The armillary sphere, a three-dimensional representation of the movements in the celestial sphere, was invented in Han China by the 1st century BC. Using a water clock, waterwheel and a series of gears, the Court Astronomer Zhang Heng (78–139 AD) was able to mechanically rotate his metal-ringed armillary sphere. To address the problem of slowed timekeeping in the pressure head of the inflow water clock, Zhang was the first in China to install an additional tank between the reservoir and inflow vessel. Zhang also invented a seismometer (Houfeng didong yi 候风地动仪) in 132 AD to detect the exact cardinal or ordinal direction of earthquakes from hundreds of kilometers away. This employed an inverted pendulum that, when disturbed by ground tremors, would trigger a set of gears that dropped a metal ball from one of eight dragon mouths (representing all eight directions) into a metal toad's mouth.


Three Han mathematical treatises still exist. These are the Book on Numbers and Computation, the Arithmetical Classic of the Gnomon and the Circular Paths of Heaven and the Nine Chapters on the Mathematical Art. Han-era mathematical achievements include solving problems with right-angle triangles, square roots, cube roots, and matrix methods, finding more accurate approximations for pi, providing mathematical proof of the Pythagorean theorem, use of the decimal fraction, Gaussian elimination to solve linear equations, and continued fractions to find the roots of equations.


One of the Han's greatest mathematical advancements was the world's first use of negative numbers. Negative numbers first appeared in the Nine Chapters on the Mathematical Art as black counting rods, where positive numbers were represented by red counting rods. Negative numbers are used in the Bakhshali manuscript of ancient India, but its exact date of compilation is unknown. Negative numbers were also used by the Greek mathematician Diophantus in about 275 AD, but were not widely accepted in Europe until the 16th century AD.


Han-era astronomers adopted a geocentric model of the universe, theorizing that it was shaped like a sphere surrounding the earth in the center. They assumed that the Sun, Moon, and planets were spherical and not disc-shaped. They also thought that the illumination of the Moon and planets was caused by sunlight, that lunar eclipses occurred when the Earth obstructed sunlight falling onto the Moon, and that a solar eclipse occurred when the Moon obstructed sunlight from reaching the Earth. Although others disagreed with his model, Wang Chong accurately described the water cycle of the evaporation of water into clouds.


Evidence found in Chinese literature, and archaeological evidence, show that cartography existed in China before the Han. Some of the earliest Han maps discovered were ink-penned silk maps found amongst the Mawangdui Silk Texts in a 2nd-century-BC tomb. The general Ma Yuan created the world's first known raised-relief map from rice in the 1st century AD. This date could be revised if the tomb of Qin Shi Huang is excavated and the account in the Records of the Grand Historian concerning a model map of the empire is proven to be true.


The Han-era Chinese sailed in a variety of ships differing from those of previous eras, such as the tower ship. The junk design was developed and realized during Han. Junks featured a square-ended bow and stern, a flat-bottomed hull or carvel-shaped hull with no keel or sternpost, and solid transverse bulkheads in the place of structural ribs found in Western vessels. Moreover, Han ships were the first in the world to be steered using a rudder at the stern, in contrast to the simpler steering oar used for riverine transport, allowing them to sail on the high seas.


Han-era medical physicians believed that the human body was subject to the same forces of nature that governed the greater universe, namely the cosmological cycles of yin and yang and the five phases. Each organ of the body was associated with a particular phase. Illness was viewed as a sign that qi or "vital energy" channels leading to a certain organ had been disrupted. Thus, Han-era physicians prescribed medicine that was believed to counteract this imbalance. For example, since the wood phase was believed to promote the fire phase, medicinal ingredients associated with the wood phase could be used to heal an organ associated with the fire phase. To this end, the physician Zhang Zhongjing (c. 150–c. 219 AD) prescribed regulated diets rich in certain foods that were thought to cure specific illnesses. These are now known to be nutrition disorders caused by the lack of certain vitamins consumed in one's diet. Besides dieting, Han physicians also prescribed moxibustion, acupuncture, and calisthenics as methods of maintaining one's health. When surgery was performed by the physician Hua Tuo (d. 208 AD), he used anesthesia to numb his patients' pain and prescribed a rubbing ointment that allegedly sped the process of healing surgical wounds.


Muslims believe the Quran was verbally revealed by God to Muhammad through the angel Gabriel (Jibril), gradually over a period of approximately 23 years, beginning on 22 December 609 CE, when Muhammad was 40, and concluding in 632, the year of his death. Muslims regard the Quran as the most important miracle of Muhammad, a proof of his prophethood, and the culmination of a series of divine messages that started with the messages revealed to Adam and ended with Muhammad. The word "Quran" occurs some 70 times in the text of the Quran, although different names and words are also said to be references to the Quran.


According to the traditional narrative, several companions of Muhammad served as scribes and were responsible for writing down the revelations. Shortly after Muhammad's death, the Quran was compiled by his companions who wrote down and memorized parts of it. These codices had differences that motivated the Caliph Uthman to establish a standard version now known as Uthman's codex, which is generally considered the archetype of the Quran known today. There are, however, variant readings, with mostly minor differences in meaning.


The Quran assumes familiarity with major narratives recounted in the Biblical scriptures. It summarizes some, dwells at length on others and, in some cases, presents alternative accounts and interpretations of events. The Quran describes itself as a book of guidance. It sometimes offers detailed accounts of specific historical events, and it often emphasizes the moral significance of an event over its narrative sequence. The Quran is used along with the hadith to interpret sharia law. During prayers, the Quran is recited only in Arabic.


The word qurʼān appears about 70 times in the Quran itself, assuming various meanings. It is a verbal noun (maṣdar) of the Arabic verb qaraʼa (قرأ), meaning "he read" or "he recited". The Syriac equivalent is (ܩܪܝܢܐ) qeryānā, which refers to "scripture reading" or "lesson". While some Western scholars consider the word to be derived from the Syriac, the majority of Muslim authorities hold the origin of the word is qaraʼa itself. Regardless, it had become an Arabic term by Muhammad's lifetime. An important meaning of the word is the "act of reciting", as reflected in an early Quranic passage: "It is for Us to collect it and to recite it (qurʼānahu)."


The term also has closely related synonyms that are employed throughout the Quran. Each synonym possesses its own distinct meaning, but its use may converge with that of qurʼān in certain contexts. Such terms include kitāb (book); āyah (sign); and sūrah (scripture). The latter two terms also denote units of revelation. In the large majority of contexts, usually with a definite article (al-), the word is referred to as the "revelation" (waḥy), that which has been "sent down" (tanzīl) at intervals. Other related words are: dhikr (remembrance), used to refer to the Quran in the sense of a reminder and warning, and ḥikmah (wisdom), sometimes referring to the revelation or part of it.


The Quran describes itself as "the discernment" (al-furqān), "the mother book" (umm al-kitāb), "the guide" (huda), "the wisdom" (hikmah), "the remembrance" (dhikr) and "the revelation" (tanzīl; something sent down, signifying the descent of an object from a higher place to lower place). Another term is al-kitāb (The Book), though it is also used in the Arabic language for other scriptures, such as the Torah and the Gospels. The adjective of "Quran" has multiple transliterations including "quranic", "koranic", and "qur'anic", or capitalised as "Qur'anic", "Koranic", and "Quranic". The term mus'haf ('written work') is often used to refer to particular Quranic manuscripts but is also used in the Quran to identify earlier revealed books. Other transliterations of "Quran" include "al-Coran", "Coran", "Kuran", and "al-Qurʼan".


Islamic tradition relates that Muhammad received his first revelation in the Cave of Hira during one of his isolated retreats to the mountains. Thereafter, he received revelations over a period of 23 years. According to hadith and Muslim history, after Muhammad immigrated to Medina and formed an independent Muslim community, he ordered many of his companions to recite the Quran and to learn and teach the laws, which were revealed daily. It is related that some of the Quraysh who were taken prisoners at the battle of Badr regained their freedom after they had taught some of the Muslims the simple writing of the time. Thus a group of Muslims gradually became literate. As it was initially spoken, the Quran was recorded on tablets, bones, and the wide, flat ends of date palm fronds. Most suras were in use amongst early Muslims since they are mentioned in numerous sayings by both Sunni and Shia sources, relating Muhammad's use of the Quran as a call to Islam, the making of prayer and the manner of recitation. However, the Quran did not exist in book form at the time of Muhammad's death in 632. There is agreement among scholars that Muhammad himself did not write down the revelation.


The Quran describes Muhammad as "ummi", which is traditionally interpreted as "illiterate," but the meaning is rather more complex. Medieval commentators such as Al-Tabari maintained that the term induced two meanings: first, the inability to read or write in general; second, the inexperience or ignorance of the previous books or scriptures (but they gave priority to the first meaning). Muhammad's illiteracy was taken as a sign of the genuineness of his prophethood. For example, according to Fakhr al-Din al-Razi, if Muhammad had mastered writing and reading he possibly would have been suspected of having studied the books of the ancestors. Some scholars such as Watt prefer the second meaning of "ummi" - they take it to indicate unfamiliarity with earlier sacred texts.


Based on earlier transmitted reports, in the year 632, after the demise of Muhammad a number of his companions who knew the Quran by heart were killed in a battle by Musaylimah, the first caliph Abu Bakr (d. 634) decided to collect the book in one volume so that it could be preserved. Zayd ibn Thabit (d. 655) was the person to collect the Quran since "he used to write the Divine Inspiration for Allah's Apostle". Thus, a group of scribes, most importantly Zayd, collected the verses and produced a hand-written manuscript of the complete book. The manuscript according to Zayd remained with Abu Bakr until he died. Zayd's reaction to the task and the difficulties in collecting the Quranic material from parchments, palm-leaf stalks, thin stones and from men who knew it by heart is recorded in earlier narratives. After Abu Bakr, Hafsa bint Umar, Muhammad's widow, was entrusted with the manuscript. In about 650, the third Caliph Uthman ibn Affan (d. 656) began noticing slight differences in pronunciation of the Quran as Islam expanded beyond the Arabian Peninsula into Persia, the Levant, and North Africa. In order to preserve the sanctity of the text, he ordered a committee headed by Zayd to use Abu Bakr's copy and prepare a standard copy of the Quran. Thus, within 20 years of Muhammad's death, the Quran was committed to written form. That text became the model from which copies were made and promulgated throughout the urban centers of the Muslim world, and other versions are believed to have been destroyed. The present form of the Quran text is accepted by Muslim scholars to be the original version compiled by Abu Bakr.


In 1972, in a mosque in the city of Sana'a, Yemen, manuscripts were discovered that were later proved to be the most ancient Quranic text known to exist at the time. The Sana'a manuscripts contain palimpsests, a manuscript page from which the text has been washed off to make the parchment reusable again—a practice which was common in ancient times due to scarcity of writing material. However, the faint washed-off underlying text (scriptio inferior) is still barely visible and believed to be "pre-Uthmanic" Quranic content, while the text written on top (scriptio superior) is believed to belong to Uthmanic time. Studies using radiocarbon dating indicate that the parchments are dated to the period before 671 AD with a 99 percent probability.


In 2015, fragments of a very early Quran, dating back to 1370 years ago, were discovered in the library of the University of Birmingham, England. According to the tests carried out by Oxford University Radiocarbon Accelerator Unit, "with a probability of more than 95%, the parchment was from between 568 and 645". The manuscript is written in Hijazi script, an early form of written Arabic. This is possibly the earliest extant exemplar of the Quran, but as the tests allow a range of possible dates, it cannot be said with certainty which of the existing versions is the oldest. Saudi scholar Saud al-Sarhan has expressed doubt over the age of the fragments as they contain dots and chapter separators that are believed to have originated later.


Respect for the written text of the Quran is an important element of religious faith by many Muslims, and the Quran is treated with reverence. Based on tradition and a literal interpretation of Quran 56:79 ("none shall touch but those who are clean"), some Muslims believe that they must perform a ritual cleansing with water before touching a copy of the Quran, although this view is not universal. Worn-out copies of the Quran are wrapped in a cloth and stored indefinitely in a safe place, buried in a mosque or a Muslim cemetery, or burned and the ashes buried or scattered over water.


Inimitability of the Quran (or "I'jaz") is the belief that no human speech can match the Quran in its content and form. The Quran is considered an inimitable miracle by Muslims, effective until the Day of Resurrection—and, thereby, the central proof granted to Muhammad in authentication of his prophetic status. The concept of inimitability originates in the Quran where in five different verses opponents are challenged to produce something like the Quran: "If men and sprites banded together to produce the like of this Quran they would never produce its like not though they backed one another." So the suggestion is that if there are doubts concerning the divine authorship of the Quran, come forward and create something like it. From the ninth century, numerous works appeared which studied the Quran and examined its style and content. Medieval Muslim scholars including al-Jurjani (d. 1078) and al-Baqillani (d. 1013) have written treatises on the subject, discussed its various aspects, and used linguistic approaches to study the Quran. Others argue that the Quran contains noble ideas, has inner meanings, maintained its freshness through the ages and has caused great transformations in individual level and in the history. Some scholars state that the Quran contains scientific information that agrees with modern science. The doctrine of miraculousness of the Quran is further emphasized by Muhammad's illiteracy since the unlettered prophet could not have been suspected of composing the Quran.


The Quran consists of 114 chapters of varying lengths, each known as a sura. Suras are classified as Meccan or Medinan, depending on whether the verses were revealed before or after the migration of Muhammad to the city of Medina. However, a sura classified as Medinan may contain Meccan verses in it and vice versa. Sura titles are derived from a name or quality discussed in the text, or from the first letters or words of the sura. Suras are arranged roughly in order of decreasing size. The sura arrangement is thus not connected to the sequence of revelation. Each sura except the ninth starts with the Bismillah (بسم الله الرحمن الرحيم), an Arabic phrase meaning "In the name of God". There are, however, still 114 occurrences of the Bismillah in the Quran, due to its presence in Quran 27:30 as the opening of Solomon's letter to the Queen of Sheba.


In addition to and independent of the division into suras, there are various ways of dividing the Quran into parts of approximately equal length for convenience in reading. The 30 juz' (plural ajzāʼ) can be used to read through the entire Quran in a month. Some of these parts are known by names—which are the first few words by which the juzʼ starts. A juz' is sometimes further divided into two ḥizb (plural aḥzāb), and each hizb subdivided into four rubʻ al-ahzab. The Quran is also divided into seven approximately equal parts, manzil (plural manāzil), for it to be recited in a week.


The Quranic content is concerned with basic Islamic beliefs including the existence of God and the resurrection. Narratives of the early prophets, ethical and legal subjects, historical events of Muhammad's time, charity and prayer also appear in the Quran. The Quranic verses contain general exhortations regarding right and wrong and historical events are related to outline general moral lessons. Verses pertaining to natural phenomena have been interpreted by Muslims as an indication of the authenticity of the Quranic message.


The doctrine of the last day and eschatology (the final fate of the universe) may be reckoned as the second great doctrine of the Quran. It is estimated that approximately one-third of the Quran is eschatological, dealing with the afterlife in the next world and with the day of judgment at the end of time. There is a reference to the afterlife on most pages of the Quran and belief in the afterlife is often referred to in conjunction with belief in God as in the common expression: "Believe in God and the last day". A number of suras such as 44, 56, 75, 78, 81 and 101 are directly related to the afterlife and its preparations. Some suras indicate the closeness of the event and warn people to be prepared for the imminent day. For instance, the first verses of Sura 22, which deal with the mighty earthquake and the situations of people on that day, represent this style of divine address: "O People! Be respectful to your Lord. The earthquake of the Hour is a mighty thing."


According to the Quran, God communicated with man and made his will known through signs and revelations. Prophets, or 'Messengers of God', received revelations and delivered them to humanity. The message has been identical and for all humankind. "Nothing is said to you that was not said to the messengers before you, that your lord has at his Command forgiveness as well as a most Grievous Penalty." The revelation does not come directly from God to the prophets. Angels acting as God's messengers deliver the divine revelation to them. This comes out in Quran 42:51, in which it is stated: "It is not for any mortal that God should speak to them, except by revelation, or from behind a veil, or by sending a messenger to reveal by his permission whatsoever He will."


Belief is a fundamental aspect of morality in the Quran, and scholars have tried to determine the semantic contents of "belief" and "believer" in the Quran. The ethico-legal concepts and exhortations dealing with righteous conduct are linked to a profound awareness of God, thereby emphasizing the importance of faith, accountability, and the belief in each human's ultimate encounter with God. People are invited to perform acts of charity, especially for the needy. Believers who "spend of their wealth by night and by day, in secret and in public" are promised that they "shall have their reward with their Lord; on them shall be no fear, nor shall they grieve". It also affirms family life by legislating on matters of marriage, divorce, and inheritance. A number of practices, such as usury and gambling, are prohibited. The Quran is one of the fundamental sources of Islamic law (sharia). Some formal religious practices receive significant attention in the Quran including the formal prayers (salat) and fasting in the month of Ramadan. As for the manner in which the prayer is to be conducted, the Quran refers to prostration. The term for charity, zakat, literally means purification. Charity, according to the Quran, is a means of self-purification.


The astrophysicist Nidhal Guessoum while being highly critical of pseudo-scientific claims made about the Quran, has highlighted the encouragement for sciences that the Quran provides by developing "the concept of knowledge.". He writes: "The Qur'an draws attention to the danger of conjecturing without evidence (And follow not that of which you have not the (certain) knowledge of... 17:36) and in several different verses asks Muslims to require proofs (Say: Bring your proof if you are truthful 2:111), both in matters of theological belief and in natural science." Guessoum cites Ghaleb Hasan on the definition of "proof" according the Quran being "clear and strong... convincing evidence or argument." Also, such a proof cannot rely on an argument from authority, citing verse 5:104. Lastly, both assertions and rejections require a proof, according to verse 4:174. Ismail al-Faruqi and Taha Jabir Alalwani are of the view that any reawakening of the Muslim civilization must start with the Quran; however, the biggest obstacle on this route is the "centuries old heritage of tafseer (exegesis) and other classical disciplines" which inhibit a "universal, epidemiological and systematic conception" of the Quran's message. The philosopher Muhammad Iqbal, considered the Quran's methodology and epistemology to be empirical and rational.


It's generally accepted that there are around 750 verses in the Quran dealing with natural phenomenon. In many of these verses the study of nature is "encouraged and highly recommended," and historical Islamic scientists like Al-Biruni and Al-Battani derived their inspiration from verses of the Quran. Mohammad Hashim Kamali has the stated that "scientific observation, experimental knowledge and rationality" are the primary tools with which humanity can achieve the goals laid out for it in the Quran. Ziauddin Sardar built a case for Muslims having developed the foundations of modern science, by highlighting the repeated calls of the Quran to observe and reflect upon natural phenomenon. "The 'scientific method,' as it is understood today, was first developed by Muslim scientists" like Ibn al-Haytham and Al-Biruni, along with numerous other Muslim scientists.


The physicist Abdus Salam, in his Nobel Prize banquet address, quoted a well known verse from the Quran (67:3-4) and then stated: "This in effect is the faith of all physicists: the deeper we seek, the more is our wonder excited, the more is the dazzlement of our gaze". One of Salam's core beliefs was that there is no contradiction between Islam and the discoveries that science allows humanity to make about nature and the universe. Salam also held the opinion that the Quran and the Islamic spirit of study and rational reflection was the source of extraordinary civilizational development. Salam highlights, in particular, the work of Ibn al-Haytham and Al-Biruni as the pioneers of empiricism who introduced the experimental approach, breaking way from Aristotle's influence, and thus giving birth to modern science. Salam was also careful to differentiate between metaphysics and physics, and advised against empirically probing certain matters on which "physics is silent and will remain so," such as the doctrine of "creation from nothing" which in Salam's view is outside the limits of science and thus "gives way" to religious considerations.


The language of the Quran has been described as "rhymed prose" as it partakes of both poetry and prose; however, this description runs the risk of failing to convey the rhythmic quality of Quranic language, which is more poetic in some parts and more prose-like in others. Rhyme, while found throughout the Quran, is conspicuous in many of the earlier Meccan suras, in which relatively short verses throw the rhyming words into prominence. The effectiveness of such a form is evident for instance in Sura 81, and there can be no doubt that these passages impressed the conscience of the hearers. Frequently a change of rhyme from one set of verses to another signals a change in the subject of discussion. Later sections also preserve this form but the style is more expository.


The Quranic text seems to have no beginning, middle, or end, its nonlinear structure being akin to a web or net. The textual arrangement is sometimes considered to exhibit lack of continuity, absence of any chronological or thematic order and repetitiousness. Michael Sells, citing the work of the critic Norman O. Brown, acknowledges Brown's observation that the seeming disorganization of Quranic literary expression – its scattered or fragmented mode of composition in Sells's phrase – is in fact a literary device capable of delivering profound effects as if the intensity of the prophetic message were shattering the vehicle of human language in which it was being communicated. Sells also addresses the much-discussed repetitiveness of the Quran, seeing this, too, as a literary device.


A text is self-referential when it speaks about itself and makes reference to itself. According to Stefan Wild, the Quran demonstrates this metatextuality by explaining, classifying, interpreting and justifying the words to be transmitted. Self-referentiality is evident in those passages where the Quran refers to itself as revelation (tanzil), remembrance (dhikr), news (naba'), criterion (furqan) in a self-designating manner (explicitly asserting its Divinity, "And this is a blessed Remembrance that We have sent down; so are you now denying it?"), or in the frequent appearance of the "Say" tags, when Muhammad is commanded to speak (e.g., "Say: 'God's guidance is the true guidance' ", "Say: 'Would you then dispute with us concerning God?' "). According to Wild the Quran is highly self-referential. The feature is more evident in early Meccan suras.


Tafsir is one of the earliest academic activities of Muslims. According to the Quran, Muhammad was the first person who described the meanings of verses for early Muslims. Other early exegetes included a few Companions of Muhammad, like ʻAli ibn Abi Talib, ʻAbdullah ibn Abbas, ʻAbdullah ibn Umar and Ubayy ibn Kaʻb. Exegesis in those days was confined to the explanation of literary aspects of the verse, the background of its revelation and, occasionally, interpretation of one verse with the help of the other. If the verse was about a historical event, then sometimes a few traditions (hadith) of Muhammad were narrated to make its meaning clear.


Because the Quran is spoken in classical Arabic, many of the later converts to Islam (mostly non-Arabs) did not always understand the Quranic Arabic, they did not catch allusions that were clear to early Muslims fluent in Arabic and they were concerned with reconciling apparent conflict of themes in the Quran. Commentators erudite in Arabic explained the allusions, and perhaps most importantly, explained which Quranic verses had been revealed early in Muhammad's prophetic career, as being appropriate to the very earliest Muslim community, and which had been revealed later, canceling out or "abrogating" (nāsikh) the earlier text (mansūkh). Other scholars, however, maintain that no abrogation has taken place in the Quran. The Ahmadiyya Muslim Community has published a ten-volume Urdu commentary on the Quran, with the name Tafseer e Kabir.


Esoteric or Sufi interpretation attempts to unveil the inner meanings of the Quran. Sufism moves beyond the apparent (zahir) point of the verses and instead relates Quranic verses to the inner or esoteric (batin) and metaphysical dimensions of consciousness and existence. According to Sands, esoteric interpretations are more suggestive than declarative, they are allusions (isharat) rather than explanations (tafsir). They indicate possibilities as much as they demonstrate the insights of each writer.


Moses, in 7:143, comes the way of those who are in love, he asks for a vision but his desire is denied, he is made to suffer by being commanded to look at other than the Beloved while the mountain is able to see God. The mountain crumbles and Moses faints at the sight of God's manifestation upon the mountain. In Qushayri's words, Moses came like thousands of men who traveled great distances, and there was nothing left to Moses of Moses. In that state of annihilation from himself, Moses was granted the unveiling of the realities. From the Sufi point of view, God is the always the beloved and the wayfarer's longing and suffering lead to realization of the truths.


One of the notable authors of esoteric interpretation prior to the 12th century is Sulami (d. 1021) without whose work the majority of very early Sufi commentaries would not have been preserved. Sulami's major commentary is a book named haqaiq al-tafsir ("Truths of Exegesis") which is a compilation of commentaries of earlier Sufis. From the 11th century onwards several other works appear, including commentaries by Qushayri (d. 1074), Daylami (d. 1193), Shirazi (d. 1209) and Suhrawardi (d. 1234). These works include material from Sulami's books plus the author's contributions. Many works are written in Persian such as the works of Maybudi (d. 1135) kash al-asrar ("the unveiling of the secrets"). Rumi (d. 1273) wrote a vast amount of mystical poetry in his book Mathnawi. Rumi makes heavy use of the Quran in his poetry, a feature that is sometimes omitted in translations of Rumi's work. A large number of Quranic passages can be found in Mathnawi, which some consider a kind of Sufi interpretation of the Quran. Rumi's book is not exceptional for containing citations from and elaboration on the Quran, however, Rumi does mention Quran more frequently. Simnani (d. 1336) wrote two influential works of esoteric exegesis on the Quran. He reconciled notions of God's manifestation through and in the physical world with the sentiments of Sunni Islam. Comprehensive Sufi commentaries appear in the 18th century such as the work of Ismail Hakki Bursevi (d. 1725). His work ruh al-Bayan (the Spirit of Elucidation) is a voluminous exegesis. Written in Arabic, it combines the author's own ideas with those of his predecessors (notably Ibn Arabi and Ghazali), all woven together in Hafiz, a Persian poetry form.


Commentaries dealing with the zahir (outward aspects) of the text are called tafsir, and hermeneutic and esoteric commentaries dealing with the batin are called ta'wil ("interpretation" or "explanation"), which involves taking the text back to its beginning. Commentators with an esoteric slant believe that the ultimate meaning of the Quran is known only to God. In contrast, Quranic literalism, followed by Salafis and Zahiris, is the belief that the Quran should only be taken at its apparent meaning.[citation needed]


The first fully attested complete translations of the Quran were done between the 10th and 12th centuries in Persian. The Samanid king, Mansur I (961-976), ordered a group of scholars from Khorasan to translate the Tafsir al-Tabari, originally in Arabic, into Persian. Later in the 11th century, one of the students of Abu Mansur Abdullah al-Ansari wrote a complete tafsir of the Quran in Persian. In the 12th century, Najm al-Din Abu Hafs al-Nasafi translated the Quran into Persian. The manuscripts of all three books have survived and have been published several times.[citation needed]


Robert of Ketton's 1143 translation of the Quran for Peter the Venerable, Lex Mahumet pseudoprophete, was the first into a Western language (Latin). Alexander Ross offered the first English version in 1649, from the French translation of L'Alcoran de Mahomet (1647) by Andre du Ryer. In 1734, George Sale produced the first scholarly translation of the Quran into English; another was produced by Richard Bell in 1937, and yet another by Arthur John Arberry in 1955. All these translators were non-Muslims. There have been numerous translations by Muslims. The Ahmadiyya Muslim Community has published translations of the Quran in 50 different languages besides a five-volume English commentary and an English translation of the Quran.


The proper recitation of the Quran is the subject of a separate discipline named tajwid which determines in detail how the Quran should be recited, how each individual syllable is to be pronounced, the need to pay attention to the places where there should be a pause, to elisions, where the pronunciation should be long or short, where letters should be sounded together and where they should be kept separate, etc. It may be said that this discipline studies the laws and methods of the proper recitation of the Quran and covers three main areas: the proper pronunciation of consonants and vowels (the articulation of the Quranic phonemes), the rules of pause in recitation and of resumption of recitation, and the musical and melodious features of recitation.


Vocalization markers indicating specific vowel sounds were introduced into the Arabic language by the end of the 9th century. The first Quranic manuscripts lacked these marks, therefore several recitations remain acceptable. The variation in readings of the text permitted by the nature of the defective vocalization led to an increase in the number of readings during the 10th century. The 10th-century Muslim scholar from Baghdad, Ibn Mujāhid, is famous for establishing seven acceptable textual readings of the Quran. He studied various readings and their trustworthiness and chose seven 8th-century readers from the cities of Mecca, Medina, Kufa, Basra and Damascus. Ibn Mujahid did not explain why he chose seven readers, rather than six or ten, but this may be related to a prophetic tradition (Muhammad's saying) reporting that the Quran had been revealed in seven "ahruf" (meaning seven letters or modes). Today, the most popular readings are those transmitted by Ḥafṣ (d.796) and Warsh (d. 812) which are according to two of Ibn Mujahid's reciters, Aasim ibn Abi al-Najud (Kufa, d. 745) and Nafi‘ al-Madani (Medina, d. 785), respectively. The influential standard Quran of Cairo (1924) uses an elaborate system of modified vowel-signs and a set of additional symbols for minute details and is based on ʻAsim's recitation, the 8th-century recitation of Kufa. This edition has become the standard for modern printings of the Quran.


Before printing was widely adopted in the 19th century, the Quran was transmitted in manuscripts made by calligraphers and copyists. The earliest manuscripts were written in Ḥijāzī-type script. The Hijazi style manuscripts nevertheless confirm that transmission of the Quran in writing began at an early stage. Probably in the ninth century, scripts began to feature thicker strokes, which are traditionally known as Kufic scripts. Toward the end of the ninth century, new scripts began to appear in copies of the Quran and replace earlier scripts. The reason for discontinuation in the use of the earlier style was that it took too long to produce and the demand for copies was increasing. Copyists would therefore chose simpler writing styles. Beginning in the 11th century, the styles of writing employed were primarily the naskh, muhaqqaq, rayḥānī and, on rarer occasions, the thuluth script. Naskh was in very widespread use. In North Africa and Spain, the Maghribī style was popular. More distinct is the Bihari script which was used solely in the north of India. Nastaʻlīq style was also rarely used in Persian world.


In the beginning, the Quran did not have vocalization markings. The system of vocalization, as we know it today, seems to have been introduced towards the end of the ninth century. Since it would have been too costly for most Muslims to purchase a manuscript, copies of the Quran were held in mosques in order to make them accessible to people. These copies frequently took the form of a series of 30 parts or juzʼ. In terms of productivity, the Ottoman copyists provide the best example. This was in response to widespread demand, unpopularity of printing methods and for aesthetic reasons.


According to Sahih al-Bukhari, the Quran was recited among Levantines and Iraqis, and discussed by Christians and Jews, before it was standardized. Its language was similar to the Syriac language.[citation needed] The Quran recounts stories of many of the people and events recounted in Jewish and Christian sacred books (Tanakh, Bible) and devotional literature (Apocrypha, Midrash), although it differs in many details. Adam, Enoch, Noah, Eber, Shelah, Abraham, Lot, Ishmael, Isaac, Jacob, Joseph, Job, Jethro, David, Solomon, Elijah, Elisha, Jonah, Aaron, Moses, Zechariah, John the Baptist and Jesus are mentioned in the Quran as prophets of God (see Prophets of Islam). In fact, Moses is mentioned more in the Quran than any other individual. Jesus is mentioned more often in the Quran than Muhammad, while Mary is mentioned in the Quran more than the New Testament. Muslims believe the common elements or resemblances between the Bible and other Jewish and Christian writings and Islamic dispensations is due to their common divine source,[citation needed] and that the original Christian or Jewish texts were authentic divine revelations given to prophets.


According to Tabatabaei, there are acceptable and unacceptable esoteric interpretations. Acceptable ta'wil refers to the meaning of a verse beyond its literal meaning; rather the implicit meaning, which ultimately is known only to God and can't be comprehended directly through human thought alone. The verses in question here refer to the human qualities of coming, going, sitting, satisfaction, anger and sorrow, which are apparently attributed to God. Unacceptable ta'wil is where one "transfers" the apparent meaning of a verse to a different meaning by means of a proof; this method is not without obvious inconsistencies. Although this unacceptable ta'wil has gained considerable acceptance, it is incorrect and cannot be applied to the Quranic verses. The correct interpretation is that reality a verse refers to. It is found in all verses, the decisive and the ambiguous alike; it is not a sort of a meaning of the word; it is a fact that is too sublime for words. God has dressed them with words to bring them a bit nearer to our minds; in this respect they are like proverbs that are used to create a picture in the mind, and thus help the hearer to clearly grasp the intended idea.


The Quran most likely existed in scattered written form during Muhammad's lifetime. Several sources indicate that during Muhammad's lifetime a large number of his companions had memorized the revelations. Early commentaries and Islamic historical sources support the above-mentioned understanding of the Quran's early development. The Quran in its present form is generally considered by academic scholars to record the words spoken by Muhammad because the search for variants has not yielded any differences of great significance.[page needed] University of Chicago professor Fred Donner states that "...there was a very early attempt to establish a uniform consonantal text of the Qurʾān from what was probably a wider and more varied group of related texts in early transmission. [...] After the creation of this standardized canonical text, earlier authoritative texts were suppressed, and all extant manuscripts—despite their numerous variants—seem to date to a time after this standard consonantal text was established." Although most variant readings of the text of the Quran have ceased to be transmitted, some still are. There has been no critical text produced on which a scholarly reconstruction of the Quranic text could be based. Historically, controversy over the Quran's content has rarely become an issue, although debates continue on the subject.


Sahih al-Bukhari narrates Muhammad describing the revelations as, "Sometimes it is (revealed) like the ringing of a bell" and Aisha reported, "I saw the Prophet being inspired Divinely on a very cold day and noticed the sweat dropping from his forehead (as the Inspiration was over)." Muhammad's first revelation, according to the Quran, was accompanied with a vision. The agent of revelation is mentioned as the "one mighty in power", the one who "grew clear to view when he was on the uppermost horizon. Then he drew nigh and came down till he was (distant) two bows' length or even nearer." The Islamic studies scholar Welch states in the Encyclopaedia of Islam that he believes the graphic descriptions of Muhammad's condition at these moments may be regarded as genuine, because he was severely disturbed after these revelations. According to Welch, these seizures would have been seen by those around him as convincing evidence for the superhuman origin of Muhammad's inspirations. However, Muhammad's critics accused him of being a possessed man, a soothsayer or a magician since his experiences were similar to those claimed by such figures well known in ancient Arabia. Welch additionally states that it remains uncertain whether these experiences occurred before or after Muhammad's initial claim of prophethood.


Muhammad Husayn Tabatabaei says that according to the popular explanation among the later exegetes, ta'wil indicates the particular meaning a verse is directed towards. The meaning of revelation (tanzil), as opposed to ta'wil, is clear in its accordance to the obvious meaning of the words as they were revealed. But this explanation has become so widespread that, at present, it has become the primary meaning of ta'wil, which originally meant "to return" or "the returning place". In Tabatabaei's view, what has been rightly called ta'wil, or hermeneutic interpretation of the Quran, is not concerned simply with the denotation of words. Rather, it is concerned with certain truths and realities that transcend the comprehension of the common run of men; yet it is from these truths and realities that the principles of doctrine and the practical injunctions of the Quran issue forth. Interpretation is not the meaning of the verse—rather it transpires through that meaning, in a special sort of transpiration. There is a spiritual reality—which is the main objective of ordaining a law, or the basic aim in describing a divine attribute—and then there is an actual significance that a Quranic story refers to.


According to Shia beliefs, those who are firmly rooted in knowledge like Muhammad and the imams know the secrets of the Quran. According to Tabatabaei, the statement "none knows its interpretation except God" remains valid, without any opposing or qualifying clause. Therefore, so far as this verse is concerned, the knowledge of the Quran's interpretation is reserved for God. But Tabatabaei uses other verses and concludes that those who are purified by God know the interpretation of the Quran to a certain extent.


From 1989 through 1996, the total area of the US was listed as 9,372,610 km2 (3,618,780 sq mi) (land + inland water only). The listed total area changed to 9,629,091 km2 (3,717,813 sq mi) in 1997 (Great Lakes area and coastal waters added), to 9,631,418 km2 (3,718,711 sq mi) in 2004, to 9,631,420 km2 (3,718,710 sq mi) in 2006, and to 9,826,630 km2 (3,794,080 sq mi) in 2007 (territorial waters added). Currently, the CIA World Factbook gives 9,826,675 km2 (3,794,100 sq mi), the United Nations Statistics Division gives 9,629,091 km2 (3,717,813 sq mi), and the Encyclopædia Britannica gives 9,522,055 km2 (3,676,486 sq mi)(Great Lakes area included but not coastal waters). These source consider only the 50 states and the Federal District, and exclude overseas territories.


By total area (water as well as land), the United States is either slightly larger or smaller than the People's Republic of China, making it the world's third or fourth largest country. China and the United States are smaller than Russia and Canada in total area, but are larger than Brazil. By land area only (exclusive of waters), the United States is the world's third largest country, after Russia and China, with Canada in fourth. Whether the US or China is the third largest country by total area depends on two factors: (1) The validity of China's claim on Aksai Chin and Trans-Karakoram Tract. Both these territories are also claimed by India, so are not counted; and (2) How US calculates its own surface area. Since the initial publishing of the World Factbook, the CIA has updated the total area of United States a number of times.


The United States shares land borders with Canada (to the north) and Mexico (to the south), and a territorial water border with Russia in the northwest, and two territorial water borders in the southeast between Florida and Cuba, and Florida and the Bahamas. The contiguous forty-eight states are otherwise bounded by the Pacific Ocean on the west, the Atlantic Ocean on the east, and the Gulf of Mexico to the southeast. Alaska borders the Pacific Ocean to the south, the Bering Strait to the west, and the Arctic Ocean to the north, while Hawaii lies far to the southwest of the mainland in the Pacific Ocean.


The capital city, Washington, District of Columbia, is a federal district located on land donated by the state of Maryland. (Virginia had also donated land, but it was returned in 1849.) The United States also has overseas territories with varying levels of independence and organization: in the Caribbean the territories of Puerto Rico and the U.S. Virgin Islands, and in the Pacific the inhabited territories of Guam, American Samoa, and the Northern Mariana Islands, along with a number of uninhabited island territories.


The five Great Lakes are located in the north-central portion of the country, four of them forming part of the border with Canada, only Lake Michigan situated entirely within United States. The southeast United States contain subtropical forests and, near the gulf coast, mangrove wetlands, especially in Florida. West of the Appalachians lies the Mississippi River basin and two large eastern tributaries, the Ohio River and the Tennessee River. The Ohio and Tennessee Valleys and the Midwest consist largely of rolling hills and productive farmland, stretching south to the Gulf Coast.


The Great Plains lie west of the Mississippi River and east of the Rocky Mountains. A large portion of the country's agricultural products are grown in the Great Plains. Before their general conversion to farmland, the Great Plains were noted for their extensive grasslands, from tallgrass prairie in the eastern plains to shortgrass steppe in the western High Plains. Elevation rises gradually from less than a few hundred feet near the Mississippi River to more than a mile high in the High Plains. The generally low relief of the plains is broken in several places, most notably in the Ozark and Ouachita Mountains, which form the U.S. Interior Highlands, the only major mountainous region between the Rocky Mountains and the Appalachian Mountains.


The Great Plains come to an abrupt end at the Rocky Mountains. The Rocky Mountains form a large portion of the Western U.S., entering from Canada and stretching nearly to Mexico. The Rocky Mountain region is the highest region of the United States by average elevation. The Rocky Mountains generally contain fairly mild slopes and wider peaks compared to some of the other great mountain ranges, with a few exceptions (such as the Teton Mountains in Wyoming and the Sawatch Range in Colorado). The highest peaks of the Rockies are found in Colorado, the tallest peak being Mount Elbert at 14,440 ft (4,400 m). The Rocky Mountains contain some of the most spectacular, and well known scenery in the world. In addition, instead of being one generally continuous and solid mountain range, it is broken up into a number of smaller, intermittent mountain ranges, forming a large series of basins and valleys.


West of the Rocky Mountains lies the Intermontane Plateaus (also known as the Intermountain West), a large, arid desert lying between the Rockies and the Cascades and Sierra Nevada ranges. The large southern portion, known as the Great Basin, consists of salt flats, drainage basins, and many small north-south mountain ranges. The Southwest is predominantly a low-lying desert region. A portion known as the Colorado Plateau, centered around the Four Corners region, is considered to have some of the most spectacular scenery in the world. It is accentuated in such national parks as Grand Canyon, Arches, Mesa Verde National Park and Bryce Canyon, among others. Other smaller Intermontane areas include the Columbia Plateau covering eastern Washington, western Idaho and northeast Oregon and the Snake River Plain in Southern Idaho.


The Intermontane Plateaus come to an end at the Cascade Range and the Sierra Nevada. The Cascades consist of largely intermittent, volcanic mountains, many rising prominently from the surrounding landscape. The Sierra Nevada, further south, is a high, rugged, and dense mountain range. It contains the highest point in the contiguous 48 states, Mount Whitney (14,505 ft or 4,421 m) It is located at the boundary between California's Inyo and Tulare counties, just 84.6 mi or 136.2 km west-northwest of the lowest point in North America at the Badwater Basin in Death Valley National Park at 279 ft or 85 m below sea level.


These areas contain some spectacular scenery as well, as evidenced by such national parks as Yosemite and Mount Rainier. West of the Cascades and Sierra Nevada is a series of valleys, such as the Central Valley in California and the Willamette Valley in Oregon. Along the coast is a series of low mountain ranges known as the Pacific Coast Ranges. Much of the Pacific Northwest coast is inhabited by some of the densest vegetation outside of the Tropics, and also the tallest trees in the world (the Redwoods).


The Atlantic coast of the United States is low, with minor exceptions. The Appalachian Highland owes its oblique northeast-southwest trend to crustal deformations which in very early geological time gave a beginning to what later came to be the Appalachian mountain system. This system had its climax of deformation so long ago (probably in Permian time) that it has since then been very generally reduced to moderate or low relief. It owes its present-day altitude either to renewed elevations along the earlier lines or to the survival of the most resistant rocks as residual mountains. The oblique trend of this coast would be even more pronounced but for a comparatively modern crustal movement, causing a depression in the northeast resulting in an encroachment of the sea upon the land. Additionally, the southeastern section has undergone an elevation resulting in the advance of the land upon the sea.


The east coast Appalachian system, originally forest covered, is relatively low and narrow and is bordered on the southeast and south by an important coastal plain. The Cordilleran system on the western side of the continent is lofty, broad and complicated having two branches, the Rocky Mountain System and the Pacific Mountain System. In between these mountain systems lie the Intermontaine Plateaus. Both the Columbia River and Colorado River rise far inland near the easternmost members of the Cordilleran system, and flow through plateaus and intermontaine basins to the ocean. Heavy forests cover the northwest coast, but elsewhere trees are found only on the higher ranges below the Alpine region. The intermontane valleys, plateaus and basins range from treeless to desert with the most arid region being in the southwest.


The Laurentian Highlands, the Interior Plains and the Interior Highlands lie between the two coasts, stretching from the Gulf of Mexico northward, far beyond the national boundary, to the Arctic Ocean. The central plains are divided by a hardly perceptible height of land into a Canadian and a United States portion. It is from the United States side, that the great Mississippi system discharges southward to the Gulf of Mexico. The upper Mississippi and some of the Ohio basin is the semi-arid prairie region, with trees originally only along the watercourses. The uplands towards the Appalachians were included in the great eastern forested area, while the western part of the plains has so dry a climate that its native plant life is scanty, and in the south it is practically barren.


Due to its large size and wide range of geographic features, the United States contains examples of nearly every global climate. The climate is temperate in most areas, subtropical in the Southern United States, tropical in Hawaii and southern Florida, polar in Alaska, semiarid in the Great Plains west of the 100th meridian, Mediterranean in coastal California and arid in the Great Basin. Its comparatively favorable agricultural climate contributed (in part) to the country's rise as a world power, with infrequent severe drought in the major agricultural regions, a general lack of widespread flooding, and a mainly temperate climate that receives adequate precipitation.


The Great Basin and Columbia Plateau (the Intermontane Plateaus) are arid or semiarid regions that lie in the rain shadow of the Cascades and Sierra Nevada. Precipitation averages less than 15 inches (38 cm). The Southwest is a hot desert, with temperatures exceeding 100 °F (37.8 °C) for several weeks at a time in summer. The Southwest and the Great Basin are also affected by the monsoon from the Gulf of California from July to September, which brings localized but often severe thunderstorms to the region.


Much of California consists of a Mediterranean climate, with sometimes excessive rainfall from October–April and nearly no rain the rest of the year. In the Pacific Northwest rain falls year-round, but is much heavier during winter and spring. The mountains of the west receive abundant precipitation and very heavy snowfall. The Cascades are one of the snowiest places in the world, with some places averaging over 600 inches (1,524 cm) of snow annually, but the lower elevations closer to the coast receive very little snow.


On average, the mountains of the western states receive the highest levels of snowfall on Earth. The greatest annual snowfall level is at Mount Rainier in Washington, at 692 inches (1,758 cm); the record there was 1,122 inches (2,850 cm) in the winter of 1971–72. This record was broken by the Mt. Baker Ski Area in northwestern Washington which reported 1,140 inches (2,896 cm) of snowfall for the 1998-99 snowfall season. Other places with significant snowfall outside the Cascade Range are the Wasatch Mountains, near the Great Salt Lake, the San Juan Mountains in Colorado, and the Sierra Nevada, near Lake Tahoe.


In the east, while snowfall does not approach western levels, the region near the Great Lakes and the mountains of the Northeast receive the most. Along the northwestern Pacific coast, rainfall is greater than anywhere else in the continental U.S., with Quinault Rainforest in Washington having an average of 137 inches (348 cm). Hawaii receives even more, with 460 inches (1,168 cm) measured annually on Mount Waialeale, in Kauai. The Mojave Desert, in the southwest, is home to the driest locale in the U.S. Yuma, Arizona, has an average of 2.63 inches (6.7 cm) of precipitation each year.


In central portions of the U.S., tornadoes are more common than anywhere else on Earth and touch down most commonly in the spring and summer. Deadly and destructive hurricanes occur almost every year along the Atlantic seaboard and the Gulf of Mexico. The Appalachian region and the Midwest experience the worst floods, though virtually no area in the U.S. is immune to flooding. The Southwest has the worst droughts; one is thought to have lasted over 500 years and to have hurt Ancestral Pueblo peoples. The West is affected by large wildfires each year.


Occasional severe flooding is experienced. There was the Great Mississippi Flood of 1927, the Great Flood of 1993, and widespread flooding and mudslides caused by the 1982-1983 El Niño event in the western United States. Localized flooding can, however, occur anywhere, and mudslides from heavy rain can cause problems in any mountainous area, particularly the Southwest. Large stretches of desert shrub in the west can fuel the spread of wildfires. The narrow canyons of many mountain areas in the west and severe thunderstorm activity during the summer lead to sometimes devastating flash floods as well, while Nor'Easter snowstorms can bring activity to a halt throughout the Northeast (although heavy snowstorms can occur almost anywhere).


The West Coast of the continental United States and areas of Alaska (including the Aleutian Islands, the Alaskan Peninsula and southern Alaskan coast) make up part of the Pacific Ring of Fire, an area of heavy tectonic and volcanic activity that is the source of 90% of the world's earthquakes.[citation needed] The American Northwest sees the highest concentration of active volcanoes in the United States, in Washington, Oregon and northern California along the Cascade Mountains. There are several active volcanoes located in the islands of Hawaii, including Kilauea in ongoing eruption since 1983, but they do not typically adversely affect the inhabitants of the islands. There has not been a major life-threatening eruption on the Hawaiian islands since the 17th century. Volcanic eruptions can occasionally be devastating, such as in the 1980 eruption of Mount St. Helens in Washington.


Compact Disc (CD) is a digital optical disc data storage format. The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. Audio CDs and audio CD players have been commercially available since October 1982.


In 2004, worldwide sales of audio CDs, CD-ROMs and CD-Rs reached about 30 billion discs. By 2007, 200 billion CDs had been sold worldwide. CDs are increasingly being replaced by other forms of digital storage and distribution, with the result that audio CD sales rates in the U.S. have dropped about 50% from their peak; however, they remain one of the primary distribution methods for the music industry. In 2014, revenues from digital music services matched those from physical format sales for the first time.


The Compact Disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s. In 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980. After their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $1,000, over 400,000 CD players were sold in the United States between 1983 and 1984. The success of the compact disc has been credited to the cooperation between Philips and Sony, who came together to agree upon and develop compatible hardware. The unified design of the compact disc allowed consumers to purchase any disc or player from any company, and allowed the CD to dominate the at-home music market unchallenged.


In 1974, L. Ottens, director of the audio division of Philips, started a small group with the aim to develop an analog optical audio disc with a diameter of 20 cm and a sound quality superior to that of the vinyl record. However, due to the unsatisfactory performance of the analog format, two Philips research engineers recommended a digital format in March 1974. In 1977, Philips then established a laboratory with the mission of creating a digital audio disc. The diameter of Philips's prototype compact disc was set at 11.5 cm, the diagonal of an audio cassette.


Heitaro Nakajima, who developed an early digital audio recorder within Japan's national public broadcasting organization NHK in 1970, became general manager of Sony's audio department in 1971. His team developed a digital PCM adaptor audio tape recorder using a Betamax video recorder in 1973. After this, in 1974 the leap to storing digital audio on an optical disc was easily made. Sony first publicly demonstrated an optical digital audio disc in September 1976. A year later, in September 1977, Sony showed the press a 30 cm disc that could play 60 minutes of digital audio (44,100 Hz sampling rate and 16-bit resolution) using MFM modulation. In September 1978, the company demonstrated an optical digital audio disc with a 150-minute playing time, 44,056 Hz sampling rate, 16-bit linear resolution, and cross-interleaved error correction code—specifications similar to those later settled upon for the standard Compact Disc format in 1980. Technical details of Sony's digital audio disc were presented during the 62nd AES Convention, held on 13–16 March 1979, in Brussels. Sony's AES technical paper was published on 1 March 1979. A week later, on 8 March, Philips publicly demonstrated a prototype of an optical digital audio disc at a press conference called "Philips Introduce Compact Disc" in Eindhoven, Netherlands.


As a result, in 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. Led by engineers Kees Schouhamer Immink and Toshitada Doi, the research pushed forward laser and optical disc technology. After a year of experimentation and discussion, the task force produced the Red Book CD-DA standard. First published in 1980, the standard was formally adopted by the IEC as an international standard in 1987, with various amendments becoming part of the standard in 1996.


The Japanese launch was followed in March 1983 by the introduction of CD players and discs to Europe and North America (where CBS Records released sixteen titles). This event is often seen as the "Big Bang" of the digital audio revolution. The new audio disc was enthusiastically received, especially in the early-adopting classical music and audiophile communities, and its handling quality received particular praise. As the price of players gradually came down, and with the introduction of the portable Walkman the CD began to gain popularity in the larger popular and rock music markets. The first artist to sell a million copies on CD was Dire Straits, with their 1985 album Brothers in Arms. The first major artist to have his entire catalogue converted to CD was David Bowie, whose 15 studio albums were made available by RCA Records in February 1985, along with four greatest hits albums. In 1988, 400 million CDs were manufactured by 50 pressing plants around the world.


The CD was planned to be the successor of the gramophone record for playing music, rather than primarily as a data storage medium. From its origins as a musical format, CDs have grown to encompass other applications. In 1983, following the CD's introduction, Immink and Braat presented the first experiments with erasable compact discs during the 73rd AES Convention. In June 1985, the computer-readable CD-ROM (read-only memory) and, in 1990, CD-Recordable were introduced, also developed by both Sony and Philips. Recordable CDs were a new alternative to tape for recording music and copying music albums without defects introduced in compression used in other digital recording methods. Other newer video formats such as DVD and Blu-ray use the same physical geometry as CD, and most DVD and Blu-ray players are backward compatible with audio CD.


Meanwhile, with the advent and popularity of Internet-based distribution of files in lossily-compressed audio formats such as MP3, sales of CDs began to decline in the 2000s. For example, between 2000 - 2008, despite overall growth in music sales and one anomalous year of increase, major-label CD sales declined overall by 20%, although independent and DIY music sales may be tracking better according to figures released 30 March 2009, and CDs still continue to sell greatly. As of 2012, CDs and DVDs made up only 34 percent of music sales in the United States. In Japan, however, over 80 percent of music was bought on CDs and other physical formats as of 2015.


Replicated CDs are mass-produced initially using a hydraulic press. Small granules of heated raw polycarbonate plastic are fed into the press. A screw forces the liquefied plastic into the mold cavity. The mold closes with a metal stamper in contact with the disc surface. The plastic is allowed to cool and harden. Once opened, the disc substrate is removed from the mold by a robotic arm, and a 15 mm diameter center hole (called a stacking ring) is created. The time it takes to "stamp" one CD is usually two to three seconds.


This method produces the clear plastic blank part of the disc. After a metallic reflecting layer (usually aluminium, but sometimes gold or other metal) is applied to the clear blank substrate, the disc goes under a UV light for curing and it is ready to go to press. To prepare to press a CD, a glass master is made, using a high-powered laser on a device similar to a CD writer. The glass master is a positive image of the desired CD surface (with the desired microscopic pits and lands). After testing, it is used to make a die by pressing it against a metal disc.


The die is a negative image of the glass master: typically, several are made, depending on the number of pressing mills that are to make the CD. The die then goes into a press, and the physical image is transferred to the blank CD, leaving a final positive image on the disc. A small amount of lacquer is applied as a ring around the center of the disc, and rapid spinning spreads it evenly over the surface. Edge protection lacquer is applied before the disc is finished. The disc can then be printed and packed.


The most expensive part of a CD is the jewel case. In 1995, material costs were 30 cents for the jewel case and 10 to 15 cents for the CD. Wholesale cost of CDs was $0.75 to $1.15, which retailed for $16.98. On average, the store received 35 percent of the retail price, the record company 27 percent, the artist 16 percent, the manufacturer 13 percent, and the distributor 9 percent. When 8-track tapes, cassette tapes, and CDs were introduced, each was marketed at a higher price than the format they succeeded, even though the cost to produce the media was reduced. This was done because the apparent value increased. This continued from vinyl to CDs but was broken when Apple marketed MP3s for $0.99, and albums for $9.99. The incremental cost, though, to produce an MP3 is very small.


CD-R recordings are designed to be permanent. Over time, the dye's physical characteristics may change causing read errors and data loss until the reading device cannot recover with error correction methods. The design life is from 20 to 100 years, depending on the quality of the discs, the quality of the writing drive, and storage conditions. However, testing has demonstrated such degradation of some discs in as little as 18 months under normal storage conditions. This failure is known as disc rot, for which there are several, mostly environmental, reasons.


The ReWritable Audio CD is designed to be used in a consumer audio CD recorder, which will not (without modification) accept standard CD-RW discs. These consumer audio CD recorders use the Serial Copy Management System (SCMS), an early form of digital rights management (DRM), to conform to the United States' Audio Home Recording Act (AHRA). The ReWritable Audio CD is typically somewhat more expensive than CD-RW due to (a) lower volume and (b) a 3% AHRA royalty used to compensate the music industry for the making of a copy.


Due to technical limitations, the original ReWritable CD could be written no faster than 4x speed. High Speed ReWritable CD has a different design, which permits writing at speeds ranging from 4x to 12x. Original CD-RW drives can only write to original ReWritable CDs. High Speed CD-RW drives can typically write to both original ReWritable CDs and High Speed ReWritable CDs. Both types of CD-RW discs can be read in most CD drives. Higher speed CD-RW discs, Ultra Speed (16x to 24x write speed) and Ultra Speed+ (32x write speed) are now available.


A CD is read by focusing a 780 nm wavelength (near infrared) semiconductor laser housed within the CD player, through the bottom of the polycarbonate layer. The change in height between pits and lands results in a difference in the way the light is reflected. By measuring the intensity change with a photodiode, the data can be read from the disc. In order to accommodate the spiral pattern of data, the semiconductor laser is placed on a swing arm within the disc tray of any CD player. This swing arm allows the laser to read information from the centre to the edge of a disc, without having to interrupt the spinning of the disc itself.


The pits and lands themselves do not directly represent the zeros and ones of binary data. Instead, non-return-to-zero, inverted encoding is used: a change from pit to land or land to pit indicates a one, while no change indicates a series of zeros. There must be at least two and no more than ten zeros between each one, which is defined by the length of the pit. This in turn is decoded by reversing the eight-to-fourteen modulation used in mastering the disc, and then reversing the cross-interleaved Reed–Solomon coding, finally revealing the raw data stored on the disc. These encoding techniques (defined in the Red Book) were originally designed for CD Digital Audio, but they later became a standard for almost all CD formats (such as CD-ROM).


CDs are susceptible to damage during handling and from environmental exposure. Pits are much closer to the label side of a disc, enabling defects and contaminants on the clear side to be out of focus during playback. Consequently, CDs are more likely to suffer damage on the label side of the disc. Scratches on the clear side can be repaired by refilling them with similar refractive plastic or by careful polishing. The edges of CDs are sometimes incompletely sealed, allowing gases and liquids to corrode the metal reflective layer and to interfere with the focus of the laser on the pits. The fungus Geotrichum candidum, found in Belize, has been found to consume the polycarbonate plastic and aluminium found in CDs.


The digital data on a CD begins at the center of the disc and proceeds toward the edge, which allows adaptation to the different size formats available. Standard CDs are available in two sizes. By far, the most common is 120 millimetres (4.7 in) in diameter, with a 74- or 80-minute audio capacity and a 650 or 700 MiB (737,280,000-byte) data capacity. This capacity was reportedly specified by Sony executive Norio Ohga in May 1980 so as to be able to contain the entirety of the London Philharmonic Orchestra's recording of Beethoven's Ninth Symphony on one disc. This is a myth according to Kees Immink, as the code format had not yet been decided in May 1980. The adoption of EFM one month later would have allowed a playing time of 97 minutes for 120 mm diameter or 74 minutes for a disc as small as 100 mm. The 120 mm diameter has been adopted by subsequent formats, including Super Audio CD, DVD, HD DVD, and Blu-ray Disc. Eighty-millimeter discs ("Mini CDs") were originally designed for CD singles and can hold up to 24 minutes of music or 210 MiB of data but never became popular.[citation needed] Today, nearly every single is released on a 120 mm CD, called a Maxi single.[citation needed]


The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA) is described in a document produced in 1980 by the format's joint creators, Sony and Philips. The document is known colloquially as the Red Book CD-DA after the colour of its cover. The format is a two-channel 16-bit PCM encoding at a 44.1 kHz sampling rate per channel. Four-channel sound was to be an allowable option within the Red Book format, but has never been implemented. Monaural audio has no existing standard on a Red Book CD; thus, mono source material is usually presented as two identical channels in a standard Red Book stereo track (i.e., mirrored mono); an MP3 CD, however, can have audio file formats with mono sound.


Compact Disc + Graphics is a special audio compact disc that contains graphics data in addition to the audio data on the disc. The disc can be played on a regular audio CD player, but when played on a special CD+G player, it can output a graphics signal (typically, the CD+G player is hooked up to a television set or a computer monitor); these graphics are almost exclusively used to display lyrics on a television set for karaoke performers to sing along with. The CD+G format takes advantage of the channels R through W. These six bits store the graphics information.


SVCD has two-thirds the resolution of DVD, and over 2.7 times the resolution of VCD. One CD-R disc can hold up to 60 minutes of standard quality SVCD-format video. While no specific limit on SVCD video length is mandated by the specification, one must lower the video bit rate, and therefore quality, to accommodate very long videos. It is usually difficult to fit much more than 100 minutes of video onto one SVCD without incurring significant quality loss, and many hardware players are unable to play video with an instantaneous bit rate lower than 300 to 600 kilobits per second.


Photo CD is a system designed by Kodak for digitizing and storing photos on a CD. Launched in 1992, the discs were designed to hold nearly 100 high-quality images, scanned prints and slides using special proprietary encoding. Photo CDs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They are intended to play on CD-i players, Photo CD players and any computer with the suitable software irrespective of the operating system. The images can also be printed out on photographic paper with a special Kodak machine. This format is not to be confused with Kodak Picture CD, which is a consumer product in CD-ROM format.


The Red Book audio specification, except for a simple "anti-copy" statement in the subcode, does not include any copy protection mechanism. Known at least as early as 2001, attempts were made by record companies to market "copy-protected" non-standard compact discs, which cannot be ripped, or copied, to hard drives or easily converted to MP3s. One major drawback to these copy-protected discs is that most will not play on either computer CD-ROM drives or some standalone CD players that use CD-ROM mechanisms. Philips has stated that such discs are not permitted to bear the trademarked Compact Disc Digital Audio logo because they violate the Red Book specifications. Numerous copy-protection systems have been countered by readily available, often free, software.


A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.


The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. First conceived by Julius Lilienfeld in 1926 and practically implemented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley, the transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things. The transistor is on the list of IEEE milestones in electronics, and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement.


The thermionic triode, a vacuum tube invented in 1907, enabled amplified radio technology and long-distance telephony. The triode, however, was a fragile device that consumed a lot of power. Physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, which was intended to be a solid-state replacement for the triode. Lilienfeld also filed identical patents in the United States in 1926 and 1928. However, Lilienfeld did not publish any research articles about his devices nor did his patents cite any specific examples of a working prototype. Because the production of high-quality semiconductor materials was still decades away, Lilienfeld's solid-state amplifier ideas would not have found practical use in the 1920s and 1930s, even if such a device had been built. In 1934, German inventor Oskar Heil patented a similar device.


From November 17, 1947 to December 23, 1947, John Bardeen and Walter Brattain at AT&T's Bell Labs in the United States performed experiments and observed that when two gold point contacts were applied to a crystal of germanium, a signal was produced with the output power greater than the input. Solid State Physics Group leader William Shockley saw the potential in this, and over the next few months worked to greatly expand the knowledge of semiconductors. The term transistor was coined by John R. Pierce as a contraction of the term transresistance. According to Lillian Hoddeson and Vicki Daitch, authors of a biography of John Bardeen, Shockley had proposed that Bell Labs' first patent for a transistor should be based on the field-effect and that he be named as the inventor. Having unearthed Lilienfeld’s patents that went into obscurity years earlier, lawyers at Bell Labs advised against Shockley's proposal because the idea of a field-effect transistor that used an electric field as a "grid" was not new. Instead, what Bardeen, Brattain, and Shockley invented in 1947 was the first point-contact transistor. In acknowledgement of this accomplishment, Shockley, Bardeen, and Brattain were jointly awarded the 1956 Nobel Prize in Physics "for their researches on semiconductors and their discovery of the transistor effect."


In 1948, the point-contact transistor was independently invented by German physicists Herbert Mataré and Heinrich Welker while working at the Compagnie des Freins et Signaux, a Westinghouse subsidiary located in Paris. Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II. Using this knowledge, he began researching the phenomenon of "interference" in 1947. By June 1948, witnessing currents flowing through point-contacts, Mataré produced consistent results using samples of germanium produced by Welker, similar to what Bardeen and Brattain had accomplished earlier in December 1947. Realizing that Bell Labs' scientists had already invented the transistor before them, the company rushed to get its "transistron" into production for amplified use in France's telephone network.


Although several companies each produce over a billion individually packaged (known as discrete) transistors every year, the vast majority of transistors are now produced in integrated circuits (often shortened to IC, microchips or simply chips), along with diodes, resistors, capacitors and other electronic components, to produce complete electronic circuits. A logic gate consists of up to about twenty transistors whereas an advanced microprocessor, as of 2009, can use as many as 3 billion transistors (MOSFETs). "About 60 million transistors were built in 2002… for [each] man, woman, and child on Earth."


The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. It can produce a stronger output signal, a voltage or current, which is proportional to a weaker input signal; that is, it can act as an amplifier. Alternatively, the transistor can be used to turn current on or off in a circuit as an electrically controlled switch, where the amount of current is determined by other circuit elements.


There are two types of transistors, which have slight differences in how they are used in a circuit. A bipolar transistor has terminals labeled base, collector, and emitter. A small current at the base terminal (that is, flowing between the base and the emitter) can control or switch a much larger current between the collector and emitter terminals. For a field-effect transistor, the terminals are labeled gate, source, and drain, and a voltage at the gate can control a current between source and drain.


In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises, the emitter and collector currents rise exponentially. The collector voltage drops because of reduced resistance from collector to emitter. If the voltage difference between the collector and emitter were zero (or near zero), the collector current would be limited only by the load resistance (light bulb) and the supply voltage. This is called saturation because current is flowing from collector to emitter freely. When saturated, the switch is said to be on.


Providing sufficient base drive current is a key problem in the use of bipolar transistors as switches. The transistor provides current gain, allowing a relatively large current in the collector to be switched by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of transistor, and even for a particular type, varies depending on the collector current. In the example light-switch circuit shown, the resistor is chosen to provide enough base current to ensure the transistor will be saturated.


In a switching circuit, the idea is to simulate, as near as possible, the ideal switch having the properties of open circuit when off, short circuit when on, and an instantaneous transition between the two states. Parameters are chosen such that the "off" output is limited to leakage currents too small to affect connected circuitry; the resistance of the transistor in the "on" state is too small to affect circuitry; and the transition between the two states is fast enough not to have a detrimental effect.


Bipolar transistors are so named because they conduct by using both majority and minority carriers. The bipolar junction transistor, the first type of transistor to be mass-produced, is a combination of two junction diodes, and is formed of either a thin layer of p-type semiconductor sandwiched between two n-type semiconductors (an n–p–n transistor), or a thin layer of n-type semiconductor sandwiched between two p-type semiconductors (a p–n–p transistor). This construction produces two p–n junctions: a base–emitter junction and a base–collector junction, separated by a thin region of semiconductor known as the base region (two junction diodes wired together without sharing an intervening semiconducting region will not make a transistor).


BJTs have three terminals, corresponding to the three layers of semiconductor—an emitter, a base, and a collector. They are useful in amplifiers because the currents at the emitter and collector are controllable by a relatively small base current. In an n–p–n transistor operating in the active region, the emitter–base junction is forward biased (electrons and holes recombine at the junction), and electrons are injected into the base region. Because the base is narrow, most of these electrons will diffuse into the reverse-biased (electrons and holes are formed at, and move away from the junction) base–collector junction and be swept into the collector; perhaps one-hundredth of the electrons will recombine in the base, which is the dominant mechanism in the base current. By controlling the number of electrons that can leave the base, the number of electrons entering the collector can be controlled. Collector current is approximately β (common-emitter current gain) times the base current. It is typically greater than 100 for small-signal transistors but can be smaller in transistors designed for high-power applications.


In a FET, the drain-to-source current flows via a conducting channel that connects the source region to the drain region. The conductivity is varied by the electric field that is produced when a voltage is applied between the gate and source terminals; hence the current flowing between the drain and source is controlled by the voltage applied between the gate and source. As the gate–source voltage (VGS) is increased, the drain–source current (IDS) increases exponentially for VGS below threshold, and then at a roughly quadratic rate (IGS ∝ (VGS − VT)2) (where VT is the threshold voltage at which drain current begins) in the "space-charge-limited" region above threshold. A quadratic behavior is not observed in modern devices, for example, at the 65 nm technology node.


FETs are divided into two families: junction FET (JFET) and insulated gate FET (IGFET). The IGFET is more commonly known as a metal–oxide–semiconductor FET (MOSFET), reflecting its original construction from layers of metal (the gate), oxide (the insulation), and semiconductor. Unlike IGFETs, the JFET gate forms a p–n diode with the channel which lies between the source and drain. Functionally, this makes the n-channel JFET the solid-state equivalent of the vacuum tube triode which, similarly, forms a diode between its grid and cathode. Also, both devices operate in the depletion mode, they both have a high input impedance, and they both conduct current under the control of an input voltage.


FETs are further divided into depletion-mode and enhancement-mode types, depending on whether the channel is turned on or off with zero gate-to-source voltage. For enhancement mode, the channel is off at zero bias, and a gate potential can "enhance" the conduction. For the depletion mode, the channel is on at zero bias, and a gate potential (of the opposite polarity) can "deplete" the channel, reducing conduction. For either mode, a more positive gate voltage corresponds to a higher current for n-channel devices and a lower current for p-channel devices. Nearly all JFETs are depletion-mode because the diode junctions would forward bias and conduct if they were enhancement-mode devices; most IGFETs are enhancement-mode types.


The bipolar junction transistor (BJT) was the most commonly used transistor in the 1960s and 70s. Even after MOSFETs became widely available, the BJT remained the transistor of choice for many analog circuits such as amplifiers because of their greater linearity and ease of manufacture. In integrated circuits, the desirable properties of MOSFETs allowed them to capture nearly all market share for digital circuits. Discrete MOSFETs can be applied in transistor applications, including analog circuits, voltage regulators, amplifiers, power transmitters and motor drivers.


The Pro Electron standard, the European Electronic Component Manufacturers Association part numbering scheme, begins with two letters: the first gives the semiconductor type (A for germanium, B for silicon, and C for materials like GaAs); the second letter denotes the intended use (A for diode, C for general-purpose transistor, etc.). A 3-digit sequence number (or one letter then 2 digits, for industrial types) follows. With early devices this indicated the case type. Suffixes may be used, with a letter (e.g. "C" often means high hFE, such as in: BC549C) or other codes may follow to show gain (e.g. BC327-25) or voltage rating (e.g. BUK854-800A). The more common prefixes are:


The JEDEC EIA370 transistor device numbers usually start with "2N", indicating a three-terminal device (dual-gate field-effect transistors are four-terminal devices, so begin with 3N), then a 2, 3 or 4-digit sequential number with no significance as to device properties (although early devices with low numbers tend to be germanium). For example, 2N3055 is a silicon n–p–n power transistor, 2N1301 is a p–n–p germanium switching transistor. A letter suffix (such as "A") is sometimes used to indicate a newer variant, but rarely gain groupings.


Manufacturers of devices may have their own proprietary numbering system, for example CK722. Since devices are second-sourced, a manufacturer's prefix (like "MPF" in MPF102, which originally would denote a Motorola FET) now is an unreliable indicator of who made the device. Some proprietary naming schemes adopt parts of other naming schemes, for example a PN2222A is a (possibly Fairchild Semiconductor) 2N2222A in a plastic case (but a PN108 is a plastic version of a BC108, not a 2N108, while the PN100 is unrelated to other xx100 devices).


The junction forward voltage is the voltage applied to the emitter–base junction of a BJT in order to make the base conduct a specified current. The current increases exponentially as the junction forward voltage is increased. The values given in the table are typical for a current of 1 mA (the same values apply to semiconductor diodes). The lower the junction forward voltage the better, as this means that less power is required to "drive" the transistor. The junction forward voltage for a given current decreases with increase in temperature. For a typical silicon junction the change is −2.1 mV/°C. In some circuits special compensating elements (sensistors) must be used to compensate for such changes.


Because the electron mobility is higher than the hole mobility for all semiconductor materials, a given bipolar n–p–n transistor tends to be swifter than an equivalent p–n–p transistor. GaAs has the highest electron mobility of the three semiconductors. It is for this reason that GaAs is used in high-frequency applications. A relatively recent FET development, the high-electron-mobility transistor (HEMT), has a heterostructure (junction between different semiconductor materials) of aluminium gallium arsenide (AlGaAs)-gallium arsenide (GaAs) which has twice the electron mobility of a GaAs-metal barrier junction. Because of their high speed and low noise, HEMTs are used in satellite receivers working at frequencies around 12 GHz. HEMTs based on gallium nitride and aluminium gallium nitride (AlGaN/GaN HEMTs) provide a still higher electron mobility and are being developed for various applications.


Discrete transistors are individually packaged transistors. Transistors come in many different semiconductor packages (see image). The two main categories are through-hole (or leaded), and surface-mount, also known as surface-mount device (SMD). The ball grid array (BGA) is the latest surface-mount package (currently only for large integrated circuits). It has solder "balls" on the underside in place of leads. Because they are smaller and have shorter interconnections, SMDs have better high-frequency characteristics but lower power rating.


In the Pre-Modern era, many people's sense of self and purpose was often expressed via a faith in some form of deity, be that in a single God or in many gods. Pre-modern cultures have not been thought of creating a sense of distinct individuality, though. Religious officials, who often held positions of power, were the spiritual intermediaries to the common person. It was only through these intermediaries that the general masses had access to the divine. Tradition was sacred to ancient cultures and was unchanging and the social order of ceremony and morals in a culture could be strictly enforced.


The term "modern" was coined in the 16th century to indicate present or recent times (ultimately derived from the Latin adverb modo, meaning "just now). The European Renaissance (about 1420–1630), which marked the transition between the Late Middle Ages and Early Modern times, started in Italy and was spurred in part by the rediscovery of classical art and literature, as well as the new perspectives gained from the Age of Discovery and the invention of the telescope and microscope, expanding the borders of thought and knowledge.


The term "Early Modern" was introduced in the English language in the 1930s. to distinguish the time between what we call Middle Ages and time of the late Enlightenment (1800) (when the meaning of the term Modern Ages was developing its contemporary form). It is important to note that these terms stem from European history. In usage in other parts of the world, such as in Asia, and in Muslim countries, the terms are applied in a very different way, but often in the context with their contact with European culture in the Age of Discovery.


In the Contemporary era, there were various socio-technological trends. Regarding the 21st century and the late modern world, the Information age and computers were forefront in use, not completely ubiquitous but often present in daily life. The development of Eastern powers was of note, with China and India becoming more powerful. In the Eurasian theater, the European Union and Russian Federation were two forces recently developed. A concern for Western world, if not the whole world, was the late modern form of terrorism and the warfare that has resulted from the contemporary terrorist acts.


In Asia, various Chinese dynasties and Japanese shogunates controlled the Asian sphere. In Japan, the Edo period from 1600 to 1868 is also referred to as the early modern period. And in Korea, from the rising of Joseon Dynasty to the enthronement of King Gojong is referred to as the early modern period. In the Americas, Native Americans had built a large and varied civilization, including the Aztec Empire and alliance, the Inca civilization, the Mayan Empire and cities, and the Chibcha Confederation. In the west, the European kingdoms and movements were in a movement of reformation and expansion. Russia reached the Pacific coast in 1647 and consolidated its control over the Russian Far East in the 19th century.


In China, urbanization increased as the population grew and as the division of labor grew more complex. Large urban centers, such as Nanjing and Beijing, also contributed to the growth of private industry. In particular, small-scale industries grew up, often specializing in paper, silk, cotton, and porcelain goods. For the most part, however, relatively small urban centers with markets proliferated around the country. Town markets mainly traded food, with some necessary manufactures such as pins or oil. Despite the xenophobia and intellectual introspection characteristic of the increasingly popular new school of neo-Confucianism, China under the early Ming dynasty was not isolated. Foreign trade and other contacts with the outside world, particularly Japan, increased considerably. Chinese merchants explored all of the Indian Ocean, reaching East Africa with the treasure voyages of Zheng He.


The Qing dynasty (1644–1911) was founded after the fall of the Ming, the last Han Chinese dynasty, by the Manchus. The Manchus were formerly known as the Jurchens. When Beijing was captured by Li Zicheng's peasant rebels in 1644, the Chongzhen Emperor, the last Ming emperor, committed suicide. The Manchus then allied with former Ming general Wu Sangui and seized control of Beijing, which became the new capital of the Qing dynasty. The Mancus adopted the Confucian norms of traditional Chinese government in their rule of China proper. Schoppa, the editor of The Columbia Guide to Modern Chinese History argues, "A date around 1780 as the beginning of modern China is thus closer to what we know today as historical 'reality'. It also allows us to have a better baseline to understand the precipitous decline of the Chinese polity in the nineteenth and twentieth centuries."


Society in the Japanese "Tokugawa period" (Edo society), unlike the shogunates before it, was based on the strict class hierarchy originally established by Toyotomi Hideyoshi. The daimyo, or lords, were at the top, followed by the warrior-caste of samurai, with the farmers, artisans, and traders ranking below. In some parts of the country, particularly smaller regions, daimyo and samurai were more or less identical, since daimyo might be trained as samurai, and samurai might act as local lords. Otherwise, the largely inflexible nature of this social stratification system unleashed disruptive forces over time. Taxes on the peasantry were set at fixed amounts which did not account for inflation or other changes in monetary value. As a result, the tax revenues collected by the samurai landowners were worth less and less over time. This often led to numerous confrontations between noble but impoverished samurai and well-to-do peasants, ranging from simple local disturbances to much bigger rebellions. None, however, proved compelling enough to seriously challenge the established order until the arrival of foreign powers.


On the Indian subcontinent, the Mughal Empire ruled most of India in the early 18th century. The "classic period" ended with the death and defeat of Emperor Aurangzeb in 1707 by the rising Hindu Maratha Empire, although the dynasty continued for another 150 years. During this period, the Empire was marked by a highly centralized administration connecting the different regions. All the significant monuments of the Mughals, their most visible legacy, date to this period which was characterised by the expansion of Persian cultural influence in the Indian subcontinent, with brilliant literary, artistic, and architectural results. The Maratha Empire was located in the south west of present-day India and expanded greatly under the rule of the Peshwas, the prime ministers of the Maratha empire. In 1761, the Maratha army lost the Third Battle of Panipat which halted imperial expansion and the empire was then divided into a confederacy of Maratha states.


The development of New Imperialism saw the conquest of nearly all eastern hemisphere territories by colonial powers. The commercial colonization of India commenced in 1757, after the Battle of Plassey, when the Nawab of Bengal surrendered his dominions to the British East India Company, in 1765, when the Company was granted the diwani, or the right to collect revenue, in Bengal and Bihar, or in 1772, when the Company established a capital in Calcutta, appointed its first Governor-General, Warren Hastings, and became directly involved in governance.