The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, the largest among planetary satellites relative to the size of the planet that it orbits; the Moon is after Jupiter's satellite Io the second-densest satellite in the Solar System among those whose densities are known. The Moon is thought to have formed not long after Earth; the most accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars-sized body called Theia. The Moon is in synchronous rotation with Earth, thus always shows the same side to Earth, the near side; the near side is marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters. After the Sun, the Moon is the second-brightest visible celestial object in Earth's sky, its surface is dark, although compared to the night sky it appears bright, with a reflectance just higher than that of worn asphalt.
Its gravitational influence produces the ocean tides, body tides, the slight lengthening of the day. The Moon's average orbital distance is 1.28 light-seconds. This is about thirty times the diameter of Earth; the Moon's apparent size in the sky is the same as that of the Sun, since the star is about 400 times the lunar distance and diameter. Therefore, the Moon covers the Sun nearly during a total solar eclipse; this matching of apparent visual size will not continue in the far future because the Moon's distance from Earth is increasing. The Moon was first reached in September 1959 by an unmanned spacecraft; the United States' NASA Apollo program achieved the only manned lunar missions to date, beginning with the first manned orbital mission by Apollo 8 in 1968, six manned landings between 1969 and 1972, with the first being Apollo 11. These missions returned lunar rocks which have been used to develop a geological understanding of the Moon's origin, internal structure, the Moon's history. Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft.
Both the Moon's natural prominence in the earthly sky and its regular cycle of phases as seen from Earth have provided cultural references and influences for human societies and cultures since time immemorial. Such cultural influences can be found in language, lunar calendar systems and mythology; the usual English proper name for Earth's natural satellite is "the Moon", which in nonscientific texts is not capitalized. The noun moon is derived from Old English mōna, which stems from Proto-Germanic *mēnô, which comes from Proto-Indo-European *mḗh₁n̥s "moon", "month", which comes from the Proto-Indo-European root *meh₁- "to measure", the month being the ancient unit of time measured by the Moon; the name "Luna" is used. In literature science fiction, "Luna" is used to distinguish it from other moons, while in poetry, the name has been used to denote personification of Earth's moon; the modern English adjective pertaining to the Moon is lunar, derived from the Latin word for the Moon, luna. The adjective selenic is so used to refer to the Moon that this meaning is not recorded in most major dictionaries.
It is derived from the Ancient Greek word for the Moon, σελήνη, from, however derived the prefix "seleno-", as in selenography, the study of the physical features of the Moon, as well as the element name selenium. Both the Greek goddess Selene and the Roman goddess Diana were alternatively called Cynthia; the names Luna and Selene are reflected in terminology for lunar orbits in words such as apolune and selenocentric. The name Diana comes from the Proto-Indo-European *diw-yo, "heavenly", which comes from the PIE root *dyeu- "to shine," which in many derivatives means "sky and god" and is the origin of Latin dies, "day"; the Moon formed 4.51 billion years ago, some 60 million years after the origin of the Solar System. Several forming mechanisms have been proposed, including the fission of the Moon from Earth's crust through centrifugal force, the gravitational capture of a pre-formed Moon, the co-formation of Earth and the Moon together in the primordial accretion disk; these hypotheses cannot account for the high angular momentum of the Earth–Moon system.
The prevailing hypothesis is that the Earth–Moon system formed after an impact of a Mars-sized body with the proto-Earth. The impact blasted material into Earth's orbit and the material accreted and formed the Moon; the Moon's far side has a crust, 30 mi thicker than that of the near side. This is thought to be; this hypothesis, although not perfect best explains the evidence. Eighteen months prior to an October 1984 conference on lunar origins, Bill Hartmann, Roger Phillips, Jeff Taylor challenged fellow lunar scientists: "You have eighteen months. Go back to your Apollo data, go back to your computer, do whatever you have to, but make up your mind. Don't come to our conference unless you have something to say about the Moon's birth." At the 1984 conference at Kona, the giant impact hypothesis emerged as the most consensual theory. Before the conference, there were parti
Shani refers to the planet Saturn, is one of the nine heavenly objects known as Navagraha in Hindu astrology. Shani is a male deity in the Puranas, whose iconography consists of a handsome figure carrying a sword or danda, sitting on a crow, he is a god of Justice in Hindu mythology and he gives benefits to all, depending upon their deeds. His consort is goddess Manda. Shani as a planet appears in various Hindu astronomical texts in Sanskrit, such as the 5th century Aryabhatiya by Aryabhatta, the 6th-century Romaka by Latadeva and Panca Siddhantika by Varahamihira, the 7th century Khandakhadyaka by Brahmagupta and the 8th century Sisyadhivrddida by Lalla; these texts present Shani as one of the planets and estimate the characteristics of the respective planetary motion. Other texts such as Surya Siddhanta dated to have been complete sometime between the 5th century and 10th century present their chapters on various planets as divine knowledge linked to deities; the manuscripts of these texts exist in different versions, present Shani's motion in the skies, but vary in their data, suggesting that the text were open and revised over their lives.
The texts disagree in their data, in their measurements of Shani's revolutions, epicycles, nodal longitudes, orbital inclination, other parameters. For example, both Khandakhadyaka and Surya Siddhanta of Varaha state that Shani completes 146,564 revolutions on its own axis every 4,320,000 earth years, an Epicycle of Apsis as 60 degrees, had an apogee of 240 degrees in 499 CE; the 1st millennium CE Hindu scholars had estimated the time it took for sidereal revolutions of each planet including Shani, from their astronomical studies, with different results: Shani is the basis for Shanivara – one of the seven days that make a week in the Hindu calendar. This day corresponds to Saturday – after Saturn – in the Greco-Roman convention for naming the days of the week; the zodiac and naming system of Hindu astrology, including those on Shani as Saturn developed in the centuries after the arrival of Greek astrology with Alexander the Great, their zodiac signs being nearly identical. Shani is a deity in medieval era texts, considered inauspicious and the bringer of bad luck.
He is a deity who gets angry and takes revenge on whoever made him upset. In medieval Hindu literature, inconsistent mythologies sometimes refer to him as the son of Sun and Chayya, or as the son of Balarama and Revati, his alternate names include Ara and Kroda. The fig tree called Pipal in some Indian texts is the abode of Shani. In 2013, a 20-foot-tall statue of Lord Shani was established at Yerdanur in the mandal of Sangareddy, Medak district, nearly 40 kilometers from Hyderabad city, it was carved from a monolith and weighs about nine tonnes. Daya Shankar Pandey played the role of Shani Dev in Mahima Shani Dev Ki which aired on NDTV Imagine from 2010 to 2012. On November 7, 2016 the show Karmafal Daata Shani aired on Colors TV. Kartikey Malviya plays the role of younger Shani and Rohit Khurana of mature Shani; the show ended on March 9, 2018. In 2017 the remake of the Karmafal Daata Shani was made in Kannada titled Shani telecasted on Colors Kannada. Sunil plays the role of young Shani. In 2018 the Karmafal Daata Shani was dubbed in Tamil titled Sangadam theerkum Saneeshwaran was telecasted on Colors Tamil.
Svoboda, Robert. The Greatness of Saturn: A Therapeutic Myth. Lotus Press, 1997. ISBN 0-940985-62-4 Pingree, David. "The Mesopotamian Origin of Early Indian Mathematical Astronomy". Journal for the History of Astronomy. SAGE. 4. Doi:10.1177/002182867300400102. Pingree, David. Jyotihśāstra: Astral and Mathematical Literature. Otto Harrassowitz. ISBN 978-3-447-02165-4. Yukio Ohashi. Johannes Andersen, ed. Highlights of Astronomy, Volume 11B. Springer Science. ISBN 978-0-7923-5556-4. Astronomical Names for the Days of the Week, M Falk The God Shani or the Planet Saturn, Iconongraphy on a column in Madurai Meenakshi Temple, British Library
Mercury is the smallest and innermost planet in the Solar System. Its orbital period around the Sun of 87.97 days is the shortest of all the planets in the Solar System. It is named after the messenger of the gods. Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, never exceeds 28° away from the Sun when viewed from Earth; this proximity to the Sun means the planet can only be seen near the western or eastern horizon during the early evening or early morning. At this time it may appear as a bright star-like object, but is far more difficult to observe than Venus; the planet telescopically displays the complete range of phases, similar to Venus and the Moon, as it moves in its inner orbit relative to Earth, which reoccurs over the so-called synodic period every 116 days. Mercury is tidally locked with the Sun in a 3:2 spin-orbit resonance, rotates in a way, unique in the Solar System; as seen relative to the fixed stars, it rotates on its axis three times for every two revolutions it makes around the Sun.
As seen from the Sun, in a frame of reference that rotates with the orbital motion, it appears to rotate only once every two Mercurian years. An observer on Mercury would therefore see only one day every two Mercurian years. Mercury's axis has the smallest tilt of any of the Solar System's planets, its orbital eccentricity is the largest of all known planets in the Solar System. Mercury's surface appears cratered and is similar in appearance to the Moon's, indicating that it has been geologically inactive for billions of years. Having no atmosphere to retain heat, it has surface temperatures that vary diurnally more than on any other planet in the Solar System, ranging from 100 K at night to 700 K during the day across the equatorial regions; the polar regions are below 180 K. The planet has no known natural satellites. Two spacecraft have visited Mercury: Mariner 10 flew by in 1974 and 1975; the BepiColombo spacecraft is planned to arrive at Mercury in 2025. Mercury appears to have a solid silicate crust and mantle overlying a solid, iron sulfide outer core layer, a deeper liquid core layer, a solid inner core.
Mercury is one of four terrestrial planets in the Solar System, is a rocky body like Earth. It is the smallest planet in the Solar System, with an equatorial radius of 2,439.7 kilometres. Mercury is smaller—albeit more massive—than the largest natural satellites in the Solar System and Titan. Mercury consists of 70% metallic and 30% silicate material. Mercury's density is the second highest in the Solar System at 5.427 g/cm3, only less than Earth's density of 5.515 g/cm3. If the effect of gravitational compression were to be factored out from both planets, the materials of which Mercury is made would be denser than those of Earth, with an uncompressed density of 5.3 g/cm3 versus Earth's 4.4 g/cm3. Mercury's density can be used to infer details of its inner structure. Although Earth's high density results appreciably from gravitational compression at the core, Mercury is much smaller and its inner regions are not as compressed. Therefore, for it to have such a high density, its core must be rich in iron.
Geologists estimate. Research published in 2007 suggests. Surrounding the core is a 500–700 km mantle consisting of silicates. Based on data from the Mariner 10 mission and Earth-based observation, Mercury's crust is estimated to be 35 km thick.. One distinctive feature of Mercury's surface is the presence of numerous narrow ridges, extending up to several hundred kilometers in length, it is thought that these were formed as Mercury's core and mantle cooled and contracted at a time when the crust had solidified. Mercury's core has a higher iron content than that of any other major planet in the Solar System, several theories have been proposed to explain this; the most accepted theory is that Mercury had a metal–silicate ratio similar to common chondrite meteorites, thought to be typical of the Solar System's rocky matter, a mass 2.25 times its current mass. Early in the Solar System's history, Mercury may have been struck by a planetesimal of 1/6 that mass and several thousand kilometers across.
The impact would have stripped away much of the original crust and mantle, leaving the core behind as a major component. A similar process, known as the giant impact hypothesis, has been proposed to explain the formation of the Moon. Alternatively, Mercury may have formed from the solar nebula before the Sun's energy output had stabilized, it would have had twice its present mass, but as the protosun contracted, temperatures near Mercury could have been between 2,500 and 3,500 K and even as high as 10,000 K. Much of Mercury's surface rock could have been vaporized at such temperatures, forming an atmosphere of "rock vapor" that could have been carried away by the solar wind. A third hypothesis proposes that the solar nebula caused drag on the particles from which Mercury was accreting, which meant that lighter particles were lost from the accreting material and not gathered by Mercury; each hypothesis predicts a different surface composition, there are two space missions set to make observations.
In classical antiquity, the seven classical planets are the seven non-fixed astronomical objects in the sky visible to the naked eye: Mars, Venus, Mercury, the Sun, the Moon. The word planet comes from two related Greek words, πλάνης planēs and πλανήτης planētēs, both with the original meaning of "wanderer", expressing the fact that these objects move across the celestial sphere relative to the fixed stars. Greek astronomers such as Geminus and Ptolemy divided the seven planets into the Sun, the Moon, the five planets; the term planet in modern terminology is only applied to natural satellites directly orbiting the Sun, so that of the seven classical planets, five are planets in the modern sense. Babylonians recognized seven planets. A bilingual list in the British Museum records the seven Babylonian planets in this order: The astrological symbols for the classical planets appear in the medieval Byzantine codices in which many ancient horoscopes were preserved. In the original papyri of these Greek horoscopes, there are found a circle with one ray for the Sun and a crescent for the Moon.
The written symbols for Mercury, Venus and Saturn have been traced to forms found in late Greek papyri. The symbols for Jupiter and Saturn are identified as monograms of the initial letters of the corresponding Greek names, the symbol for Mercury is a stylized caduceus. A. S. D. Maunder finds antecedents of the planetary symbols in earlier sources, used to represent the gods associated with the classical planets. Bianchini's planisphere, produced in the 2nd century, shows Greek personifications of planetary gods charged with early versions of the planetary symbols: Mercury has a caduceus. A diagram in Johannes Kamateros' 12th century Compendium of Astrology shows the Sun represented by the circle with a ray, Jupiter by the letter zeta, Mars by a shield crossed by a spear, the remaining classical planets by symbols resembling the modern ones, without the cross-mark seen in modern versions of the symbols; the modern sun symbol, pictured as a circle with a dot, first appeared in the Renaissance.
The Ptolemaic system used in Greek astronomy placed the planets in order, closest to Earth to furthest, as the Moon, Venus, Mars and Saturn. In addition the day was divided into 7 hour intervals, each ruled by one of the planets, although the order was staggered; the first hour of each day was named after the ruling planet, giving rise to the names and order of the Roman seven-day week. Modern Latin-based cultures, in general, directly inherited the days of the week from the Romans and they were named after the classical planets; the modern English days of the week were inherited from gods of the old Germanic Norse culture — Wednesday is Wōden’s-day, Thursday is Thor’s-day, Friday is Frige-day. It can be correlated that the Norse gods were attributed to each Roman planet and its god due to Roman influence rather than coincidentally by the naming of the planets. In alchemy, each classical planet was associated with one of the seven metals known to the classical world; as a result, the alchemical glyphs for associated planet coincide.
Alchemists believed. Alchemy in the Western World and other locations where it was practiced was allied and intertwined with traditional Babylonian-Greek style astrology. Astrology has used the concept of classical elements from antiquity up until the present day today. Most modern astrologers use the four classical elements extensively, indeed they are still viewed as a critical part of interpreting the astrological chart. Traditionally, each of the seven "planets" in the solar system as known to the ancients was associated with, held dominion over, "ruled" a certain metal; the list of rulership is as follows: The Sun rules Gold The Moon, Silver Mercury, Quicksilver/Mercury Venus, Copper Mars, Iron Jupiter, Tin Saturn, Lead Some alchemists adopted the Hermetic Qabalah assignment between the vital organs and the planets as follows: Indian astronomy and astrology recognises seven visible planets and two additional invisible planets. The cycles of the Chinese calendar are linked to the orbit of Jupiter, there being 12 sacred beasts in the Chinese dodecannualar geomantic and astrological cycle, 12 years in the orbit of Jupiter.
Mercury and Venus are visible only in twilight hours because their orbits are interior to that of Earth. Venus is the third-brightest object in the most prominent planet. Mercury is more difficult to see due to its proximity to the Sun. Lengthy twilight and an low angle at maximum elongations make optical filters necessary to see Mercury from extreme polar locations. Mars is at its brightest when it is in opposition, which occurs every twenty-five months. Jupiter and Sat
Astrology is a pseudoscience that claims to divine information about human affairs and terrestrial events by studying the movements and relative positions of celestial objects. Astrology has been dated to at least the 2nd millennium BCE, has its roots in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communications. Many cultures have attached importance to astronomical events, some—such as the Hindus and the Maya—developed elaborate systems for predicting terrestrial events from celestial observations. Western astrology, one of the oldest astrological systems still in use, can trace its roots to 19th–17th century BCE Mesopotamia, from which it spread to Ancient Greece, the Arab world and Central and Western Europe. Contemporary Western astrology is associated with systems of horoscopes that purport to explain aspects of a person's personality and predict significant events in their lives based on the positions of celestial objects.
Throughout most of its history, astrology was considered a scholarly tradition and was common in academic circles in close relation with astronomy, alchemy and medicine. It was present in political circles and is mentioned in various works of literature, from Dante Alighieri and Geoffrey Chaucer to William Shakespeare, Lope de Vega, Calderón de la Barca. Following the end of the 19th century and the wide-scale adoption of the scientific method, astrology has been challenged on both theoretical and experimental grounds, has been shown to have no scientific validity or explanatory power. Astrology thus lost its academic and theoretical standing, common belief in it has declined. While polls have demonstrated that one quarter of American and Canadian people say they continue to believe that star and planet positions affect their lives, astrology is now recognized as a pseudoscience—a belief, incorrectly presented as scientific; the word astrology comes from the early Latin word astrologia, which derives from the Greek ἀστρολογία—from ἄστρον astron and -λογία -logia.
Astrologia passed into meaning'star-divination' with astronomia used for the scientific term. Many cultures have attached importance to astronomical events, the Indians and Maya developed elaborate systems for predicting terrestrial events from celestial observations. In the West, astrology most consists of a system of horoscopes purporting to explain aspects of a person's personality and predict future events in their life based on the positions of the sun and other celestial objects at the time of their birth; the majority of professional astrologers rely on such systems. Astrology has been dated to at least the 2nd millennium BCE, with roots in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communications. A form of astrology was practised in the first dynasty of Mesopotamia. Vedāṅga Jyotiṣa, is one of earliest known Hindu texts on astrology; the text is dated between 1400 BCE to final centuries BCE by various scholars according to astronomical and linguistic evidences.
Chinese astrology was elaborated in the Zhou dynasty. Hellenistic astrology after 332 BCE mixed Babylonian astrology with Egyptian Decanic astrology in Alexandria, creating horoscopic astrology. Alexander the Great's conquest of Asia allowed astrology to spread to Ancient Rome. In Rome, astrology was associated with'Chaldean wisdom'. After the conquest of Alexandria in the 7th century, astrology was taken up by Islamic scholars, Hellenistic texts were translated into Arabic and Persian. In the 12th century, Arabic texts were translated into Latin. Major astronomers including Tycho Brahe, Johannes Kepler and Galileo practised as court astrologers. Astrological references appear in literature in the works of poets such as Dante Alighieri and Geoffrey Chaucer, of playwrights such as Christopher Marlowe and William Shakespeare. Throughout most of its history, astrology was considered a scholarly tradition, it was accepted in political and academic contexts, was connected with other studies, such as astronomy, alchemy and medicine.
At the end of the 17th century, new scientific concepts in astronomy and physics called astrology into question. Astrology thus lost its academic and theoretical standing, common belief in astrology has declined. Astrology, in its broadest sense, is the search for meaning in the sky. Early evidence for humans making conscious attempts to measure and predict seasonal changes by reference to astronomical cycles, appears as markings on bones and cave walls, which show that lunar cycles were being noted as early as 25,000 years ago; this was a first step towards recording the Moon's influence upon tides and rivers, towards organising a communal calendar. Farmers addressed agricultural needs with increasing knowledge of the constellations that appear in the different seasons—and used the rising of particular star-groups to herald annual floods or seasonal activities. By the 3rd millennium BCE, civilisations had sophisticated awareness of celestial cycles, may have oriented temples in alignment with heliacal risings of the stars.
Scattered evidence suggests that the oldest known astrological references are copies of texts made in the ancient world. The Venus tablet of Ammisaduqa is thought to be compiled in Babylon around 1700 BCE. A scroll documenting an early use of electional astrology is doubtfully ascribed to the reign of the Sumerian ruler Gud