular seat belonged to Earth, who appointed as prophetess at it Daphnis, one of the nymphs of the mountain. There is extant among the Greeks an hexameter poem,
3933-552: The spouse of Zeus. Homer uses the form "eureia chthon " (broad earth). Hesiod speaks for the broad-breasted earth, ("eurysternos") the sure seat of all immortals. The same epithet appears in her cults at Delphi and Aegae in Achaea. In the Homeric hymn her conception is more clear and detailed. She is the Mother of the Gods, the goddess that brings forth life and blesses men with children. She
4002-506: The title was later applied in Greek texts to Artemis . The mother goddess Cybele from Anatolia (modern Turkey ) was partly identified by the Greeks with Gaia, but more so with Rhea. Beliefs and worship amongst modern pagans (also known as neopagans ) regarding Gaia vary, ranging from the belief that Gaia is the Earth to the belief that she is the spiritual embodiment of the earth or the goddess of
4071-401: The top of the wing generates a smaller downward force on the top of the wing than the upward force generated by the higher air pressure on the bottom of the wing. This gives an upward force on the wing. This force is called the lift generated by the wing. The different velocities of the air passing by the wing, the air pressure differences, the change in direction of the airflow, and the lift on
4140-527: The very pronounced increase in drag associated with airflow near the speed of sound. These airfoils, called supercritical airfoils , are flat on top and curved on the bottom. Aircraft wings may feature some of the following: Aircraft wings may have various devices, such as flaps or slats, that the pilot uses to modify the shape and surface area of the wing to change its operating characteristics in flight. Besides fixed-wing aircraft , applications for wing shapes include: In 1948, Francis Rogallo invented
4209-405: The wing are different ways of describing how lift is produced so it is possible to calculate lift from any one of the other three. For example, the lift can be calculated from the pressure differences, or from different velocities of the air above and below the wing, or from the total momentum change of the deflected air. Fluid dynamics offers other approaches to solving these problems—and all produce
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#17328487237854278-454: The wing. Lower-than-ambient air pressure is generated on the top surface of the wing, with a higher-than ambient-pressure on the bottom of the wing. (See: airfoil ) These air pressure differences can be either measured using a pressure-measuring device, or can be calculated from the airspeed] using physical principles —including Bernoulli's principle , which relates changes in air speed to changes in air pressure. The lower air pressure on
4347-477: The wings of aircraft is one of the principal applications of the science of aerodynamics , which is a branch of fluid mechanics . The properties of the airflow around any moving object can be found by solving the Navier-Stokes equations of fluid dynamics . Except for simple geometries, these equations are difficult to solve. Simpler explanations can be given For a wing to produce "lift", it must be oriented at
4416-580: Was a statue of Gaia on the Acropolis depicting her beseeching Zeus for rain as well as an image of her close to the court of the Areopagos in Athens, alongside the statues of Plouton and Hermes, "by which sacrifice those who have received an acquittal on the Areopagos". Some modern sources, such as Mellaart , Gimbutas , and Walker , claim that Gaia as Mother Earth is a later form of a pre-Indo-European Great Mother , venerated in Neolithic times. Her existence
4485-680: Was a temple of Ge Eurusternos on the Crathis near Aegae in Achaia with "a very ancient statue": It is a journey of about thirty stades [from the stream of Krathis (Crathis) near the ruins of Aigai (Aegae) in Akhaia] to what is called the Gaion (Gaeum), a sanctuary of Ge (Earth) surnamed Eurysternos (Broad-bossomed), whose wooden image is one of the very oldest. The woman who from time to time is priestess henceforth remains chaste and before her election must not have had intercourse with more than one man. The test applied
4554-669: Was an oracle also of Ge (Earth) in this place. On what is called the Stomion (Mouth) the altar to Themis has been built. Her statues were naturally to be found in the temples of Demeter, such as the Temple of Demeter in Achaia: "They [the Patraians of Akhaia (Achaea)] have also a grove by the sea, affording in summer weather very agreeable walks and a pleasant means generally of passing the time. In this grove are also two temples of divinities, one of Apollon,
4623-431: Was destined to be overthrown by one of his children, he swallowed each of the children born to him by his Titan older sister, Rhea. But when Rhea was pregnant with her youngest child, Zeus , she sought help from Gaia and Uranus. When Zeus was born, Rhea gave Cronus a stone wrapped in swaddling-clothes in his place, which Cronus swallowed, and Gaia took the child into her care. With the help of Gaia's advice, Zeus defeated
4692-420: Was fated that they would perish if they failed to catch those they pursued. In some versions, the harpies drop into the sea from exhaustion and so their pursuers fall as well. According to a rare variant of the myth by Tzetzes , the old man Phineus who was blind because of old age had two daughters named Eraseia and Harpyreia . These two lived in a very libertine and lazy life which was all wasted. Ultimately,
4761-543: Was performed to Ge, and the citizents brought offerings to the graves of the dead. An ancient Gaia cult existed at the "Marathonian Tetrapolis" near Athens . In the month Poseideon a pregnant cow was sacrificed to "Ge in the acres" and in Gamelion a sheep to" Ge-near the oracle". Both sacrifices were followed by rituals and the second was related to Daeira a divinity connected with the Eleusinian mysteries. At Eleusis Ge received
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