Aries is one of the constellations of the zodiac. It is located in the Northern celestial hemisphere between Pisces to the west and Taurus to the east. The name Aries is Latin for ram. Its old astronomical symbol is (♈︎). It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is a mid-sized constellation ranking 39th in overall size, with an area of 441 square degrees (1.1% of the celestial sphere).
Aries has represented a ram since late Babylonian times. Before that, the stars of Aries formed a farmhand. Different cultures have incorporated the stars of Aries into different constellations including twin inspectors in China and a porpoise in the Marshall Islands. Aries is a relatively dim constellation, possessing only four bright stars: Hamal (Alpha Arietis, second magnitude), Sheratan (Beta Arietis, third magnitude), Mesarthim (Gamma Arietis, fourth magnitude), and 41 Arietis (also fourth magnitude). The few deep-sky objects within the constellation are quite faint and include several pairs of interacting galaxies. Several meteor showers appear to radiate from Aries, including the Daytime Arietids and the Epsilon Arietids.
A number of features exist that are of interest to astronomers. Taurus hosts two of the nearest open clusters to Earth, the Pleiades and the Hyades, both of which are visible to the naked eye. At first magnitude, the red giantAldebaran is the brightest star in the constellation. In the northeast part of Taurus is Messier 1, more commonly known as the Crab Nebula, a supernova remnant containing a pulsar. One of the closest regions of active star formation, the Taurus-Auriga complex, crosses into the northern part of the constellation. The variable starT Tauri is the prototype of a class of pre-main-sequence stars.
Cancer is one of the twelve constellations of the zodiac and is located in the Northern celestial hemisphere. Its old astronomical symbol is (♋︎). Its name is Latin for crab and it is commonly represented as one. Cancer is a medium-size constellation with an area of 506 square degrees and its stars are rather faint, its brightest star Beta Cancri having an apparent magnitude of 3.5. It contains ten stars with known planets, including 55 Cancri, which has five: one super-earth and four gas giants, one of which is in the habitable zone and as such has expected temperatures similar to Earth. At the (angular) heart of this sector of our celestial sphere is Praesepe (Messier 44), one of the closest open clusters to Earth and a popular target for amateur astronomers.
Leo/ˈliːoʊ/ is one of the constellations of the zodiac, between Cancer the crab to the west and Virgo the maiden to the east. It is located in the Northern celestial hemisphere. Its name is Latin for lion, and to the ancient Greeks represented the Nemean Lion killed by the mythical Greek hero Heracles as one of his twelve labors. Its old astronomical symbol is (♌︎). One of the 48 constellations described by the 2nd-century astronomer Ptolemy, Leo remains one of the 88 modern constellations today, and one of the most easily recognizable due to its many bright stars and a distinctive shape that is reminiscent of the crouching lion it depicts.
Leo is associated with fire, accompanied by Aries and Sagittarius, and its modality is fixed. The constellation Leo is associated with the mythological Nemean lion.[3] The lion is a very important and prominent symbol in Greek mythology.[2][4]
Leo on the reverse of the gold coin of Jahangir of India
Egyptians worshipped the constellation, which they referred to as "Knem", because it was present during the flooding of the Nile River. This event signified plentiful harvests for the upcoming year, and the people interpreted it as a gift from the earth. Ruler of Egypt, Tutankhamun's gold throne features lion heads where the seat and front legs meet, as well as clawed feet at the end of each leg, symbolizing power and royalty.[5]
Virgo is one of the constellations of the zodiac. Its name is Latin for maiden, and its old astronomical symbol is . Between Leo to the west and Libra to the east, it is the second-largest constellation in the sky (after Hydra) and the largest constellation in the zodiac. The ecliptic intersects the celestial equator within this constellation and Pisces. Underlying these technical two definitions, the sun passes directly overhead of the equator, within this constellation, at the September equinox. Virgo can be easily found through its brightest star, Spica.
Scorpius is a zodiacconstellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation whose recognition predates Greek culture;[1] it is one of the 48 constellations identified by the Greek astronomer Ptolemy in the second century.
In Greek mythology, several myths associated with Scorpius attribute it to Orion. According to one version, Orion boasted to the goddess Artemis and her mother, Leto, that he would kill every animal on Earth. Artemis and Leto sent a scorpion to kill Orion.[12] Their battle caught the attention of Zeus, who raised both combatants to the sky to serve as a reminder for mortals to curb their excessive pride. In another version of the myth, Artemis' twin brother, Apollo, was the one who sent the scorpion to kill Orion after the hunter earned the goddess' favor by admitting she was better than him. After Zeus raised Orion and the scorpion to the sky, the former hunts every winter but flees every summer when the scorpion comes. In both versions, Artemis asked Zeus to raise Orion.
In a Greek myth without Orion, the celestial scorpion encountered Phaethon while he was driving his father Helios' Sun Chariot.[13]
Scorpio (♏︎) (Ancient Greek: Σκορπιός, romanized: Skorpiós, Latin for "scorpion") is the eighth astrological sign in the zodiac, originating from the constellation of Scorpius. It spans 210–240° ecliptic longitude. Under the tropical zodiac (most commonly used in Western astrology), the Sun transits this sign on average from October 23 to November 21.[2] Depending on which zodiac system one uses, someone born under the influence of Scorpio may be called a Scorpio or a Scorpionic.[2]
Capricornus/ˌkæprɪˈkɔːrnəs/ is one of the constellations of the zodiac. Its name is Latin for "horned goat" or "goat horn" or "having horns like a goat's", and it is commonly represented in the form of a sea goat: a mythical creature that is half goat, half fish.
Capricornus is one of the 88 modern constellations, and was also one of the 48 constellations listed by the 2nd century astronomer Claudius Ptolemy. Its old astronomical symbol is (♑︎). Under its modern boundaries it is bordered by Aquila, Sagittarius, Microscopium, Piscis Austrinus, and Aquarius. The constellation is located in an area of sky called the Sea or the Water, consisting of many water-related constellations such as Aquarius, Pisces and Eridanus. It is the smallest constellation in the zodiac.
The hippocampus or hippocamp, also hippokampos (plural: hippocampi or hippocamps; Ancient Greek: ἱππόκαμπος, from ἵππος, 'horse', and κάμπος, 'sea monster'[1]), often called a sea-horse[2] in English,[citation needed] is a mythological creature shared by Phoenician,[3]Etruscan, Pictish, Roman and Greek mythology, though its name has a Greek origin. The hippocampus has typically been depicted as having the upper body of a horse with the lower body of a fish.
n the Iliad, Homer describes Poseidon, god of horses, earthquakes, and the sea, driving a chariot drawn by brazen-hoofed horses over the sea's surface,[7] and Apollonius of Rhodes, describes the horse of Poseidon emerging from the sea and galloping across the Libyan sands.[8] This compares to the specifically "two-hoofed" hippocampi of Gaius Valerius Flaccus in his Argonautica: "Orion when grasping his father’s reins heaves the sea with the snorting of his two-hooved horses."[9] In Hellenistic and Roman imagery, however, Poseidon (or Roman Neptune) often drives a sea-chariot drawn by hippocampi. Thus, hippocampi sport with this god in both ancient depictions and much more modern ones, such as in the waters of the 18th-century Trevi Fountain in Rome surveyed by Neptune from his niche above.
The appearance of hippocampi in both freshwater and saltwater is counter-intuitive to a modern audience, though not to an ancient one. The Greek picture of the natural hydrological cycle did not take into account the condensation of atmospheric water as rain to replenish the water table, but imagined the waters of the sea oozing back landwards through vast caverns and aquifers, rising replenished and freshened in springs.[10]
Thus, it was natural for a temple at Helike in the coastal plain of Achaea to be dedicated to Poseidon Helikonios, (the Poseidon of Helicon), the sacred spring of Boeotian Helikon.[11] When an earthquake suddenly submerged the city, the temple's bronze Poseidon accompanied by hippocampi continued to snag fishermens' nets.[12] Likewise, the hippocampus was considered an appropriate decoration for mosaics in Roman thermae or public baths, as at Aquae Sulis modern day Bath in Britannia.
Poseidon's horses, which were included in the elaborate sculptural program of gilt-bronze and ivory, added by a Roman client to the temple of Poseidon at Corinth, are likely to have been hippocampi; the Romanised Greek Pausanias described the rich ensemble in the later 2nd century AD (Geography of Greece ii.1.7-.8):
On the temple, which is not very large, stand bronze Tritons. In the fore-temple are images, two of Poseidon, a third of Amphitrite, and a Sea, which also is of bronze. The offerings inside were dedicated in our time by Herodes Atticus, four horses, gilded except for the hoofs, which are of ivory, and two gold Tritons beside the horses, with the parts below the waist of ivory. On the car stand Amphitrite and Poseidon, and there is the boy Palaemon upright upon a dolphin. These too are made of ivory and gold. On the middle of the base on which the car has been wrought a Sea holding up the young Aphrodite, and on either side are the nymphs called Nereids.
Its brightest star, Altair, is one vertex of the Summer Triangleasterism. The constellation is best seen in the northern summer, as it is located along the Milky Way. Because of this location, many clusters and nebulae are found within its borders, but they are dim and galaxies are few.
In classical Greek mythology, Aquila was identified as Αετός Δίας (Aetos Dios), the eagle that carried the thunderbolts of Zeus and was sent by him to carry the shepherd boy Ganymede, whom he desired, to Mount Olympus; the constellation of Aquarius is sometimes identified with Ganymede.[1]
In the Chinese love story of Qi Xi, Niu Lang (Altair) and his two children (β and γ Aquilae) are separated forever from their wife and mother Zhi Nu (Vega), who is on the far side of the river, the Milky Way.[49]
In Hinduism, the constellation Aquila is identified with the half-eagle half-human deity Garuda.[50][51]
In ancient Egypt, Aquila possibly was seen as the falcon of Horus.[52] According to Berio, the identification of Aquila as an Egyptian constellation, and not merely Graeco-Babylonian, is corroborated by the Daressy Zodiac.[53] It depicts an outer ring showing the Sphaera Graeca, the familiar Hellenistic zodiac, while the middle ring depicts the Sphaera Barbarica or foreigner's zodiac with the zodiacal signs of the Egyptian dodekaoros which were also recorded by Teucros of Babylon.[54] Under the sign of Sagittarius is the falcon of Horus, presumably because Aquila rises with Sagittarius.
Aquila, which lies in the Milky Way, contains many rich starfields and has been the location of many novae.[1]
α Aql (Altair) is the brightest star in this constellation and one of the closest naked-eye stars to Earth at a distance of 17 light-years. Its name comes from the Arabic phrase al-nasr al-tair, meaning "the flying eagle". Altair has a magnitude of 0.76.[1] It is one of the three stars of the Summer Triangle, along with Vega and Deneb.[6][7][8] It is an A-type main-sequence star with 1.8 times the mass of the Sun and 11 times its luminosity.[9][10] The star rotates quickly, and this gives the star an oblate shape where it is flattened towards the poles.[9][10][11]
β Aql (Alshain) is a yellow-hued star of magnitude 3.7, 45 light-years from Earth. Its name comes from the Arabic phrase shahin-i tarazu, meaning "the balance"; this name referred to Altair, Alshain, and Tarazed.[1] The primary is a G-type subgiant star with a spectral type of G9.5 IV and the secondary is a red dwarf.[12][13] The subgiant primary has three times the radius of the Sun and six times the luminosity.[14]
γ Aql (Tarazed) is an orange-hued giant star of around magnitude 2.7,[15] 460 light-years from Earth. Its name, like that of Alshain, comes from the Arabic for "the balance".[1] It is the second-brightest star in the constellation and is an unconfirmed variable star.[16]
15 Aql is an optical double star. The primary is an orange-hued giant of magnitude 5.41 and a spectral type of K1 III,[26][27] 325 light-years from Earth. The secondary is a purple-hued star of magnitude 7.0, 550 light-years from Earth. The pair is easily resolved in small amateur telescopes.[1]
57 Aql is a binary star. The primary is a blue-hued star of magnitude 5.7 and the secondary is a white star of magnitude 6.5. The system is approximately 350 light-years from Earth; the pair is easily resolved in small amateur telescopes.[1] Both stars in the system rotate rapidly.[28]
R Aql is a red-hued giant star 690 light-years from Earth. It is a Mira variable with a minimum magnitude of 12.0, a maximum magnitude of 6.0, and a period around 9 months. It has a diameter of 400 D☉.[1]
V Aql is a typical Cool Carbon Star. It's one of the most red-colored examples of this sort of stars, observable through common amateur telescopes.
FF Aql is a yellow-white-hued supergiant star, 2500 light-years from Earth. It is a Cepheid variable star with a minimum magnitude of 5.7, a maximum magnitude of 5.2, and a period of 4.5 days.[1] It is a spectroscopic binary with a spectral type of F6Ib.[29] A third star is also a member of the system,[30] and there is also a fourth star which is probably unconnected with the main system.[31][32]
Pisces is a constellation of the zodiac. Its vast bulk – and main asterism viewed in most European cultures per Greco-Roman antiquity as a distant pair of fishes connected by one cord each that join at an apex – are in the Northern celestial hemisphere. Its old astronomical symbol is (♓︎). Its name is Latin for "fishes". It is between Aquarius, of similar size, to the southwest and Aries, which is smaller, to the east. The ecliptic and the celestial equator intersect within this constellation and in Virgo. The Sun passes directly overhead of the equator, on average, at approximately this point in the sky, at the March equinox.
Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification.[2]
Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water.[3]
Many inorganic substances which bear the word hydroxide in their names are not ionic compounds of the hydroxide ion, but covalent compounds which contain hydroxy
In chemistry, hydronium (hydroxonium in traditional British English) is the cation[H3O]+, also written as H3O+, the type of oxonium ion produced by protonation of water. It is often viewed as the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a proton (a positive hydrogen ion, H+) to the surrounding water molecules (H2O). In fact, acids must be surrounded by more than a single water molecule in order to ionize, yielding aqueous H+ and conjugate base.
Three main structures for the aqueous proton have garnered experimental support:
the Eigen cation, which is a tetrahydrate, H3O+(H2O)3
the Zundel cation, which is a symmetric dihydrate, H+(H2O)2
and the Stoyanov cation, an expanded Zundel cation, which is a hexahydrate: H+(H2O)2(H2O)4[1][2]
Spectroscopic evidence from well-defined IR spectra overwhelmingly supports the Stoyanov cation as the predominant form.[3][4][5][6][non-primary source needed] For this reason, it has been suggested that wherever possible, the symbol H+(aq) should be used instead of the hydronium ion.[2]
The self-ionization of water (also autoionization of water, autoprotolysis of water, autodissociation of water, or simply dissociation of water) is an ionization reaction in pure water or in an aqueous solution, in which a water molecule, H2O, deprotonates (loses the nucleus of one of its hydrogen atoms) to become a hydroxide ion, OH−. The hydrogen nucleus, H+, immediately protonates another water molecule to form a hydronium cation, H3O+. It is an example of autoprotolysis, and exemplifies the amphoteric nature of water.
The self-ionization of water was first proposed in 1884 by Svante Arrhenius as part of the theory of ionic dissociation which he proposed to explain the conductivity of electrolytes including water. Arrhenius wrote the self-ionization as . At that time, nothing was yet known of atomic structure or subatomic particles, so he had no reason to consider the formation of an ion from a hydrogen atom on electrolysis as any less likely than, say, the formation of a ion from a sodium atom.
In 1923 Johannes Nicolaus Brønsted and Martin Lowry proposed that the self-ionization of water actually involves two water molecules: . By this time the electron and the nucleus had been discovered and Rutherford had shown that a nucleus is very much smaller than an atom. This would include a bare ion which would correspond to a proton with zero electrons. Brønsted and Lowry proposed that this ion does not exist free in solution, but always attaches itself to a water (or other solvent) molecule to form the hydronium ion (or other protonated solvent).
Later spectroscopic evidence has shown that many protons are actually hydrated by more than one water molecule. The most descriptive notation for the hydrated ion is , where aq (for aqueous) indicates an indefinite or variable number of water molecules. However the notations and are still also used extensively because of their historical importance. This article mostly represents the hydrated proton as , corresponding to hydration by a single water molecule.
Conductivity or specific conductance of an electrolyte solution is a measure of its ability to conduct electricity. The SI unit of conductivity is siemens per meter (S/m).
Conductivity measurements are used routinely in many industrial and environmental applications as a fast, inexpensive and reliable way of measuring the ionic content in a solution.[1] For example, the measurement of product conductivity is a typical way to monitor and continuously trend the performance of water purification systems.
The electrolytic conductivity of ultra-high purity water increases as a function of temperature (T) due to the higher dissociation of H2O in H+ andOH− with T.
High quality deionized water has a conductivity of at 25 °C. This corresponds to a specific resistivity of .[2] The preparation of salt solutions often takes place in unsealed beakers. In this case the conductivity of purified water often is 10 to 20 times higher. A discussion can be found below.
Typical drinking water is in the range of 200–800 μS/cm, while sea water is about 50 mS/cm[3] (or 0.05 S/cm).
Conductivity is traditionally determined by connecting the electrolyte in a Wheatstone bridge. Dilute solutions follow Kohlrausch's law of concentration dependence and additivity of ionic contributions. Lars Onsager gave a theoretical explanation of Kohlrausch's law by extending Debye–Hückel theory.
Theory [ edit ] The underlying premise of spectroscopy is that light is made of different wavelengths and that each wavelength corresponds to a different frequency. The importance of spectroscopy is centered around the fact that every element in the periodic table has a unique light spectrum described by the frequencies of light it emits or absorbs consistently appearing in the same part of the electromagnetic spectrum when that light is diffracted. This opened up an entire field of study with anything that contains atoms. Spectroscopy is the key to understanding the atomic properties of all matter. As such spectroscopy opened up many new sub-fields of science yet undiscovered. The idea that each atomic element has its unique spectral signature enabled spectroscopy to be used in a broad number of fields each with a specific goal achieved by different spectroscopic procedures. The National Institute of Standards and Technology maintains a public Atomic Spec...
"The Golden Number is not the product of mathematical imagination but the natural principle of the laws of equilibrium." From averages established from measurements of the human body, it has been proved that the navel divides the total height of the body in the proportion of Φ to 1. This formula is applied to classical Greek sculpture, and in Egypt as well, except that in Egypt the crown of the head is excluded. Let us recall, in this regard, the significance of the value Φ and the geometric structure that defines Φ. The value , or the Golden Number Φ , corresponds to the proportion C / B = B / A when C = A + B There i...
.svg){kind=small}
(♈︎). It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is a mid-sized constellation ranking 39th in overall size, with an area of 441 square degrees (1.1% of the celestial sphere).
.svg){kind=small}
(♉︎), which resembles a bull's head..svg){kind=small}
(♊︎)..svg)
.svg){kind=small}
(♋︎). Its name is Latin for crab and it is commonly represented as one. Cancer is a medium-size constellation with an area of 506 square degrees and its stars are rather faint, its brightest star Beta Cancri having an apparent magnitude of 3.5. It contains ten stars with known planets, including 55 Cancri, which has five: one super-earth and four gas giants, one of which is in the habitable zone and as such has expected temperatures similar to Earth. At the (angular) heart of this sector of our celestial sphere is Praesepe (Messier 44), one of the closest open clusters to Earth and a popular target for amateur astronomers..svg)
.svg){kind=small}
(♌︎). One of the 48 constellations described by the 2nd-century astronomer Ptolemy, Leo remains one of the 88 modern constellations today, and one of the most easily recognizable due to its many bright stars and a distinctive shape that is reminiscent of the crouching lion it depicts..svg)
. Between Leo to the west and Libra to the east, it is the second-largest constellation in the sky (after Hydra) and the largest constellation in the zodiac. The ecliptic intersects the celestial equator within this constellation and Pisces. Underlying these technical two definitions, the sun passes directly overhead of the equator, within this constellation, at the September equinox. Virgo can be easily found through its brightest star, Spica.
.svg){kind=small}
.svg)
.svg){kind=small}
(♎︎). It is fairly faint, with no first magnitude stars, and lies between Virgo to the west and Scorpius to the east. Beta Librae, also known as Zubeneschamali, is the brightest star in the constellation. Three star systems are known to have planets.
.svg){kind=small}
(♑︎). Under its modern boundaries it is bordered by Aquila, Sagittarius, Microscopium, Piscis Austrinus, and Aquarius. The constellation is located in an area of sky called the Sea or the Water, consisting of many water-related constellations such as Aquarius, Pisces and Eridanus. It is the smallest constellation in the zodiac.
.svg){kind=small}
(♓︎). Its name is Latin for "fishes". It is between Aquarius, of similar size, to the southwest and Aries, which is smaller, to the east. The ecliptic and the celestial equator intersect within this constellation and in Virgo. The Sun passes directly overhead of the equator, on average, at approximately this point in the sky, at the March equinox.
Comments
Post a Comment