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Fluvius Eridanus
Eridanus () is a constellation in the southern celestial hemisphere. It is represented as a river. One of the 48 constellations listed by the 2nd century astronomer Ptolemy, it remains one of the 88 modern constellations. It is the sixth largest of the modern constellations, and the one that extends farthest in the sky from north to south. The same name was later taken as a Latin name for the real Po River and also for the name of a minor river in Athens. Features Stars At its southern end is the magnitude 0.5 star Achernar, designated Alpha Eridani. It is a blue-white hued main sequence star 144 light-years from Earth, whose traditional name means "the river's end". Achernar is a very peculiar star because it is one of the flattest stars known. Observations indicate that its radius is about 50% larger at the equator than at the poles. This distortion occurs because the star is spinning extremely rapidly. There are several other noteworthy stars in Eridanus, including so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constellation Eridanus
Eridanus () is a constellation in the southern celestial hemisphere. It is represented as a river. One of the 48 constellations listed by the 2nd century astronomer Ptolemy, it remains one of the 88 modern constellations. It is the sixth largest of the modern constellations, and the one that extends farthest in the sky from north to south. The same name was later taken as a Latin name for the real Po River and also for the name of a minor river in Athens. Features Stars At its southern end is the magnitude 0.5 star Achernar, designated Alpha Eridani. It is a blue-white hued main sequence star 144 light-years from Earth, whose traditional name means "the river's end". Achernar is a very peculiar star because it is one of the flattest stars known. Observations indicate that its radius is about 50% larger at the equator than at the poles. This distortion occurs because the star is spinning extremely rapidly. There are several other noteworthy stars in Eridanus, including so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eridanos (river Of Hades)
The river Eridanos or Eridanus (; grc, Ἠριδανός) is a river in northern Europe mentioned in Greek mythology and historiography. Mythical stream Hesiod, in the ''Theogony,'' calls it "deep-eddying Eridanos" in his list of rivers, the offspring of the Titans Tethys and her brother-husband Oceanus. He was called the king of the rivers. Herodotus suspects the word ''Eridanos'' to be essentially Greek in character, and notably forged by some unknown poet, and expresses his disbelief in the whole concept—passed on to him by others, themselves not eye witnesses—of such a river flowing into a northern sea, surrounding Europe, where the mythical Amber and Tin Isles were supposed; he upholds the belief in the abundance of natural goods at the world's ends though, to be found in the north of Europe as well as in India (east: big animals, gold, cotton) and Arabia (south: incense, myrrh, etc.). The Eridanos was later associated with the river Po, because the Po was located ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Celestial Hemisphere
The southern celestial hemisphere, also called the Southern Sky, is the southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly fixed stars form constellations, appears to rotate westward around a polar axis due to Earth's rotation. At any given time, the entire Southern Sky is visible from the geographic South Pole, while less of this hemisphere is visible the further north the observer is located. The northern counterpart is the northern celestial hemisphere. Astronomy In the context of astronomical discussions or writing about celestial mapping, it may also simply then be referred to as the Southern Hemisphere. For the purpose of celestial mapping, the sky is considered by astronomers as the inside of a sphere divided in two halves by the celestial equator. The Southern Sky or Southern Hemisphere is, therefore, that half of the celestial sphere that is south of the celestial equator. Even if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Eridani
Beta Eridani (β Eridani, abbreviated Beta Eri, β Eri), formally named Cursa , is the second-brightest star in the constellation of Eridanus, located in the northeast end of this constellation near the shared border with Orion. The apparent visual magnitude of this star is 2.796, so it can be viewed with the naked eye in dark skies. Parallax measurements yield an estimated distance of about from the Earth. Nomenclature ''Beta Eridani'' is the star's Bayer designation. It has the traditional name ''Cursa'' derived from ', "the Chair (or "Footstool") of the Central One". This is the name of the star association consisting of this star along with Lambda Eridani, Psi Eridani and Tau Orionis. According to a NASA catalogue of stars, ' was the title of three stars: β Eri is ''Cursa'', Psi Eridani ', and Lambda Eridani ' (excluding Tau Orionis). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or dwarf stars. These are the most numerous true stars in the universe and include the Sun. After condensation and ignition of a star, it generates thermal energy in its dense core region through nuclear fusion of hydrogen into helium. During this stage of the star's lifetime, it is located on the main sequence at a position determined primarily by its mass but also based on its chemical composition and age. The cores of main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sky, night, but their immense distances from Earth make them appear as fixed stars, fixed points of light. The most prominent stars have been categorised into constellations and asterism (astronomy), asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated to stars. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. A star's life star formation, begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Its stellar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0, 6. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Athens
Athens ( ; el, Αθήνα, Athína ; grc, Ἀθῆναι, Athênai (pl.) ) is both the capital and largest city of Greece. With a population close to four million, it is also the seventh largest city in the European Union. Athens dominates and is the capital of the Attica region and is one of the world's oldest cities, with its recorded history spanning over 3,400 years and its earliest human presence beginning somewhere between the 11th and 7th millennia BC. Classical Athens was a powerful city-state. It was a centre for the arts, learning and philosophy, and the home of Plato's Academy and Aristotle's Lyceum. It is widely referred to as the cradle of Western civilization and the birthplace of democracy, largely because of its cultural and political influence on the European continent—particularly Ancient Rome. In modern times, Athens is a large cosmopolitan metropolis and central to economic, financial, industrial, maritime, political and cultural life in Gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eridanos (Athens)
Eridanos or Eridanus (; grc, Ἠριδανός) was a river in Athens mentioned in Greek mythology and historiography. Mythical stream Eridanus was the 'deep-swirling' river-god son of the Titans Oceanus and his sister-wife Tethys. He was the father of Zeuxippe, mother of the Argonauts Butes and Eribotes by Teleon. Eridanus may be the same or different with his another river-god namesake. Real river Eridanus was the small stream that flowed from a source in the foothills of the Lykabettos, through the Agora of ancient Athens in Greece to the archaeological site of the Kerameikos, where its bed is still visible. In this area lives a population of Greek tortoise. Its course has been for the most part covered since ancient times, and was only visible outside the ancient walls in the district of Kerameikos. The river was rediscovered during the excavations for the Athens Metro subway in the late 1990s, and its waters caused considerable technical problems at times. Becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Po River
The Po ( , ; la, Padus or ; Ligurian language (ancient), Ancient Ligurian: or ) is the longest river in Italy. It flows eastward across northern Italy starting from the Cottian Alps. The river's length is either or , if the Maira (river), Maira, a right bank tributary, is included. The headwaters of the Po are a Spring (hydrology), spring seeping from a stony hillside at Pian del Re, a flat place at the head of the Val Po under the northwest face of Monviso. The Po then extends along the 45th parallel north before ending at a delta projecting into the Adriatic Sea near Venice. It is characterized by its large Discharge (hydrology), discharge (several List of rivers by length, rivers over 1,000 km have a discharge inferior or equal to the Po). It is, with the Rhône and Nile, one of the three Mediterranean rivers with the largest water discharge. As a result of its characteristics, the river is subject to heavy flooding. Consequently, over half its length is controlled with Leve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the Roman Republic it became the dominant language in the Italian region and subsequently throughout the Roman Empire. Even after the fall of Western Rome, Latin remained the common language of international communication, science, scholarship and academia in Europe until well into the 18th century, when other regional vernaculars (including its own descendants, the Romance languages) supplanted it in common academic and political usage, and it eventually became a dead language in the modern linguistic definition. Latin is a highly inflected language, with three distinct genders (masculine, feminine, and neuter), six or seven noun cases (nominative, accusative, genitive, dative, ablative, and vocative), five declensions, four verb conjuga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Constellations By Area
The International Astronomical Union (IAU) designates 88 constellations of stars. In the table below, they are ranked by the solid angle that they subtend in the sky, measured in square degrees and millisteradians. These solid angles depend on arbitrary boundaries between the constellations: the list below is based on constellation boundaries drawn up by Eugène Delporte in 1930 on behalf of the IAU and published in ''Délimitation scientifique des constellations'' (Cambridge University Press). Before Delporte's work, there was no standard list of the boundaries of each constellation. Delporte drew the boundaries along vertical and horizontal lines of right ascension and declination; however, he did so for the epoch B1875.0, which means that due to precession of the equinoxes, the borders on a modern star map (e.g., for epoch J2000) are already somewhat skewed and no longer perfectly vertical or horizontal. This skew will increase over the centuries to come. However, this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
