129-720: The Halley Armada is the name of a series of space probes, five of which were successful, sent to examine Halley's Comet during its 1986 sojourn through the inner Solar System, connected with apparition "1P/1982 U1" . The armada included one probe from the European Space Agency , two probes that were joint projects between the Soviet Union and France and two probes from the Institute of Space and Astronautical Science in Japan . Notably, NASA did not contribute
258-422: A peanut , a potato , or an avocado . Its mass is roughly 2.2 × 10 kg, with an average density of about 0.55 grams per cubic centimetre (0.32 oz/cu in). The low density indicates that it is made of a large number of small pieces, held together very loosely, forming a structure known as a rubble pile . Ground-based observations of coma brightness suggested that Halley's rotation period
387-551: A spacecraft , Giotto , providing the first observational data on the structure of a comet nucleus and the mechanism of coma and tail formation. These observations supported a number of longstanding hypotheses about comet construction, particularly Fred Whipple 's "dirty snowball" model, which correctly predicted that Halley would be composed of a mixture of volatile ices —such as water , carbon dioxide , ammonia —and dust . The missions also provided data that substantially reformed and reconfigured these ideas; for instance, it
516-583: A "comet-star" appeared in the sky in the year 1067 (the chronicle is erroneous, as the event occurred in 1066, and by Robert he means William). The Emperor Constantine Ducas died in the month of May, and his son Michael received the Empire. And in this year there appeared a comet star, and the Norman count Robert [sic] fought a battle with Harold, King of the English, and Robert was victorious and became king over
645-535: A "long Renaissance" may put its beginning in the 14th century and its end in the 17th century. The traditional view focuses more on the Renaissance's early modern aspects and argues that it was a break from the past, but many historians today focus more on its medieval aspects and argue that it was an extension of the Middle Ages. The beginnings of the period—the early Renaissance of the 15th century and
774-464: A German bishop visiting north Italy during the 12th century, noticed a widespread new form of political and social organization, observing that Italy appeared to have exited from feudalism so that its society was based on merchants and commerce. Linked to this was anti-monarchical thinking, represented in the famous early Renaissance fresco cycle The Allegory of Good and Bad Government by Ambrogio Lorenzetti (painted 1338–1340), whose strong message
903-406: A German farmer and amateur astronomer. It did not pass through its perihelion until 13 March 1759, the attraction of Jupiter and Saturn having caused a delay of 618 days. This effect was computed before its return (with a one-month error to 13 April) by a team of three French mathematicians, Alexis Clairaut , Joseph Lalande , and Nicole-Reine Lepaute . The confirmation of the comet's return
1032-486: A Sanskrit poet and biographer to the Sultans of Kashmir. He read the apparition as a cometary portent of doom foreshadowing the imminent fall of Sultan Zayn al-Abidin (AD 1418/1420–1470). After witnessing a bright light in the sky which most historians have identified as Halley's Comet, Zara Yaqob , Emperor of Ethiopia from 1434 to 1468, founded the city of Debre Berhan (tr. City of Light) and made it his capital for
1161-452: A circle and 1 being a parabolic trajectory ). The perihelion, the point in the comet's orbit when it is nearest the Sun, is 0.59 au (88 million km ). This is between the orbits of Mercury and Venus . Its aphelion , or farthest distance from the Sun, is 35 au (5.2 billion km), roughly the orbital distance of Pluto . Unlike the overwhelming majority of objects in
1290-465: A citizen and official, as well as a theorist and philosopher and also Quintilian . Perhaps the most succinct expression of his perspective on humanism is in a 1465 poetic work La città di vita , but an earlier work, Della vita civile , is more wide-ranging. Composed as a series of dialogues set in a country house in the Mugello countryside outside Florence during the plague of 1430, Palmieri expounds on
1419-404: A combination of reasoning and empirical evidence . Humanist education was based on the programme of Studia Humanitatis , the study of five humanities: poetry , grammar , history , moral philosophy , and rhetoric . Although historians have sometimes struggled to define humanism precisely, most have settled on "a middle of the road definition... the movement to recover, interpret, and assimilate
SECTION 10
#17327730750621548-455: A comet appeared suspended over Rome for several days portending the death of Marcus Vipsanius Agrippa in that year. Halley's appearance in 12 BC, only a few years distant from the conventionally assigned date of the birth of Jesus Christ , has led some theologians and astronomers to suggest that it might explain the biblical story of the Star of Bethlehem . There are other explanations for
1677-518: A cultural rebirth at the close of the Middle Ages and rise of the Modern world. One of the distinguishing features of Renaissance art was its development of highly realistic linear perspective. Giotto di Bondone (1267–1337) is credited with first treating a painting as a window into space, but it was not until the demonstrations of architect Filippo Brunelleschi (1377–1446) and the subsequent writings of Leon Battista Alberti (1404–1472) that perspective
1806-553: A faster propagation of more widely distributed ideas. In the first period of the Italian Renaissance , humanists favored the study of humanities over natural philosophy or applied mathematics , and their reverence for classical sources further enshrined the Aristotelian and Ptolemaic views of the universe. Writing around 1450, Nicholas of Cusa anticipated the heliocentric worldview of Copernicus , but in
1935-444: A list of 24 comet observations, he calculated that the orbital elements of a second comet that had appeared in 1682 were nearly the same as those of two comets that had appeared in 1531 (observed by Petrus Apianus ) and 1607 (observed by Johannes Kepler ). Halley thus concluded that all three comets were, in fact, the same object returning about every 76 years, a period that has since been found to vary between 72 and 80 years. After
2064-493: A love of books. In some cases, cultivated library builders were also committed to offering others the opportunity to use their collections. Prominent aristocrats and princes of the Church created great libraries for the use of their courts, called "court libraries", and were housed in lavishly designed monumental buildings decorated with ornate woodwork, and the walls adorned with frescoes (Murray, Stuart A.P.). Renaissance art marks
2193-438: A member of a new population of small Solar System bodies that serves as the source of Halley-type comets. Halley has probably been in its current orbit for 16,000–200,000 years, although it is not possible to numerically integrate its orbit for more than a few tens of apparitions, and close approaches before 837 AD can only be verified from recorded observations. The non-gravitational effects can be crucial; as Halley approaches
2322-475: A particular comet. The Florentine chronicler Giovanni Villani wrote that the comet left "great trails of fumes behind", and that it remained visible from September 1301 until January 1302. It was seen by the artist Giotto di Bondone , who represented the Star of Bethlehem as a fire-coloured comet in the Nativity section of his Arena Chapel cycle, completed in 1305. Giotto's depiction includes details of
2451-532: A passage in the Babylonian Talmud , tractate Horayot that refers to "a star which appears once in seventy years that makes the captains of the ships err". Others doubt this idea based on historical considerations about the exact timing of this alleged observation, and suggest it refers to other astronomical phenomena. Researchers in 1981 attempting to calculate the past orbits of Halley by numerical integration starting from accurate observations in
2580-432: A perfect mind and body, which could be attained with education. The purpose of humanism was to create a universal man whose person combined intellectual and physical excellence and who was capable of functioning honorably in virtually any situation. This ideology was referred to as the uomo universale , an ancient Greco-Roman ideal. Education during the Renaissance was mainly composed of ancient literature and history as it
2709-403: A philosophical fashion. Science and art were intermingled in the early Renaissance, with polymath artists such as Leonardo da Vinci making observational drawings of anatomy and nature. Leonardo set up controlled experiments in water flow, medical dissection, and systematic study of movement and aerodynamics, and he devised principles of research method that led Fritjof Capra to classify him as
SECTION 20
#17327730750622838-516: A probe to the Halley Armada. Without the measurements from the other space probes, Giotto's closest distance would have been 4,000 km instead of the 596 km achieved. Other space probes had their instruments examining Halley's Comet: The Space Shuttle Challenger , on its launch on January 28, 1986, was carrying SPARTAN-203 with the mission to make observations of Halley's Comet. STS-51L failed to reach orbit , resulting in
2967-552: A quarter of that of the Moon . Halley came within 0.10 au of Earth at that time. This appearance of the comet is also noted in the Anglo-Saxon Chronicle . Eilmer of Malmesbury may have seen Halley in 989 and 1066, as recorded by William of Malmesbury : Not long after, a comet, portending (they say) a change in governments, appeared, trailing its long flaming hair through the empty sky: concerning which there
3096-499: A rough estimate of the perturbations the comet would sustain from the gravitational attraction of the planets, he predicted its return for 1758. While he had personally observed the comet around perihelion in September 1682, Halley died in 1742 before he could observe its predicted return. Halley's prediction of the comet's return proved to be correct, although it was not seen until 25 December 1758, by Johann Georg Palitzsch ,
3225-531: A wall in the form of pilasters. One of the first buildings to use pilasters as an integrated system was in the Old Sacristy (1421–1440) by Brunelleschi. Arches, semi-circular or (in the Mannerist style) segmental, are often used in arcades, supported on piers or columns with capitals. There may be a section of entablature between the capital and the springing of the arch. Alberti was one of the first to use
3354-459: A wide range of writers. Classical texts could be found alongside humanist writings. These informal associations of intellectuals profoundly influenced Renaissance culture. An essential tool of Renaissance librarianship was the catalog that listed, described, and classified a library's books. Some of the richest "bibliophiles" built libraries as temples to books and knowledge. A number of libraries appeared as manifestations of immense wealth joined with
3483-493: Is about 4%, meaning that it reflects only 4% of the sunlight hitting it – about what one would expect for coal. Thus, despite astronomers predicting that Halley would have an albedo of about 0.17 (roughly equivalent to bare soil), Halley's Comet is in fact pitch black. The "dirty ices" on the surface sublime at temperatures between 170 K (−103 °C) in sections of higher albedo to 220 K (−53 °C) at low albedo; Vega 1 found Halley's surface temperature to be in
3612-581: Is about the virtues of fairness, justice, republicanism and good administration. Holding both Church and Empire at bay, these city republics were devoted to notions of liberty. Skinner reports that there were many defences of liberty such as the Matteo Palmieri (1406–1475) celebration of Florentine genius not only in art, sculpture and architecture, but "the remarkable efflorescence of moral, social and political philosophy that occurred in Florence at
3741-566: Is associated with two meteor showers : the Eta Aquariids in early May, and the Orionids in late October. Halley is classified as a periodic or short-period comet : one with an orbit lasting 200 years or less. This contrasts it with long-period comets, whose orbits last for thousands of years. Periodic comets have an average inclination to the ecliptic of only ten degrees, and an orbital period of just 6.5 years, so Halley's orbit
3870-458: Is atypical. Most short-period comets (those with orbital periods shorter than 20 years and inclinations of 30 degrees or less) are called Jupiter-family comets. Those resembling Halley, with orbital periods of between 20 and 200 years and inclinations extending from zero to more than 90 degrees, are called Halley-type comets. As of 2024 , 105 Halley-type comets have been observed, compared with 816 identified Jupiter-family comets. The orbits of
3999-448: Is believed by some Sikh scholars to be a reference to Halley's appearance in 1531. Halley's periodic returns have been subject to scientific investigation since the 16th century. The three apparitions from 1531 to 1682 were noted by Edmond Halley, enabling him to predict it would return. One key breakthrough occurred when Halley talked with Newton about his ideas of the laws of motion. Newton also helped Halley get John Flamsteed's data on
Halley Armada - Misplaced Pages Continue
4128-474: Is consistently visible to the naked eye from Earth , appearing every 72–80 years, though with the majority of recorded apparations (25 of 30) occuring after 75-77 years. It last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061. Officially designated 1P/Halley , it is also commonly called Comet Halley , or sometimes simply Halley . Halley's periodic returns to
4257-653: Is estimated to be about 10 million years. The dynamics of its orbit can be approximately described by a two-dimensional symplectic map , known as the Kepler map , a solution to the restricted three-body problem for highly eccentric orbits. Based on records from the 1910 apparition, David Hughes calculated in 1985 that Halley's nucleus has been reduced in mass by 80 to 90% over the last 2,000 to 3,000 revolutions, and that it will most likely disappear completely after another 2,300 perihelion passages. More recent work suggests that Halley will evaporate, or split in two, within
4386-449: Is far more active than the night side. Spacecraft observations showed that the gases ejected from the nucleus were 80% water vapour, 17% carbon monoxide and 3–4% carbon dioxide, with traces of hydrocarbons although more recent sources give a value of 10% for carbon monoxide and also include traces of methane and ammonia . The dust particles were found to be primarily a mixture of carbon–hydrogen–oxygen–nitrogen (CHON) compounds common in
4515-639: Is now understood that the surface of Halley is largely composed of dusty, non-volatile materials, and that only a small portion of it is icy. Comet Halley is usually pronounced / ˈ h æ l i / , rhyming with valley , or sometimes / ˈ h eɪ l i / , rhyming with daily . As to the surname Halley, Colin Ronan , one of Edmond Halley's biographers, preferred / ˈ h ɔː l i / , rhyming with crawly . Spellings of Halley's name during his lifetime included Hailey , Haley , Hayley , Halley , Haly , Hawley , and Hawly , so its contemporary pronunciation
4644-546: Is that the devastation in Florence caused by the Black Death , which hit Europe between 1348 and 1350, resulted in a shift in the world view of people in 14th century Italy. Italy was particularly badly hit by the plague, and it has been speculated that the resulting familiarity with death caused thinkers to dwell more on their lives on Earth, rather than on spirituality and the afterlife . It has also been argued that
4773-509: Is to understand it rationally. A critical contribution to Italian Renaissance humanism, Giovanni Pico della Mirandola wrote De hominis dignitate ( Oration on the Dignity of Man , 1486), a series of theses on philosophy, natural thought, faith, and magic defended against any opponent on the grounds of reason. In addition to studying classical Latin and Greek, Renaissance authors also began increasingly to use vernacular languages; combined with
4902-556: Is uncertain, but the version rhyming with valley seems to be preferred by current bearers of the surname. Halley was the first comet to be recognised as periodic. Until the Renaissance , the philosophical consensus on the nature of comets, promoted by Aristotle , was that they were disturbances in Earth's atmosphere. This idea was disproven in 1577 by Tycho Brahe , who used parallax measurements to show that comets must lie beyond
5031-477: The longue durée , have instead focused on the continuity between the two eras, which are linked, as Panofsky observed, "by a thousand ties". The word has also been extended to other historical and cultural movements, such as the Carolingian Renaissance (8th and 9th centuries), Ottonian Renaissance (10th and 11th century), and the Renaissance of the 12th century . The Renaissance
5160-911: The High Middle Ages in Western Europe and in the Islamic Golden Age (normally in translation), but Greek literary, oratorical and historical works (such as Homer , the Greek dramatists, Demosthenes and Thucydides ) were not studied in either the Latin or medieval Islamic worlds ; in the Middle Ages these sorts of texts were only studied by Byzantine scholars. Some argue that the Timurid Renaissance in Samarkand and Herat , whose magnificence toned with Florence as
5289-518: The Kuiper belt , a flat disc of icy debris between 30 au (Neptune's orbit) and 50 au from the Sun (in the scattered disc ). Another point of origin for the Halley-type comets was proposed in 2008, when a trans-Neptunian object with a retrograde orbit similar to Halley's was discovered, 2008 KV 42 , whose orbit takes it from just outside that of Uranus to twice the distance of Pluto. It may be
Halley Armada - Misplaced Pages Continue
5418-747: The Late Middle Ages have led some to theorize that its unusual social climate allowed the emergence of a rare cultural efflorescence. Italy did not exist as a political entity in the early modern period. Instead, it was divided into smaller city-states and territories: the Neapolitans controlled the south, the Florentines and the Romans at the center, the Milanese and the Genoese to
5547-765: The Levant . Their translations and commentaries on these ideas worked their way through the Arab West into Iberia and Sicily , which became important centers for this transmission of ideas. Between the 11th and 13th centuries, many schools dedicated to the translation of philosophical and scientific works from Classical Arabic to Medieval Latin were established in Iberia, most notably the Toledo School of Translators . This work of translation from Islamic culture, though largely unplanned and disorganized, constituted one of
5676-500: The Moon . Many were still unconvinced that comets orbited the Sun, and assumed instead that they must follow straight paths through the Solar System. In 1687, Sir Isaac Newton published his Philosophiæ Naturalis Principia Mathematica , in which he outlined his laws of gravity and motion. His work on comets was decidedly incomplete. Although he had suspected that two comets that had appeared in succession in 1680 and 1681 were
5805-499: The Pisa Baptistry , demonstrates that classical models influenced Italian art before the Renaissance took root as a literary movement. Applied innovation extended to commerce. At the end of the 15th century, Luca Pacioli published the first work on bookkeeping , making him the founder of accounting . The rediscovery of ancient texts and the invention of the printing press in about 1440 democratized learning and allowed
5934-542: The Renaissance Papacy , and Naples . From Italy, the Renaissance spread throughout Europe and also to American, African and Asian territories ruled by the European colonial powers of the time or where Christian missionaries were active. The Renaissance has a long and complex historiography , and in line with general skepticism of discrete periodizations, there has been much debate among historians reacting to
6063-813: The crisis of the Late Middle Ages and conventionally ends by the 1600s with the waning of humanism , and the advents of the Reformation and Counter-Reformation , and in art the Baroque period. It had a different period and characteristics in different regions, such as the Italian Renaissance, the Northern Renaissance , the Spanish Renaissance , etc. In addition to the standard periodization, proponents of
6192-435: The inner Solar System have been observed and recorded by astronomers around the world since at least 240 BC, but it was not until 1705 that the English astronomer Edmond Halley understood that these appearances were re-appearances of the same comet. As a result of this discovery, the comet is named after Halley. During its 1986 visit to the inner Solar System, Halley's Comet became the first comet to be observed in detail by
6321-534: The rest of Italy and later throughout Europe. The term rinascita ("rebirth") first appeared in Lives of the Artists ( c. 1550 ) by Giorgio Vasari , while the corresponding French word renaissance was adopted into English as the term for this period during the 1830s. The Renaissance's intellectual basis was founded in its version of humanism , derived from the concept of Roman humanitas and
6450-592: The "father of modern science". Other examples of Da Vinci's contribution during this period include machines designed to saw marbles and lift monoliths, and new discoveries in acoustics, botany, geology, anatomy, and mechanics. A suitable environment had developed to question classical scientific doctrine. The discovery in 1492 of the New World by Christopher Columbus challenged the classical worldview. The works of Ptolemy (in geography) and Galen (in medicine) were found to not always match everyday observations. As
6579-418: The 12th century , who had focused on studying Greek and Arabic works of natural sciences, philosophy, and mathematics, rather than on such cultural texts. In the revival of neoplatonism , Renaissance humanists did not reject Christianity ; on the contrary, many of the Renaissance's greatest works were devoted to it, and the Church patronized many works of Renaissance art. But a subtle shift took place in
SECTION 50
#17327730750626708-404: The 14th century with a Latin phase, when Renaissance scholars such as Petrarch , Coluccio Salutati (1331–1406), Niccolò de' Niccoli (1364–1437), and Poggio Bracciolini (1380–1459) scoured the libraries of Europe in search of works by such Latin authors as Cicero , Lucretius , Livy , and Seneca . By the early 15th century, the bulk of the surviving such Latin literature had been recovered;
6837-552: The 15th and 16th centuries. It marked the transition from the Middle Ages to modernity and was characterized by an effort to revive and surpass the ideas and achievements of classical antiquity . Associated with great social change in most fields and disciplines, including art , architecture , politics, literature , exploration and science , the Renaissance was first centered in the Republic of Florence , then spread to
6966-424: The 1682 apparition. By studying data on the 1531, 1607, and 1682 comets, he came to the conclusion these were the same comet, and presented his findings in 1696. Renaissance The Renaissance ( UK : / r ɪ ˈ n eɪ s ən s / rin- AY -sənss , US : / ˈ r ɛ n ə s ɑː n s / REN -ə-sahnss ) is a period of history and a European cultural movement covering
7095-435: The 19th-century glorification of the "Renaissance" and individual cultural heroes as "Renaissance men", questioning the usefulness of Renaissance as a term and as a historical delineation. Some observers have questioned whether the Renaissance was a cultural "advance" from the Middle Ages, instead seeing it as a period of pessimism and nostalgia for classical antiquity , while social and economic historians, especially of
7224-535: The 1st-century writer Vitruvius and the flourishing discipline of mathematics, Brunelleschi formulated the Renaissance style that emulated and improved on classical forms. His major feat of engineering was building the dome of Florence Cathedral . Another building demonstrating this style is the Basilica of Sant'Andrea, Mantua , built by Alberti. The outstanding architectural work of the High Renaissance
7353-520: The Black Death prompted a new wave of piety, manifested in the sponsorship of religious works of art. However, this does not fully explain why the Renaissance occurred specifically in Italy in the 14th century. The Black Death was a pandemic that affected all of Europe in the ways described, not only Italy. The Renaissance's emergence in Italy was most likely the result of the complex interaction of
7482-730: The Convent of San Donato in Scopeto in Florence. The Renaissance was certainly underway before Lorenzo de' Medici came to power – indeed, before the Medici family itself achieved hegemony in Florentine society. In some ways, Renaissance humanism was not a philosophy but a method of learning. In contrast to the medieval scholastic mode, which focused on resolving contradictions between authors, Renaissance humanists would study ancient texts in their original languages and appraise them through
7611-440: The Greek phase of Renaissance humanism was under way, as Western European scholars turned to recovering ancient Greek literary, historical, oratorical and theological texts. Unlike with Latin texts, which had been preserved and studied in Western Europe since late antiquity, the study of ancient Greek texts was very limited in medieval Western Europe. Ancient Greek works on science, mathematics, and philosophy had been studied since
7740-534: The Halley-type comets suggest that they were originally long-period comets whose orbits were perturbed by the gravity of the giant planets and directed into the inner Solar System. If Halley was once a long-period comet, it is likely to have originated in the Oort cloud , a sphere of cometary bodies around 20,000–50,000 au from the Sun. Conversely the Jupiter-family comets are generally believed to originate in
7869-705: The Islamic steps of Ibn Khaldun . Pico della Mirandola wrote the "manifesto" of the Renaissance, the Oration on the Dignity of Man , a vibrant defence of thinking. Matteo Palmieri (1406–1475), another humanist, is most known for his work Della vita civile ("On Civic Life"; printed 1528), which advocated civic humanism , and for his influence in refining the Tuscan vernacular to the same level as Latin. Palmieri drew on Roman philosophers and theorists, especially Cicero , who, like Palmieri, lived an active public life as
SECTION 60
#17327730750627998-521: The Italian Proto-Renaissance from around 1250 or 1300—overlap considerably with the Late Middle Ages , conventionally dated to c. 1350–1500 , and the Middle Ages themselves were a long period filled with gradual changes, like the modern age; as a transitional period between both, the Renaissance has close similarities to both, especially the late and early sub-periods of either. The Renaissance began in Florence , one of
8127-466: The Latin literary, historical, and oratorical texts of antiquity , while the fall of Constantinople (1453) generated a wave of émigré Greek scholars bringing precious manuscripts in ancient Greek , many of which had fallen into obscurity in the West. It was in their new focus on literary and historical texts that Renaissance scholars differed so markedly from the medieval scholars of the Renaissance of
8256-568: The New Testament promoted by humanists Lorenzo Valla and Erasmus , helped pave the way for the Reformation . Well after the first artistic return to classicism had been exemplified in the sculpture of Nicola Pisano , Florentine painters led by Masaccio strove to portray the human form realistically, developing techniques to render perspective and light more naturally. Political philosophers , most famously Niccolò Machiavelli , sought to describe political life as it really was, that
8385-644: The Popes [ la ] that, A hairy and fiery star having then made its appearance for several days, the mathematicians declared that there would follow grievous pestilence, dearth and some great calamity. Calixtus, to avert the wrath of God, ordered supplications that if evils were impending for the human race He would turn all upon the Turks, the enemies of the Christian name. He likewise ordered, to move God by continual entreaty, that notice should be given by
8514-474: The Reformation and Counter-Reformation clashed, the Northern Renaissance showed a decisive shift in focus from Aristotelean natural philosophy to chemistry and the biological sciences (botany, anatomy, and medicine). The willingness to question previously held truths and search for new answers resulted in a period of major scientific advancements. Some view this as a " scientific revolution ", heralding
8643-546: The Renaissance quite precisely; one proposed starting point is 1401, when the rival geniuses Lorenzo Ghiberti and Filippo Brunelleschi competed for the contract to build the bronze doors for the Baptistery of the Florence Cathedral (Ghiberti won). Others see more general competition between artists and polymaths such as Brunelleschi, Ghiberti, Donatello , and Masaccio for artistic commissions as sparking
8772-481: The Solar System, Halley's orbit is retrograde ; it orbits the Sun in the opposite direction to the planets, or, clockwise from above the Sun's north pole. The orbit is inclined by 18° to the ecliptic , with much of it lying south of the ecliptic. This is usually represented as 162°, to account for Halley's retrograde orbit. The 1910 passage was at a relative velocity of 70.56 km/s (157,800 mph). Because its orbit comes close to Earth's in two places, Halley
8901-631: The Sun on August 6 in 87 BC" as the comet would have been a "most recordable event"; for ancient Armenians it could have heralded the New Era of the brilliant King of Kings. The apparition of 12 BC was recorded in the Book of Han by Chinese astronomers of the Han dynasty who tracked it from August through October. It passed within 0.16 au of Earth. According to the Roman historian Cassius Dio ,
9030-487: The Sun, it expels jets of sublimating gas from its surface, which knock it very slightly off its orbital path. These orbital changes cause delays in its perihelion passage of four days on average. In 1989, Boris Chirikov and Vitold Vecheslavov performed an analysis of 46 apparitions of Halley's Comet taken from historical records and computer simulations, which showed that its dynamics were chaotic and unpredictable on long timescales. Halley's projected dynamical lifetime
9159-458: The above factors. The plague was carried by fleas on sailing vessels returning from the ports of Asia, spreading quickly due to lack of proper sanitation: the population of England , then about 4.2 million, lost 1.4 million people to the bubonic plague . Florence's population was nearly halved in the year 1347. As a result of the decimation in the populace the value of the working class increased, and commoners came to enjoy more freedom. To answer
9288-532: The arch on a monumental. Renaissance vaults do not have ribs; they are semi-circular or segmental and on a square plan, unlike the Gothic vault, which is frequently rectangular. Renaissance artists were not pagans, although they admired antiquity and kept some ideas and symbols of the medieval past. Nicola Pisano (c. 1220 – c. 1278) imitated classical forms by portraying scenes from the Bible. His Annunciation , from
9417-758: The artist. Halley's 1378 appearance is recorded in the Annales Mediolanenses as well as in East Asian sources. In 1456, the year of Halley's next apparition, the Ottoman Empire invaded the Kingdom of Hungary , culminating in the siege of Belgrade in July of that year. In a papal bull , Pope Callixtus III ordered special prayers be said for the city's protection. In 1470, the humanist scholar Bartolomeo Platina wrote in his Lives of
9546-615: The beginning of the modern age, others as an acceleration of a continuous process stretching from the ancient world to the present day. Significant scientific advances were made during this time by Galileo Galilei , Tycho Brahe , and Johannes Kepler . Copernicus, in De revolutionibus orbium coelestium ( On the Revolutions of the Heavenly Spheres ), posited that the Earth moved around the Sun. De humani corporis fabrica ( On
9675-619: The bells to call the faithful at midday to aid by their prayers those engaged in battle with the Turk. Platina's account is not mentioned in official records. In the 18th century, a Frenchman further embellished the story, in anger at the Church, by claiming that the Pope had "excommunicated" the comet, though this story was most likely his own invention. Halley's apparition of 1456 was also witnessed in Kashmir and depicted in great detail by Śrīvara,
9804-469: The center of a cultural rebirth, were linked to the Ottoman Empire , whose conquests led to the migration of Greek scholars to Italian cities. One of the greatest achievements of Renaissance scholars was to bring this entire class of Greek cultural works back into Western Europe for the first time since late antiquity. Muslim logicians, most notably Avicenna and Averroes , had inherited Greek ideas after they had invaded and conquered Egypt and
9933-506: The coma, a sweeping tail, and the central condensation. According to the art historian Roberta Olson , it is much more accurate than other contemporary descriptions, and was not equaled in painting until the 19th century. Olson's identification of Halley's Comet in Giotto's Adoration of the Magi is what inspired the European Space Agency to name their mission to the comet Giotto , after
10062-629: The comet was seen in England and thought to be an omen : later that year Harold II of England died at the Battle of Hastings and William the Conqueror claimed the throne. The comet is represented on the Bayeux Tapestry and described in the tituli as a star. Surviving accounts from the period describe it as appearing to be four times the size of Venus , and shining with a light equal to
10191-687: The creativity of the Renaissance. Yet it remains much debated why the Renaissance began in Italy, and why it began when it did. Accordingly, several theories have been put forward to explain its origins. Peter Rietbergen posits that various influential Proto-Renaissance movements started from roughly 1300 onwards across many regions of Europe . In stark contrast to the High Middle Ages , when Latin scholars focused almost entirely on studying Greek and Arabic works of natural science, philosophy and mathematics, Renaissance scholars were most interested in recovering and studying Latin and Greek literary, historical, and oratorical texts. Broadly speaking, this began in
10320-473: The first evidence in support of Fred Whipple 's "dirty snowball" hypothesis for comet construction; Whipple postulated that comets are icy objects warmed by the Sun as they approach the inner Solar System, causing ices on their surfaces to sublime (change directly from a solid to a gas), and jets of volatile material to burst outward, creating the coma. Giotto showed that this model was broadly correct, though with modifications. Halley's albedo , for instance,
10449-470: The great European states (France and Spain) were absolute monarchies , and others were under direct Church control, the independent city-republics of Italy took over the principles of capitalism invented on monastic estates and set off a vast unprecedented Commercial Revolution that preceded and financed the Renaissance. Historian Leon Poliakov offers a critical view in his seminal study of European racist thought: The Aryan Myth . According to Poliakov,
10578-658: The greatest transmissions of ideas in history. The movement to reintegrate the regular study of Greek literary, historical, oratorical, and theological texts back into the Western European curriculum is usually dated to the 1396 invitation from Coluccio Salutati to the Byzantine diplomat and scholar Manuel Chrysoloras (c. 1355–1415) to teach Greek in Florence. This legacy was continued by a number of expatriate Greek scholars, from Basilios Bessarion to Leo Allatius . The unique political structures of Italy during
10707-438: The height of the epidemic due to the chaotic conditions in the city, but a small group of officials was appointed to conduct the affairs of the city, which ensured continuity of government. It has long been a matter of debate why the Renaissance began in Florence , and not elsewhere in Italy. Scholars have noted several features unique to Florentine cultural life that may have caused such a cultural movement. Many have emphasized
10836-651: The historical record is a description from 240 BC, in the Chinese chronicle Records of the Grand Historian or Shiji , which describes a comet that appeared in the east and moved north. The only surviving record of the 164 BC apparition is found on two fragmentary Babylonian tablets, which were rediscovered in August 1984 in the collection of the British Museum . The apparition of 87 BC
10965-493: The immune system, leaving young children without a fighting chance. Children in city dwellings were more affected by the spread of disease than the children of the wealthy. The Black Death caused greater upheaval to Florence's social and political structure than later epidemics. Despite a significant number of deaths among members of the ruling classes, the government of Florence continued to function during this period. Formal meetings of elected representatives were suspended during
11094-413: The increased need for labor, workers traveled in search of the most favorable position economically. The demographic decline due to the plague had economic consequences: the prices of food dropped and land values declined by 30–40% in most parts of Europe between 1350 and 1400. Landholders faced a great loss, but for ordinary men and women it was a windfall. The survivors of the plague found not only that
11223-511: The introduction of the printing press , this allowed many more people access to books, especially the Bible. In all, the Renaissance can be viewed as an attempt by intellectuals to study and improve the secular and worldly, both through the revival of ideas from antiquity and through novel approaches to thought. Political philosopher Hans Kohn describes it as an age where "Men looked for new foundations"; some like Erasmus and Thomas More envisioned new reformed spiritual foundations, others. in
11352-464: The language, literature, learning and values of ancient Greece and Rome". Above all, humanists asserted "the genius of man ... the unique and extraordinary ability of the human mind". Humanist scholars shaped the intellectual landscape throughout the early modern period. Political philosophers such as Niccolò Machiavelli and Thomas More revived the ideas of Greek and Roman thinkers and applied them in critiques of contemporary government, following
11481-538: The many states of Italy . Various theories have been proposed to account for its origins and characteristics, focusing on a variety of factors, including Florence's social and civic peculiarities at the time: its political structure, the patronage of its dominant family, the Medici , and the migration of Greek scholars and their texts to Italy following the fall of Constantinople to the Ottoman Empire . Other major centers were Venice , Genoa , Milan , Rome during
11610-525: The next few tens of thousands of years, or will be ejected from the Solar System within a few hundred thousand years. The Giotto and Vega missions gave planetary scientists their first view of Halley's surface and structure. The nucleus is a conglomerate of ices and dust , often referred to as a "dirty snowball". Like all comets, as Halley nears the Sun, its volatile compounds (those with low boiling points, such as water , carbon monoxide , carbon dioxide and other ices) begin to sublimate from
11739-661: The north and west respectively, and the Venetians to the north east. 15th-century Italy was one of the most urbanized areas in Europe. Many of its cities stood among the ruins of ancient Roman buildings; it seems likely that the classical nature of the Renaissance was linked to its origin in the Roman Empire's heartland. Historian and political philosopher Quentin Skinner points out that Otto of Freising (c. 1114–1158),
11868-585: The outer Solar System, and silicates, such as are found in terrestrial rocks. The dust particles ranged in size down to the limits of detection (≈0.001 μm). The ratio of deuterium to hydrogen in the water released by Halley was initially thought to be similar to that found in Earth's ocean water, suggesting that Halley-type comets may have delivered water to Earth in the distant past. Subsequent observations showed Halley's deuterium ratio to be far higher than that found in Earth's oceans, making such comets unlikely sources for Earth's water. Giotto provided
11997-584: The paintings of Giotto . As a cultural movement, the Renaissance encompassed innovative flowering of literary Latin and an explosion of vernacular literatures , beginning with the 14th-century resurgence of learning based on classical sources, which contemporaries credited to Petrarch ; the development of linear perspective and other techniques of rendering a more natural reality in painting; and gradual but widespread educational reform . It saw myriad artistic developments and contributions from such polymaths as Leonardo da Vinci and Michelangelo , who inspired
12126-438: The people of the English. The 1145 apparition may have been recorded by the monk Eadwine . According to legend, Genghis Khan was inspired to turn his conquests toward Europe by the westward-seeming trajectory of the 1222 apparition. In Korea, the comet was reportedly visible during the daylight on 9 September 1222. The 1301 apparition was visually spectacular, and may be the first that resulted in convincing portraits of
12255-522: The phenomenon, such as planetary conjunctions , and there are also records of other comets that appeared closer to the date of Jesus's birth. If Yehoshua ben Hananiah 's reference to "a star which arises once in seventy years and misleads the sailors" refers to Halley's Comet, he can only have witnessed the 66 AD appearance. Another possible report comes from Jewish historian Josephus , who wrote that in 66 AD "The signs ... were so evident, and did so plainly foretell their future desolation ... there
12384-419: The prevailing cultural conditions at the time. Lorenzo de' Medici (1449–1492) was the catalyst for an enormous amount of arts patronage, encouraging his countrymen to commission works from the leading artists of Florence, including Leonardo da Vinci , Sandro Botticelli , and Michelangelo Buonarroti . Works by Neri di Bicci , Botticelli, Leonardo, and Filippino Lippi had been commissioned additionally by
12513-459: The prices of food were cheaper but also that lands were more abundant, and many of them inherited property from their dead relatives. The spread of disease was significantly more rampant in areas of poverty. Epidemics ravaged cities, particularly children. Plagues were easily spread by lice, unsanitary drinking water, armies, or by poor sanitation. Children were hit the hardest because many diseases, such as typhus and congenital syphilis , target
12642-412: The qualities of the ideal citizen. The dialogues include ideas about how children develop mentally and physically, how citizens can conduct themselves morally, how citizens and states can ensure probity in public life, and an important debate on the difference between that which is pragmatically useful and that which is honest. The humanists believed that it is important to transcend to the afterlife with
12771-435: The range 300–400 K (27–127 °C). This suggested that only 10% of Halley's surface was active, and that large portions of it were coated in a layer of dark dust that retained heat. Together, these observations suggested that Halley was in fact predominantly composed of non- volatile materials, and thus more closely resembled a "snowy dirtball" than a "dirty snowball". The first certain appearance of Halley's Comet in
12900-414: The rediscovery of classical Greek philosophy , such as that of Protagoras , who said that "man is the measure of all things". Although the invention of metal movable type sped the dissemination of ideas from the later 15th century, the changes of the Renaissance were not uniform across Europe: the first traces appear in Italy as early as the late 13th century, in particular with the writings of Dante and
13029-556: The remainder of his reign. Petrus Apianus and Girolamo Fracastoro described the comet's visit in 1531, with the former even including graphics in his publication. Through his observations, Apianus was able to prove that a comet's tail always points away from the Sun. In the Sikh scriptures of the Guru Granth Sahib , the founder of the faith Guru Nanak makes reference to " a long star that has risen " at Ang 1110, and it
13158-549: The role played by the Medici , a banking family and later ducal ruling house , in patronizing and stimulating the arts. Some historians have postulated that Florence was the birthplace of the Renaissance as a result of luck, i.e., because " Great Men " were born there by chance: Leonardo, Botticelli and Michelangelo were all born in Tuscany . Arguing that such chance seems improbable, other historians have contended that these "Great Men" were only able to rise to prominence because of
13287-496: The same comet before and after passing behind the Sun (he was later found to be correct; see Newton's Comet ), he was initially unable to completely reconcile comets into his model. Ultimately, it was Newton's friend, editor and publisher, Edmond Halley , who, in his 1705 Synopsis of the Astronomy of Comets , used Newton's new laws to calculate the gravitational effects of Jupiter and Saturn on cometary orbits. Having compiled
13416-527: The same time". Even cities and states beyond central Italy, such as the Republic of Florence at this time, were also notable for their merchant republics , especially the Republic of Venice. Although in practice these were oligarchical , and bore little resemblance to a modern democracy , they did have democratic features and were responsive states, with forms of participation in governance and belief in liberty. The relative political freedom they afforded
13545-470: The seventeenth and eighteenth centuries could not produce accurate results further back than 837 owing to a close approach to Earth in that year. It was necessary to use ancient Chinese comet observations to constrain their calculations. Halley's orbital period has varied between 74 and 80 years since 240 BC. Its orbit around the Sun is highly elliptical , with an orbital eccentricity of 0.967 (with 0 being
13674-579: The seventh of the Calends of May, on Tuesday after Little Easter, than whose light the brilliance or light of The Moon was not greater; and it was visible to all in this manner till the end of four nights afterwards." Chaco Native Americans in New Mexico may have recorded the 1066 apparition in their petroglyphs. The Italo-Byzantine chronicle of Lupus the Protospatharios mentions that
13803-708: The sky. It was recorded by astronomers in China, Japan, Germany, the Byzantine Empire, and the Middle East; Emperor Louis the Pious observed this appearance and devoted himself to prayer and penance, fearing that "by this token a change in the realm and the death of a prince are made known". In 912 AD, Halley is recorded in the Annals of Ulster , which states "A dark and rainy year. A comet appeared." In 1066,
13932-402: The solar light. Both processes are responsible for making the coma visible. As a fraction of the gas molecules in the coma are ionised by the solar ultraviolet radiation , pressure from the solar wind , a stream of charged particles emitted by the Sun, pulls the coma's ions out into a long tail , which may extend more than 100 million kilometres into space. Changes in the flow of
14061-562: The solar wind can cause disconnection events , in which the tail completely breaks off from the nucleus. Despite the vast size of its coma, Halley's nucleus is relatively small: barely 15 kilometres (9.3 mi) long, 8 kilometres (5.0 mi) wide and perhaps 8 kilometres (5.0 mi) thick. Based on a reanalysis of images taken by the Giotto and Vega spacecraft, Lamy et al. determined an effective diameter of 11 kilometres (6.8 mi). Its shape has been variously compared to that of
14190-416: The surface. This causes the comet to develop a coma , or atmosphere, at distances up to 230,000 kilometres (140,000 mi) from the nucleus. Sublimation of this dirty ice releases dust particles, which travel with the gas away from the nucleus. Gas molecules in the coma absorb solar light and then re-radiate it at different wavelengths, a phenomenon known as fluorescence , whereas dust particles scatter
14319-420: The term "Renaissance man". In politics, the Renaissance contributed to the development of the customs and conventions of diplomacy, and in science to an increased reliance on observation and inductive reasoning . The period also saw revolutions in other intellectual and social scientific pursuits, as well as the introduction of modern banking and the field of accounting. The Renaissance period started during
14448-474: The total loss of crew and vehicle. That launch failure resulted in the cancellation of dozens of subsequent shuttle missions, including the next scheduled launch, STS-61-E , planned for March 6, 1986, with a payload including the ASTRO-1 observatory, which was intended to make astronomical observations of Halley's Comet. Halley%27s Comet Halley's Comet is the only known short-period comet that
14577-421: The use of ethnic origin myths are first used by Renaissance humanists "in the service of a new born chauvinism". Many argue that the ideas characterizing the Renaissance had their origin in Florence at the turn of the 13th and 14th centuries, in particular with the writings of Dante Alighieri (1265–1321) and Petrarch (1304–1374), as well as the paintings of Giotto di Bondone (1267–1337). Some writers date
14706-476: The way that intellectuals approached religion that was reflected in many other areas of cultural life. In addition, many Greek Christian works, including the Greek New Testament, were brought back from Byzantium to Western Europe and engaged Western scholars for the first time since late antiquity. This new engagement with Greek Christian works, and particularly the return to the original Greek of
14835-506: The words of Machiavelli , una lunga sperienza delle cose moderne ed una continua lezione delle antiche (a long experience with modern life and a continuous learning from antiquity). Sociologist Rodney Stark , plays down the Renaissance in favor of the earlier innovations of the Italian city-states in the High Middle Ages , which married responsive government, Christianity and the birth of capitalism . This analysis argues that, whereas
14964-526: The works of Leonardo, Michelangelo and Raphael representing artistic pinnacles that were much imitated by other artists. Other notable artists include Sandro Botticelli , working for the Medici in Florence, Donatello , another Florentine, and Titian in Venice, among others. In the Low Countries , a particularly vibrant artistic culture developed. The work of Hugo van der Goes and Jan van Eyck
15093-565: Was a cultural movement that profoundly affected European intellectual life in the early modern period . Beginning in Italy, and spreading to the rest of Europe by the 16th century, its influence was felt in art , architecture , philosophy , literature , music , science , technology , politics, religion, and other aspects of intellectual inquiry. Renaissance scholars employed the humanist method in study, and searched for realism and human emotion in art. Renaissance humanists such as Poggio Bracciolini sought out in Europe's monastic libraries
15222-487: Was a fine saying of a monk of our monastery called Æthelmær. Crouching in terror at the sight of the gleaming star, "You've come, have you?", he said. "You've come, you source of tears to many mothers. It is long since I saw you; but as I see you now you are much more terrible, for I see you brandishing the downfall of my country." The Irish Annals of the Four Masters recorded the comet as "A star [that] appeared on
15351-508: Was a star resembling a sword, which stood over the city, and a comet, that continued a whole year". This portent was in reference to the city of Jerusalem and the First Jewish–Roman War . The 141 AD apparition was recorded in Chinese chronicles, with observations of a bluish white comet on 27 March and 16, 22 and 23 April. The 374 AD and 607 approaches each came within 0.09 au of Earth. The 451 AD apparition
15480-454: Was about 7.4 days. Images taken by the various spacecraft, along with observations of the jets and shell, suggested a period of 52 hours. Given the irregular shape of the nucleus, Halley's rotation is likely to be complex. The flyby images revealed an extremely varied topography, with hills, mountains, ridges, depressions, and at least one crater. Halley's day side (the side facing the Sun)
15609-638: Was conducive to academic and artistic advancement. Likewise, the position of Italian cities such as Venice as great trading centres made them intellectual crossroads. Merchants brought with them ideas from far corners of the globe, particularly the Levant . Venice was Europe's gateway to trade with the East, and a producer of fine glass , while Florence was a capital of textiles. The wealth such business brought to Italy meant large public and private artistic projects could be commissioned and individuals had more leisure time for study. One theory that has been advanced
15738-405: Was formalized as an artistic technique. The development of perspective was part of a wider trend toward realism in the arts. Painters developed other techniques, studying light, shadow, and, famously in the case of Leonardo da Vinci , human anatomy . Underlying these changes in artistic method was a renewed desire to depict the beauty of nature and to unravel the axioms of aesthetics , with
15867-494: Was particularly influential on the development of painting in Italy, both technically with the introduction of oil paint and canvas, and stylistically in terms of naturalism in representation. Later, the work of Pieter Brueghel the Elder would inspire artists to depict themes of everyday life. In architecture, Filippo Brunelleschi was foremost in studying the remains of ancient classical buildings. With rediscovered knowledge from
15996-607: Was recorded in Babylonian tablets which state that the comet was seen "day beyond day" for a month. This appearance may be recalled in the representation of Tigranes the Great , an Armenian king who is depicted on coins with a crown that features, according to Vahe Gurzadyan and R. Vardanyan, "a star with a curved tail [that] may represent the passage of Halley's Comet in 87 BC." Gurzadyan and Vardanyan argue that "Tigranes could have seen Halley's Comet when it passed closest to
16125-515: Was said to herald the defeat of Attila the Hun at the Battle of Chalons . The 684 AD apparition was reported in Chinese records as the "broom star". The 760 AD apparition was recorded in the Zuqnin Chronicle ' s entry for iyyōr 1071 SE (May 760 AD ), calling it a "white sign": The year [SE] one thousand seventy one (AD 759/760). In the month of iyyōr (May) a white sign
16254-603: Was seen in the sky, before early twilight, in the north-east [quarter], in the Zodiac [sign] which is called Aries, to the north from these three stars in it, which are very shining. And it resembled in its shape a broom [...] And the sign itself remained for fifteen nights, until dawn of the feast of Pentecost . In 837 AD, Halley's Comet may have passed as close as 0.03 astronomical units (2.8 million miles; 4.5 million kilometres) from Earth , by far its closest approach. Its tail may have stretched 60 degrees across
16383-509: Was the first time anything other than planets had been shown to orbit the Sun. It was also one of the earliest successful tests of Newtonian physics , and a clear demonstration of its explanatory power. The comet was first named in Halley's honour by French astronomer Nicolas-Louis de Lacaille in 1759. Some scholars have proposed that first-century Mesopotamian astronomers already had recognised Halley's Comet as periodic. This theory notes
16512-418: Was the rebuilding of St. Peter's Basilica , combining the skills of Bramante , Michelangelo, Raphael, Sangallo and Maderno . During the Renaissance, architects aimed to use columns, pilasters , and entablatures as an integrated system. The Roman orders types of columns are used: Tuscan and Composite . These can either be structural, supporting an arcade or architrave, or purely decorative, set against
16641-427: Was thought that the classics provided moral instruction and an intensive understanding of human behavior. A unique characteristic of some Renaissance libraries is that they were open to the public. These libraries were places where ideas were exchanged and where scholarship and reading were considered both pleasurable and beneficial to the mind and soul. As freethinking was a hallmark of the age, many libraries contained
#61938