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Chandrayaan-1

Chandrayaan-1

Chandrayaan I (Means Journey to Moon (Chandra=Moon, yaan=Journey) in Sanskrit and Hindi languages) is the name for a mission of the Indian space agency to send an unmanned spacecraft to the Moon which will then take a polar orbit around. The spacecraft will be launched by a modified version of India's indigenous Polar Satellite Launch Vehicle. The remote sensing satellite will weigh 1050 kg (523 kg initial orbit mass and 440 kg dry mass) and carries high resolution remote sensing equipment for visible, near infrared, soft and hard X-ray frequencies. During two years, it is supposed to survey the lunar surface to produce a complete map of its chemical characteristics and 3-dimensional topography. Especially the polar regions are of interest, as they might contain water ice. In September 2004, the Indian Space Research Organization (ISRO) announced in a press statement that planning has now made enough progress that they are confident that the mission will take place in 2007 or 2008. They estimate the cost to be only INR 3.8 billion (US$ 83 million). The idea of a manned mission had been ruled out as considered to be too costly (INR 100 billion = US$ 2.2 billion). The mission includes cooperation with other space agencies such as NASA and ESA, including the flight of spare SMART-1 instruments.

External links

- [http://www.isro.org/chandrayaan-1/announcement.htm Chrandrayaan-1 Announcement of Opportunity] and [http://www.isro.org/chandrayaan-1/ home page] from ISRO
- [http://www.esa.int/esaCP/SEMRXIRMD6E_index_0.html European Space Agency to cooperate with India's first lunar mission]
- [http://aviris.jpl.nasa.gov/html/m3factsheet.pdf M3 fact sheet]
- [http://www.space.com/missionlaunches/india_moon_050314.html space.com: U.S. radar on Chandrayaan-1?] (14.03.2005) Category:Indian space program Category:Lunar spacecraft

Sanskrit

Sanskrit ( संस्कृतम्) is a classical language of India and a liturgical language of Hinduism, Buddhism, and Jainism. It has a position in India and Southeast Asia similar to that of Latin and Greek in Medieval Europe, and is a central part of Hindu tradition. Sanskrit is one of the 22 official languages of India. Sanskrit is taught in schools and households throughout India, as a second language. Some Brahmins even identify it as their mother tongue. According to recent reports, it is being revived as a vernacular in the village of Mattur near Shimoga in Karnataka [http://timesofindia.indiatimes.com/articleshow/msid-1199965,curpg-1.cms]. Sanskrit is mostly used as a ceremonial language in Hindu religious rituals in the forms of hymns and mantras. Its pre-classical form of Vedic Sanskrit, the liturgical language of the Vedic religion, is one of the earliest attested members of the Indo-European language family, its most archaic text being the Rigveda. The scope of this article is that of Classical Sanskrit as laid out in the grammar of Panini, roughly around 500 BC. Most Sanskrit texts available today were transmitted orally for several centuries before they were written down in medieval India.

History

500 BC script, Bihar or Nepal, 11th century.]] The word means "refined, consecrated, sanctified". The language referred to as "the refined language" has by definition always been a 'high' language, used for religious and scientific discourse and contrasted with the languages spoken by the people. The oldest surviving Sanskrit grammar is 's ("Eight-Chapter Grammar") dating to ca. the 5th century BC. It is essentially a prescriptive grammar, i. e. an authority that defines (rather than describes) correct Sanskrit, although it contains descriptive parts, mostly to account for Vedic forms that had already passed out of use in Panini's time. Almost every student of Sanskrit hears the traditional story that Sanskrit was created and then refined over many generations (traditionally more than a thousand years) until it was considered complete and perfect. When the term arose in India, "Sanskrit" was not thought of as a specific language set apart from other languages (the people of the time regarded languages more as dialects), but rather as a particularly refined manner of speaking, bearing a similar relation to common language that "Standard" English bears to dialects spoken in the United Kingdom or United States. Knowledge of Sanskrit was a marker of social class and educational attainment, and was taught through close analysis of Sanskrit grammarians such as Pāṇini. This form of the language evolved out of the earlier "Vedic" form, and scholars often distinguish Vedic Sanskrit and Classical Sanskrit as separate languages. However, they are extremely similar in many ways and differ mostly in a few points of phonology, vocabulary, and grammar. But some think that in ancient India there were various dialects of Sanskrit, and Classical Sanskrit is one of these dialects, and Vedic is an earlier stage of another of these dialects; the Vedic dialect had more tendency to change Indo-European [l] into [r]; Vedic changed [d.] and [d.h] into [l.] and [l.h] (with retroflex l) between vowels. Vedic is the language of the Vedas, the earliest sacred texts of India and the base of the Hindu religion. The earliest of the Vedas, the Rigveda, was composed by many authors over hundreds, and probably thousands of years. Recent scholarship traces the composition of the Rigveda to the 3rd or even 4th millennium BCE at a period before the Saraswati River dried up. The Rigveda mentions the Saraswati as the mightiest of all rivers (RV 7.95.2). By 2,500 BCE it had disappeared. The Vedic form of Sanskrit survived until the middle of the first millennium BC. It is around this time that Sanskrit made the transition from a first language to a second language of religion and learning, marking the beginning of the Classical period. A form of Sanskrit called Epic Sanskrit is seen in the Mahabharata and other Hindu epics. This includes more "prakritisms" (borrowings from common speech) than Classical Sanskrit proper. There is also a language dubbed "Buddhist Hybrid Sanskrit" by scholars, which is actually a prakrit ornamented with Sanskritized elements, perhaps for purposes of ostentation (see also termination of spoken Sanskrit). There is a strong relationship between the various forms of Sanskrit and the Middle Indo-Aryan "Prakrits", or vernacular languages (in which, among other things, most early Jain and Buddhist texts are written), and the modern Indo-Aryan languages. The Prakrits are probably descended from Vedic, and there is mutual interchange between later forms of Sanskrit and various Prakrits. There has also been reciprocal influence between Sanskrit and the Dravidian languages. European scholarship in Sanskrit, begun by Heinrich Roth and Johann Ernst Hanxleden, led to the proposal of the Indo-European language family by Sir William Jones, and thus played an important role in the development of Western linguistics. Indeed, linguistics (along with phonology, etc.) first arose among Indian grammarians who were attempting to catalog and codify Sanskrit's rules. Modern linguistics owes a great deal to these grammarians, and to this day, key terms for compound analysis are taken from Sanskrit.

Phonology and writing system

See also Shiva Sutra. Classical Sanskrit has 48 phonemes (Vedic Sanskrit has 49). The sounds are described here in their traditional order: vowels, stops and nasals (starting in the back of the mouth and moving forward), and finally the liquids and sibilants. (Note: The long vowels are held about twice as long as their short counterparts. Also, there exists a third, extra-long length for most vowels, which is used in various cases, but particularly in the vocative.)

Simple vowels

Unlike in English, , , and are treated as vowels. Some grammarians mention ॡ , a longer version of , but this does not actually occur in Sanskrit and seems to have been created by analogy with the other vowels. Technically speaking, never occurs in the language at a purely phonetic level. It, however is seen in the genitive plural of vocalic-r stems (मातृ mātṛ mother; पितृ pitṛ father; gen.pl.मातॄणाम् and पितॄणाम् mātṝṇām and pitṝṇām etc.) and explains irregularities in the conjugation of verbs such as d "to tear", and k "to scatter".

Diphthongs (combinations of simple vowels)

Vowels can be nasalized.

Consonants

There is also the anusvāra (), which often appears as nasalization of the preceding vowel or as a nasal homorganic to the following consonant.

Pitch

Vedic Sanskrit is a pitch accent language. Native grammarians define three tones (svara): udātta = 'raised', anudātta = 'not raised', and svarita = 'sounded'. The udātta syllable corresponds to the original Indo-European stress. The svarita is usually the next syllable after an udātta. Probably when the Rigveda was written down, the pitch of speech rose through the udātta and came back down through the following svarita. A svarita which is not next after an udātta is called an "independent svarita". In transliteration udātta is marked with acute accent (´) and independent svarita with a grave accent (`). Independent svarita occurs only where its udātta was lost because of vowel sandhi. Classical Sanskrit is usually pronounced with a stress accent decided by the syllable length pattern of each word.

Sandhi

Sanskrit has an elaborate set of phonological rules called sandhi and which are expressed in writing (except in so-called pada texts). Sandhi refers to combination of words when they are spoken with each other without a gap. Since the word scheme is based on pronunciation, this is no exception. Sandhi rules define how the entire word or phrase sounds when two words are combined or merged. Almost always, the new word sounds like the two words spoken one after other except for euphonic changes at the point where the first word ends and the second one starts. This change depends on the sound with which the first word ends and the sound with which the second word starts. These sounds also form the basis of classification of sandhis. The effects of Sandhi have been carefully observed and described, leading to codified rules of combination. For example, when saying one word ending in i followed by another starting in u, these will be combined into yu. These sandhi rules are not always obeyed in the Vedas. is a combination of two or more words, or sometimes even a phrase, like 'newborn' is for 'newly born'. The meaning of a is normally clear from the itself, though some of the have a meaning very different from their constituent words. These are normally used to refer to some personality, deity or thing by one of its well known characteristics. are also categorized according to the kind of meaning they have and the constituent word that dominates the meaning. plays a key role in many cases, especially in certain expressions. does not have any distortion in the words, although sometimes prefixes and suffixes are used to impart a certain type of meanings to the words. A sandhi always consists of two meaningful words while all constituent words of a may not be meaningful individually. A sandhi may be difficult to understand for a person who is inexperienced in Sanskrit or has a poor vocabulary. It is same with , but they are much easier to understand as they are mostly used in some fixed formats and meanings. Sandhi and add beauty to the language and are extensively used by poets. When a sandhi can be broken in more than one way or a can be interpreted in more than one way, they can be used as puns. There are many examples of such uses in Sanskrit literature.

Script

Veda manuscript in the Sharada script (17th or 18th century)]] Sanskrit historically has had no single script associated with it. Ashoka used the Brahmi script for his pillar inscriptions (which were not in Sanskrit, but in Prakrit dialects and other languages). Roughly contemporary with the Brahmi, the Kharosthi script was used. Later (ca. 4th to 8th centuries AD) the Gupta script, derived from Brahmi, became prevalent. From ca. the 8th century, the Sharada script evolved out of the Gupta script, and was mostly displaced in its turn by Devanagari from ca. the 12th century, with intermediary stages such as the Siddham script. Other scripts used include Kannada in the South, Grantha in Tamil speaking regions, Bengali, and other North Indian scripts in other regions. From the late Middle Ages, and especially in modern times, the Devanagari (meaning "as used in the city of the Gods") script has become the most widely used and associated with Sanskrit. Occasionally, in regions of India where Devanagari is not the script of the vernacular (as it is with Hindi or Marathi) one will find texts still written in the local script. Writing was introduced relatively late to India, and it did not immediately become important since oral learning was the primary means of transmitting knowledge. Rhys Davids suggests that writing may have been introduced from the Middle East by traders, but Sanskrit, which had been used exclusively in sacred contexts, remained a purely oral language until well into India's classical age. It is interesting to note the importance that Sanskrit orthography and Vedic philosophy of sound play in Hindu symbolism, as the varnamala, or sound-garland/alphabet, of 51 letters is also seen to be represented by the 51 skulls of Kali. In the Upanishads, the transcendent-immanent nature of Brahman is represented by the half-matra, or sphota of sound that is inherent to a beat of sound in the Sanskrit system. Since the 19th century, Sanskrit has also been transliterated using the Latin alphabet. Most commonly used today is the IAST (International Alphabet of Sanskrit Transliteration), which has been the academic standard since 1912. Other transliteration schemes have evolved due to difficulties representing Sanskrit characters in computer systems. These include Harvard-Kyoto that was used earlier, and ITRANS, a lossless transliteration scheme that is used widely on the Internet (especially Usenet). For scholarly work, Devanagari has generally been preferred for the transcription and reproduction of whole texts and lengthy excerpts; however, references to individual words and names in texts composed in European languages are usually represented using Roman transliteration.

Grammar

Grammatical tradition

Panini (scholar), Shiva Sutra, Astadhyayi, Dhatupatha, Patanjali, Varadaraja, Laghukaumudi.

Verbs

Classification of verbs

Sanskrit has ten classes of verbs divided into in two broad groups: athematic and thematic. The thematic verbs are so called because an a, called the theme vowel, is inserted between the stem and the ending. This serves to make the thematic verbs generally more regular. Exponents used in verb conjugation include prefixes, suffixes, infixes, and reduplication. Vowel gradation is also very common; every root has (not necessarily all distinct) zero, guṇa, and vṛddhi grades. If V is the vowel of the zero grade, the guṇa-grade vowel is traditionally thought of as a + V, and the vṛddhi-grade vowel as ā + V.

Tense systems

The verbs tenses (a very inexact application of the word, since more distinctions than simply tense are expressed) are organized into four 'systems' (as well as gerunds and infinitives, and such creatures as intensives/frequentatives, desideratives, causatives, and benedictives derived from more basic forms) based on the different stem forms (derived from verbal roots) used in conjugation. There are four tense systems:
- Present (Present, Imperfect, Imperative, Optative)
- Perfect
- Aorist
- Future (Future, Conditional)

Present system

The present system includes the present and imperfect tenses, the optative and imperative moods, as well as some of the remnant forms of the old subjunctive. The tense stem of the present system is formed in various ways. The numbers are the native grammarians' numbers for these classes. For athematic verbs, the present tense stem may be formed through:
- 2) No modification at all, for example ad from ad 'eat'.
- 3) Reduplication prefixed to the root, for example juhu from hu 'sacrifice'.
- 7) Infixion of na or n before the final root consonant (with appropriate sandhi changes), for example rundh or ruṇadh from rudh 'obstruct'.
- 5) Suffixation of nu (guṇa form no), for example sunu from su 'press out'.
- 8) Suffixation of u (guṇa form o), for example tanu from tan 'stretch'. For modern linguistic purposes it is better treated as a subclass of the 5th. tanu derives from tnnu, which is zero-grade for
- tannu, because in Indo-European [m] and [n] could be vowels, which in Sanskrit (and Greek) change to [a]. Most members of the 8th class arose this way; kar = "make", "do" was 5th class in Vedic (krnoti = "he makes"), but shifted to the 8th class in Classical Sanskrit (karoti = "he makes")
- 9) Suffixation of nā (zero-grade nī or n), for example krīṇa or krīṇī from krī 'buy'. For thematic verbs, the present tense stem may be formed through:
- 1) Suffixation of the thematic vowel a with guṇa strengthening, for example, bháva from bhū 'be'.
- 6) Suffixation of the thematic vowel a with a shift of accent to this vowel, for example tudá from tud 'thrust'.
- 4) Suffixation of ya, for example dī́vya from div 'play'. The tenth class described by native grammarians refers to a process which is derivational in nature, and thus not a true tense-stem formation.

Perfect system

The perfect system includes only the perfect tense. The stem is formed with reduplication as with the present system. The perfect system also produces separate "strong" and "weak" forms of the verb — the strong form is used with the singular active, and the weak form with the rest.

Aorist system

The aorist system includes aorist proper (with past indicative meaning, e.g. abhūḥ "you were") and some of the forms of the ancient injunctive (used almost exclusively with mā in prohibitions, e.g. mā bhūḥ "don't be"). The principal distinction of the two is presence/absence of an augment - a- prefixed to the stem. The aorist system stem actually has three different formations: the simple aorist, the reduplicating aorist (semantically related to the causative verb), and the sibilant aorist. The simple aorist is taken directly from the root stem (e.g. bhū-: a-bhū-t "he was"). The reduplicating aorist involves reduplication as well as vowel reduction of the stem. The sibilant aorist is formed with the suffixation of s to the stem.

Future system

The future system is formed with the suffixation of sya or iṣya and guṇa.

Verbs: Conjugation

Each verb has a grammatical voice, whether active, passive or middle. There is also an impersonal voice, which can be described as the passive voice of intransitive verbs. Sanskrit verbs have an indicative, an optative and an imperative mood. Older forms of the language had a subjunctive, though this had fallen out of use by the time of Classical Sanskrit.

Basic conjugational endings

Conjugational endings in Sanskrit convey person, number, and voice. Different forms of the endings are used depending on what tense stem and mood they are attached to. Verb stems or the endings themselves may be changed or obscured by sandhi. Primary endings are used with present indicative and future forms. Secondary endings are used with the imperfect, conditional, aorist, and optative. Perfect and imperative endings are used with the perfect and imperative respectively.

Present system conjugation

Conjugation of the present system deals with all forms of the verb utilizing the present tense stem (explained under Tense Stems above). This includes the present tense of all moods, as well as the imperfect indicative.

Athematic inflection

The present system differentiates strong and weak forms of the verb. The strong/weak opposition manifests itself differently depending on the class:
- The root and reduplicating classes (2 & 3) are not modified in the weak forms, and receive guṇa in the strong forms.
- The nasal class (7) is not modified in the weak form, extends the nasal to ná in the strong form.
- The nu-class (5) has nu in the weak form and nó in the strong form.
- The nā-class (9) has nī in the weak form and nā́ in the strong form. nī disappears before vocalic endings. The present indicative takes primary endings, and the imperfect indicative takes secondary endings. Singular active forms have the accent on the stem and take strong forms, while the other forms have the accent on the endings and take weak forms. The optative takes secondary endings. yā is added to the stem in the active, and ī in the passive. The imperative takes imperative endings. Accent is variable and affects vowel quality. Forms which are end-accented trigger guṇa strengthening, and those with stem accent do not have the vowel affected.

Nominal inflection

Sanskrit is a highly inflected language with three grammatical genders (masculine, feminine, neuter) and three numbers (singular, plural, dual). It has eight cases: nominative, vocative, accusative, instrumental, dative, ablative, genitive, and locative. The number of actual declensions is debatable. In this article they are divided into five declensions. Which declension a noun belongs to is determined largely by form.

a-stems

A-stems comprise the largest class of nominals. As a rule nouns belonging to this class, ending in short-A, are either masculine or neuter. Nouns ending in long-A tend to be feminine. A-stem adjectives take the masculine and neuter in short-A, and feminine in long-A.

i- and u-stems

Long Vowel-stems

ṛ-stems

ṛ-stems are predominantly agental derivatives like dātṛ 'giver', though also include kinship terms like pitṛ́ 'father', mātṛ́ 'mother', and svásṛ 'sister'. See also Devi inflection, Vrkis inflection.

Personal Pronouns and Determiners

The first and second person pronouns are declined for the most part alike, having by analogy assimilated themselves with one another. Note: Where two forms are given, the second is enclitic and an alternative form. Ablatives in singular and plural may be extended by the syllable -tas; thus mat or mattas, asmat or asmattas. The demonstrative ta, declined below, also functions as the third person pronoun.

Compounds

One other notable feature of the nominal system is the very common use of nominal compounds, which may be huge (10+ words) as in some modern languages such as German. Nominal compounds occur with various structures, however morphologically speaking they are essentially the same. Each noun (or adjective) is in its (weak) stem form, with only the final element receiving case inflection. Some examples of nominal compounds include: 1. (co-ordinative) ::These consist of two or more noun stems, connected in sense with 'and', e.g. matara-pitara 'Mother and Father'. Due to these compounds having more than one noun in them, they must be in the dual or plural. 2. (possessive) ::Bahuvrīhi, or "much-rice", denotes a rich person—one who has much rice. Bahuvrīhi compounds refer (by example) to a compound noun with no head -- a compound noun that refers to a thing which is itself not part of the compound. For example, "low-life" and "block-head" are bahuvrihi compounds, since a low-life is not a kind of life, and a block-head is not a kind of head. (And a much-rice is not a kind of rice.) Compare with more common, headed, compound nouns like "fly-ball" (a kind of ball) or "alley cat" (a kind of cat). Bahurvrīhis can often be translated by "possessing..." or "-ed"; for example, "possessing much rice", or "much riced". 3. (determinative) ::There are many tatpuruas (one for each of the nominal cases, and a few others besides); in a tatpurua, the first component is in a case relationship with another. For example, a doghouse is a dative compound, a house for a dog. It would be called a "caturtitatpurua" (caturti refers to the fourth case—that is, the dative). Incidentally, "tatpurua" is a tatpurua ("this man"—meaning someone's agent), while "caturtitatpurua" is a karmadhārya, being both dative, and a tatpurua. An easy way to understand it is to look at English examples of tatpuruas: "battlefield", where there is a genitive relationship between "field" and "battle", "a field of battle"; other examples include instrumental relationships ("thunderstruck") and locative relationships ("towndwelling"). 4. (descriptive) ::The relation of the first member to the last is appositional, attributive or adverbial, e. g. uluka-yatu (owl+demon) is a demon in the shape of an owl. 5. (iterative) ::Repetition of a word expresses repetitiveness, e. g. dive-dive 'day by day', 'daily'.

Syntax

Word order is free with tendency toward SOV.

Numerals

The numbers from one to ten are: The numbers one through four are declined. Éka is declined like a pronomial adjective, though the dual form does not occur. Dvá appears only in the dual. Trí and catúr are declined irregularly:

Influences

Modern-day India

Sanskrit's greatest influence, presumably, is that which it exerted on languages that grew from its vocabulary and grammatical base. Especially among elite circles in India, Sanskrit is prized as a storehouse of scripture and the language of prayers in Hinduism. Like Latin's influence on European languages, Sanskrit has influenced most Indian languages. While vernacular prayer is common, Sanskrit mantras are recited by millions of Hindus and most temple functions are conducted entirely in Sanskrit, often Vedic in form. Most higher forms of Indian vernacular languages like Bengali, Gujarati, Marathi, Telugu and Hindi, often called 'shuddha' (pure, higher) are much more heavily Sanskritized. Of modern day Indian languages, while Hindi tends to be, in spoken form, more heavily weighted with Arabic and Persian influence, Bengali and Marathi still retain a largely Sanskrit vocabulary base. The national anthem, Jana Gana Mana is higher form of Bengali, so Sanskritized as to be archaic in modern usages. The national song of India Vande Mataram which is originally a poem - composed by Bankim Chandra Chattopadhyay and taken from his book called 'Aanandmath', is in pure Sanskrit. Malayalam, which is spoken in the Kerala state of India, also combines a great deal of Sanskrit vocabulary with Tamil (Dravidian) grammatical structure. Kannada, another South Indian language, also contains Sanskrit vocabulary. But as a medium of spiritual instruction for Hindus in India, Sanskrit is still prized and widespread. Sanskrit words are found in many other present-day non-Indian languages. For instance, the Thai language contains many loan words from Sanskrit. For example, in Thai, the Rāvana - the emperor of Sri Lanka is called 'Thoskonth' which is clearly a derivation of his Sanskrit name 'Dashakanth' (of ten necks). And ranged as far as the Philippines, e.g., Tagalog 'gurò' from 'Guru', or 'teacher', with the Hindu seafarers who traded there.

Attempts at revival

Of late, there have been attempts to revive the speaking of this ancient tongue among people, so that vast literature available in Sanskrit can be made easily available to everyone. The CBSE (Central Board of Secondary Education) in India has made Sanskrit a third language in the schools it governs. In such schools, learning Sanskrit is an option for grades 5 to 8. An option between Sanskrit and Hindi (or many other local languages) as a second language exists for grades 9 and 10. Many organizations like the Samskrta Bharati are conducting Speak Sanskrit workshops to popularize the language. About four million people are claimed to have acquired the ability to speak Sanskrit. Sanskrit is claimed to be spoken natively by the population in Mattur, a village in central Karnataka. Inhabitants, of all castes, learn Sanskrit starting in childhood and converse in the language. Even the local Muslims speak and converse in Sanskrit. Historically, the village was given by king Krishnadevaraya of the Vijayanagara Empire to Vedic scholars and their families. People in his kingdom spoke Kannada and Tuluva.

Interactions with Sino-Tibetan languages

Sanskrit and related languages have also influenced their Sino-Tibetan-speaking neighbors to the north through the spread of Buddhist texts in translation. Buddhism was spread to China by Mahayanist missionaries mostly through translations of Buddhist Hybrid Sanskrit and classical Sanskrit texts, and many terms were transliterated directly and added to the Chinese vocabulary. (Although Buddhist Hybrid Sanskrit is not Sanskrit, properly speaking, its vocabulary is substantially the same, both because of genetic relationship, and because of conscious imitation on the part of composers. Buddhist texts composed in Sanskrit proper were primarily found in philosophical schools like the Madhyamaka.)

Western vogue for Sanskrit

At the end of the introduction to The World as Will and Representation, Arthur Schopenhauer claimed that the rediscovery of the ancient Indian tradition would be one of the great events in the history of the West. Goethe borrowed from Kalidasa for the Vorspiel auf dem Theater in Faust. Goethe and Schopenhauer were riding a crest of scholarly discovery, most notably the work done by Sir William Jones. (Goethe likely read Kalidasa's The Recognition of Sakuntala in Jones' translation.) However, the discovery of the world of Sanskrit literature moved beyond German and British scholars and intellectuals — Henry David Thoreau was a sympathetic reader of the Bhagavad Gita — and even beyond the humanities. In the early days of the Periodic Table, scientists referred to as yet undiscovered elements with the use of Sanskrit prefixes (see Mendeleev's predicted elements). The nineteenth century was a golden age of Western Sanskrit scholarship, and many of the giants of the field (Whitney, Macdonnell, Monier-Williams, Grassmann) knew each other personally. Perhaps the most commonly known example of Sanskrit in the West was also the last gasp of its vogue. T.S. Eliot, a student of Indian Philosophy and Lanham's, ended The Waste Land with Sanskrit: "Shantih Shantih Shantih".

Computational linguistics

There have been suggestions to use Sanskrit as a metalanguage for knowledge representation in e.g. machine translation, and other areas of natural language processing because of its highly regular structure ([http://www.gosai.com/science/sanskrit-nasa.html The AI Magazine, Spring, 1985 #39]). This is due to Classical Sanskrit being a regularized, prescriptivist form abstracted from the much more irregular and richer Vedic Sanskrit. This levelling of the grammar of Classical Sanskrit occurred during the Brahmana phase, after the language had fallen out of popular use, arguably qualifying Classical Sanskrit as an early engineered language.

References

- The Sanskrit Language - T. Burrow - ISBN 8120817672
- Sanskrit Grammar - William D. Whitney - ISBN 8185557594
- Sanskrit Pronunciation - Bruce Cameron - ISBN 1557000212
- "Teach Yourself Sanskrit" - Prof. M. Coulson - ISBN 0340859903
- "A Sanskrit Grammar for Students" - A.A. Macdonell - ISBN 8124600945

External links

- [http://sanskrit.farfromreal.com Discover Sanskrit] A concise study of the Sanskrit language
- [http://bhagavata.org/glossary/ Lexicon] of Names, Essential terms and Sanskrit Words to the S'rîmad Bhâgavatam and the Bhagavad Gîtâ
- [http://bhagavata.org/downloads/SanskritDictionary.html Sanskrit-English dictionary] list of 13.000 basic-terms
- [http://webapps.uni-koeln.de/tamil/ Sanskrit, Tamil and Pahlavi Dictionaries] Monier-Williams dictionary online
- [http://bhagavata.org/downloads/sanskritgrammar.pdf Harivenu Dâsa - An Introductory Course based on S'rîla Jîva Gosvâmî's Grammar] a vaishnava version of Pânini's grammar: (pdf-file)
- [http://www.alkhemy.com/sanskrit/dict/dictall.txt Online Sanskrit Dictionary]
- [http://www.warnemyr.com/skrgram/ An Analytical Cross Referenced Sanskrit Grammar] By Lennart Warnemyr. Phonology, morphology and syntax, written in a semiformal style with full paradigms.
- [http://www.swargarohan.org/Glossary.htm Spiritual Sanskrit-English Dictionary]
- [http://www.lioncity.net/buddhism/index.php?showforum=51 Sanskrit Discussion Forum]
- [http://sanskrit.gde.to/ Sanskrit Documents] Documents in ITX format of Upanishads, Stotras etc. and a metasite with links to translations, dictionaries, tutorials, tools and other Sanskrit resources.
- [http://www.balendu.com Free Sanskrit Word Processor: Madhyam] developed by Balendu Sharma Dadhich
- [http://www.sanskritweb.net Sanskritweb] Freely downloadable Sanskrit fonts and Sanskrit texts
- [http://www.geocities.com/giirvaani/ GiirvaaNi - Sanskrit Classical Literature with translation]
- [http://ds.dial.pipex.com/town/avenue/xha71/pow2.htm The earliest dated illustrated Sanskrit manuscript in the world]
- [http://www.arts.cuhk.edu.hk/cgi-bin/agrep-lindict?query=Sanskr.&category=full&boo=no&ignore=on&substr=on&order=all A list of Chinese words originated from Sanskrit]
- [http://www.uni-koeln.de/phil-fak/indologie/tamil/mwd_search.html Monier-Williams Dictionary - Searchable]
- [http://indica-et-buddhica.org/?q=node/8 Monier-Williams' Sanskrit-English Dictionary: DICT & HTML Downloadable Versions]
- [http://indica-et-buddhica.org/dict/lexica Indica-et-Buddhica.org Lexica (searchable Monier-Williams included)]
- [http://www.thekrishnastore.com/Detail.bok?no=2295&bar= Monier-Williams Dictionary - Searchable Digital Facsimile Edition] Freeware CD
- [http://www.ibiblio.org/sripedia/ebooks/mw/0000/ Monier-Williams Dictionary - Printable]
- [http://www.samskrita-bharati.org/ Samskrita Bharati]
- [http://sanskritlinks.blogspot.com Sanskrit Studies, Links and Information]
- [http://www.ece.lsu.edu/kak/bhate.pdf pAnini’s Grammar and Computer Science]
- [http://www.ethnologue.com/show_language.asp?code=san Ethnologue's Sanskrit report]
- [http://www.americansanskrit.com/ American Sanskrit Institute]
- [http://www.atmajyoti.org/sw_glossary.asp A brief Sanskrit Glossary] Lists commonly used words in spiritual writings
- [http://www.iit.edu/~laksvij/language/hindi.html Tranliterator] Transliterates from romanized to Unicode Sanskrit transliterator.
- [http://www.proz.com/sanskrit-to-english-translation-services Sanskrit Translations]
- [http://www.sanskrit-lamp.org/ A Sanskrit Tutor]
- [http://www.sanskrit-sanscrito.com.ar/ Sanskrit & Sánscrito] Sanskrit language, Yoga, Indian philosophies, blog, names, names of hatha yoga postures, Directory of Free Sanskrit Links, translations and much more (English-Spanish).
- [http://www.atma.ca/] Sanskrit web site, called ATMA (french) Category:Classical languages Category:Languages of India Category:Ancient languages
- ko:산스크리트어 ms:Bahasa Sanskrit ja:サンスクリット th:ภาษาสันสกฤต

India

The Republic of India is a country in South Asia which comprises of the majority of the Indian subcontinent. India has a coastline which stretches over seven thousand kilometres, and shares its borders with Pakistan to the west, the People's Republic of China, Nepal, and Bhutan to the northeast, and Bangladesh and Myanmar on the east. On the Indian Ocean, it is adjacent to the island nations of the Maldives on the southwest, Sri Lanka on the south, and Indonesia on the southeast. India also claims a border with Afghanistan to the northwest. India is the fourth largest economy in the world in terms of purchasing power parity. It is the second most populous country in the world, with a population of over one billion, and is the seventh largest country by geographical area. It is home to some of the most ancient civilizations, and a centre of important historic trade routes. Four major world religions: Hinduism, Buddhism, Jainism and Sikhism have originated from India. Formerly a major part of the British Empire as the British Raj before gaining independence in 1947, during the past twenty years the country has grown significantly, especially in its economic and military spheres, regionally as well as globally. The name India , is derived from the Old Persian version of Sindhu, the historic local appellation for the river Indus; see Origin of India's name. The Constitution of India and general usage also recognises Bharat ( ), which is derived from the Sanskrit name of an ancient Hindu king, whose story is to be found in the Mahabharata, as an official name of equal status. A third name, Hindustan ( ) , or Land of the Hindus in Persian, has been used since the twelfth century, though its contemporary use is unevenly applied due to domestic disputes over its representiveness as a national signifier.

History

Stone Age rock shelters with paintings at Bhimbetka in Madhya Pradesh are the earliest known traces of human life in India. The first known permanent settlements appeared 9,000 years ago and developed into the Indus Valley Civilisation, which peaked between 2600 BC and 1900 BC. It was followed by the Vedic Civilisation. From around 550 BC onwards, many independent kingdoms came into being. In the north, the Maurya dynasty, which included Ashoka, contributed greatly to India's cultural landscape. From 180 BC, a series of invasions from Central Asia followed, with the successive establishment in the northern Indian Subcontinent of the Indo-Greek, Indo-Scythian and Indo-Parthian kingdoms, and finally the Kushan Empire. From the 3rd century AD onwards the Gupta dynasty oversaw the period referred to as ancient India's "Golden Age". Gupta dynasty built by emperor Ashoka in the 3rd century BC]] In the south, several dynasties including the Chalukyas, Cheras, Cholas, Kadambas, Pallavas and Pandyas prevailed during different periods. Science, art, literature, mathematics, astronomy, engineering, religion and philosophy flourished under the patronage of these kings. Following the Islamic invasions in the beginning of the second millennium, much of north and central India came to be ruled by the Delhi Sultanate, and later, much of the entire subcontinent by the Mughal dynasty. Nevertheless, several indigenous kingdoms remained or rose to power, especially in the relatively sheltered south. Vijayanagara Empire was notable among such kingdoms. During the middle of the second millennium, several European countries, including the Portuguese, Dutch, French and British, who were initially interested in trade with India, took advantage of fractured kingdoms fighting each other to establish colonies in the country. After a failed insurrection in 1857 against the British East India Company, popularly known in India as the First War of Indian Independence and most commonly known in the West as the Indian Mutiny, most of India came under the direct administrative control of the crown of the British Empire. British Empire, Orissa built in the 13th century, is one of the most famous monuments of stone sculpture in the world.]] sculpture in the 10th century AD.]] In the early part of the 20th century, a prolonged and largely non-violent struggle for independence, the Indian independence movement, followed, to be eventually led by Mahatma Gandhi, regarded officially as the Father Of The Nation. The culmination of this path-breaking struggle was reached on 1947-08-15 when India gained full independence from British rule, later becoming a republic on 1950-01-26. As a multi-ethnic and multi-religious country, India has had its share of sectarian violence and insurgencies in different parts of the country. Nonetheless, it has held itself together as a secular, liberal democracy barring a brief period from 1975 to 1977 during which the then Prime Minister Indira Gandhi declared a "state of emergency" with the suspension of civil rights. India has unresolved border disputes with China, which escalated into a brief war in 1962, and Pakistan which resulted in wars in 1947, 1965, and 1971, and a border altercation in the northern state of Kashmir in 1999. India was a founding member of the Non-Aligned Movement and the United Nations. In 1974, India conducted an underground nuclear test, making it an unofficial member of the "nuclear club", which was followed up with a series of five more tests in 1998. Significant economic reforms beginning in 1991 have transformed India into one of the fastest growing economies in the world and added to its global clout.

Government

The Constitution of India states India to be a sovereign, socialist, secular, democratic republic. India is a federal republic, with a bicameral parliament operating under a Westminster-style parliamentary system. It has a three branch system of governance consisting of the legislature, executive and judiciary. The President, who is the head of state, has a largely ceremonial role. His roles include interpreting the constitution, signing laws into action, and issuing pardons. He is also the Commander-in-Chief of the armed forces. The President and Vice-President are elected indirectly by an electoral college for five-year terms. The Prime Minister is the head of government and most executive powers are vested in this office. He (or she) is elected by legislators of the political party, or coalition, commanding a parliamentary majority, and serves a five-year term incumbent upon enjoying this majority. The constitution does not provide for a post of Deputy Prime Minister, but this option has been exercised from time to time. The legislature of India is the bicameral Parliament which consists of the upper house known as the Rajya Sabha, or Council of States, the lower house known as the Lok Sabha, or House of the People, and the President. The 245-member Rajya Sabha is chosen indirectly through an electoral college and has a staggered six year term. The 545-member Lok Sabha is directly elected for a five year term, and is the determinative constituent of political power and government formation. All Indian citizens above the age of eighteen are eligible to vote. The executive arm consists of the President, Vice-President and the Council of Ministers (the Cabinet) headed by the Prime Minister. Any minister holding a portfolio must be a member of either house of parliament. In India's parliamentary system, the executive is subordinate to the legislature. India's independent judiciary consists of the Supreme Court, headed by the Chief Justice of India. The Supreme Court has both original jurisdiction over disputes between states and the Centre, and appellate jurisdiction over the High Courts of India. There are eighteen appellate High Courts, having jurisdiction over a large state or a group of states. Each of these states has a tiered system of lower courts. A conflict between the legislature and the judiciary is referred to the President.

Politics

Chief Justice of India For most of its independent history, India's national government has been controlled by the Indian National Congress Party. Following its position as the largest political organisation in pre-independence India, Congress, usually led by a member of the Nehru-Gandhi family, dominated national politics for over forty years. In 1977, a united opposition, under the banner of the Janata Party, won the election and formed a non-Congress government for a short period after the unpopular 'emergency rule' imposed by Indira Gandhi in the previous Congress regime. In 1996, the Bharatiya Janata Party (BJP), a political party with a right wing nationalist ideology, became the largest single party, and established for the first time a serious opposition to the largely centre-left Congress. But power was held by two successive coalition governments, who stayed on with the support of the Congress. In 1998, the BJP formed the National Democratic Alliance (NDA) along with smaller parties and became the first non-Congress government to sustain the full five year term after it returned to power in 1999. The decade prior to 1999 was marked by short-lasting governments, with seven separate governments formed within that period. One however, a Congress government formed in 1991, lasted the full five years and initiated significant economic reforms. In the 2004 Indian elections the Congress party returned to power after winning the largest number of seats, by a narrow margin. Congress formed a government in alliance with the Communist Party of India (Marxist) and with several mostly-regional parties called the United Progressive Alliance. The NDA, led by the BJP, currently forms the main opposition. All governments formed since 1996 have required party coalitions, with no single majority party, due to the steady rise of regional parties at the national level.

States and union territories

India is divided into twenty-eight states (which are further subdivided into districts), six Union Territories and the National Capital Territory of Delhi. States have their own elected government, whereas Union Territories are governed by an administrator appointed by the union government, though some have elected governments. India has had two scientific bases in Antarctica – the Dakshin Gangotri and Maitri, but has made no territorial claims so far.

Geography

Maitri in the north to Arunachal Pradesh in the far east making up most of India's eastern borders]] India's entire north and northeast states are made up of the Himalayan Range. The rest of northern, central and eastern India consists of the fertile Indo-Gangetic plain. Towards western India, bordering southeast Pakistan, lies the Thar Desert. The southern Indian peninsula is almost entirely composed of the Deccan plateau. The plateau is flanked by two hilly coastal ranges, the Western Ghats and Eastern Ghats. India is home to several major rivers such as the Ganga (Ganges), the Brahmaputra, the Yamuna, the Godavari, and the Krishna. The rivers are responsible for the fertile plains in northern India which are conducive to farming. The Indian climate varies from a tropical climate in the south to a more temperate climate in the north. Parts of India which lie in the Himalaya have a tundra climate. India gets most of its rains through the monsoons.

Economy

monsoon India has an economy ranked as the tenth largest in the world in terms of currency conversion and fourth largest in terms of purchasing power parity. It recorded one of the fastest annual growth rates of 6.9% for the year ending March 2005. India's per-capita income by purchasing power parity is US$ 3,262, ranked 125th by the World Bank. India's foreign exchange reserves amount to over US$ 143 billion. Mumbai serves as the nation's financial capital and is also home to both the headquarters of the Reserve Bank of India and the pre-eminent Bombay Stock Exchange. While a quarter of Indians still live below the poverty line, a large middle class has now emerged along with the rapid growth of the IT industry. The Indian economy has shed much of its historical dependence on agriculture, which now contributes to less than 25 % of GDP. Other important industries are mining, petroleum, diamond polishing, films, textiles, information technology services, and handicrafts. Most of India's industrial regions are centred around major cities. In recent years, India has emerged as one of the largest players in software and business process outsourcing services, with revenues of US$ 17.2 billion in 2004 to 2005. Many small-scale industries provide steady employment to workers in small towns and villages. business process outsourcing While India receives only around three million foreign visitors a year, tourism is still an important but under-developed source of national income. Tourism contributes 5.3 % of India's GDP. The actual employment generation, both direct and indirect, is estimated to be 42 million, or about 10 % of India's work force. In monetary terms, it contributes about US$4 billion in foreign exchange. India's major trading partners are the United States, Japan, China and the United Arab Emirates. India's main exports items include agricultural products, textile goods, gems and jewellry, software services and technology, engineering goods, chemicals and leather products while its main import commodities are crude oil, machinery, gems, fertiliser, chemicals. For the year 2004, India's total exports stood at US$ 69.18 billion while the imports were worth at US $89.33 billion.

Demographics

India is the second most populous country in the world, with only China having a larger population. By 2030, India is expected to surpass China with the world's largest population, estimated at 1.6 billion. Language, religion, and caste are major determinants of social and political organisation within the highly diverse Indian population today. Its biggest metropolitan agglomerations are Mumbai (formerly Bombay), Delhi, Kolkata (formerly Calcutta) and Chennai (formerly Madras). Chennai]] India's literacy rate is 64.8 % with 53.7 % of females and 75.3 % of males being literate. The sex ratio is 933 females for every 1000 males. Work Participation Rate (WPR) (the percentage of workers to total population) stands at 39.1 % with male WPR at 51.7 % and female WPR at 25.6 % inote|eu{inote|demostats{inote|religion{ref|languages{inote|tongues{see2|Christianity in India|Jews in India{seealso3|List of Indian languages by total speakers|List of cities in India|Religion in India{main|Culture of India{seealso4|List of World Heritage sites in India|Indian architecture|Indian family name|Cuisine of India{main|Sports in India{main|Holidays in India{Official Holidays of India{Topics related to India{portal{sisterlinks|India{wikitravel{wikicities|india|India{explain-inote{Web reference | title=India facts and figures | work=Embassy of India| URL= http://www.indianembassy.org/dydemo/indiaprofile/profile.htm | date=August 14 | year=2005{Web reference | title= Forex reserves up by $1bn | work=Economic Times| URL= http://economictimes.indiatimes.com/articleshow/1093864.cms | date=August 14 | year=2005{Web reference | title= India Economy | work=Travel Document Systems |URL= http://www.traveldocs.com/in/economy.htm | date=August 14 | year=2005{Web reference | title= Services | work=India in Business| URL= http://www.indiainbusiness.nic.in/india-profile/ser-infotech.htm | date=August 14 | year=2005{Web reference | title= Destination India: An Unpolished Diamond | work=Times of India | URL= http://timesfoundation.indiatimes.com/articleshow/819309.cms | date=August 14 | year=2005{Web reference | title= US, UAE, UK, China, Japan among India's top trade partners | work=Indian Express| URL= http://www.indianexpress.com/news/business/20050102-0.html | date=August 14 | year=2005{Web reference | title= CIA Factbook : India | work=CIA Factbook | URL= http://www.cia.gov/cia/publications/factbook/geos/in.html | date=August 14 | year=2005{Web reference | title= Provisional Population Totals 2001 Census| work=Census of India| URL=http://www.censusindia.net/results/resultsmain.html | date=August 14 | year=2005{Web reference | title= Debating India & India's literacy rate | work=Debating India | URL= http://india.eu.org/1963.html | date=August 14 | year=2005{Web reference | title= India – Country profiles | work=indexmundi.com | URL= http://www.indexmundi.com/India/ India | date=August 14 | year=2005{Web reference | title= Census of India 2001, Data on Religion | work=Census of India | URL= http://www.censusindia.net/results/religion_main.html | date=August 14 | year=2005{Web reference | title= Languages of India | work=India image | URL= http://indiaimage.nic.in/languages.htm| date=August 14 | year=2005{Book reference | Author=K.M. Matthew | Title=Manorama Yearbook 2003 | Publisher= Malaya Manorama | Year=2003 | ID=ISBN 8190046187{mnb|afgh|1{mnb|LoC|2{South Asia{Asia{Commonwealth of Nations{SAARC{Life in India{Link FA|sv{Link FA|sv

Spacecraft

, 2004.]] A spacecraft is a vehicle that travels through space. Spacecraft include robotic or unmanned space probes as well as manned vehicles. The term is sometimes also used to describe artificial satellites, which have similar design criteria.

Overview

The term spaceship is generally applied only to spacecraft capable of transporting people. A space suit has at times been called a miniature spacecraft or spaceship, emphasizing its purpose of keeping its wearer alive while traveling in the vacuum of outer space. The spacecraft is one of the primal elements in science fiction. Numerous short stories and novels are built up around various ideas for spacecraft. Some hard science fiction books focus on the technical details of the craft, while others treat the spacecraft as a given and delve little into its actual implementation.

Examples of past or existing spacecraft

Manned
- Apollo Spacecraft
- Gemini Spacecraft
- International Space Station
- Mir
- Mercury Spacecraft
- Shuttle Buran
- Shenzhou Spacecraft
- Space Shuttle
- Soyuz Spacecraft
- SpaceShipOne
- Voskhod Spacecraft
- Vostok Spacecraft Unmanned
- Cassini-Huygens
- Cluster
- Deep Space 1
- Genesis
- Mars Exploration Rover
- Mars Global Surveyor
- Mars Pathfinder
- Pioneer 10
- Pioneer 11
- Progress
- SOHO
- Stardust
- Viking 1
- Viking 2
- Voyager 1
- Voyager 2
- WMAP

Spacecraft under development

- Crew Exploration Vehicle
- Kliper
- Automated Transfer Vehicle
- H-II Transfer Vehicle
- Ansari X Prize (incl. a list of spacecraft in various stages of completion as of 2005) The US Space Command, according to its "Long Range Plan", is currently planning to develop a weaponized spaceship, which has yet to be announced.[http://www.fas.org/spp/military/docops/usspac/]

External links

- [http://science.hq.nasa.gov/missions/phase.html NASA: Space Science Spacecraft Missions]
- [http://www.skyrocket.de/space/ Gunter's Space Page - Complete information on spacecraft]
- [http://www.cinespaceships.net/ Cinespaceships - Database on spaceships in movie]
- ja:宇宙船

Moon

:For other moons in the solar system see natural satellite. For the astrological meaning of the Moon, see Solar system in astrology. For other uses see Moon (disambiguation). The Moon is the planet Earth's only natural satellite. It has no formal name other than "The Moon", although it is occasionally called Luna (Latin for moon), or Selene, to distinguish it from the generic "moon" (natural satellites of other planets are also called moons). Its symbol is a crescent (Unicode: ☾). The terms lunar, selene/seleno-, and cynthion (from the Lunar deities Selene and Cynthia) refer to the Moon (aposelene, selenocentric, pericynthion, etc.). The average distance from the Moon to the Earth is 384,403 kilometers (238,857 miles). The Moon's diameter is 3,476 kilometers (2,160 miles). The first manmade object to land on the Moon was Luna 2 in 1959, the first photographs of the otherwise occluded far side of the Moon were made by Luna 3 that same year, and the first people to land on the Moon came aboard Apollo 11 in 1969.

The two sides

The far side is sometimes called the "dark side". In this case "dark" means "unknown and hidden" and not "lacking light" as percieved by the name; in fact the far side receives (on average) as much sunlight as the near side, but at opposite times. Spacecraft are cut off from direct radio communication with the Earth when on the far side of the Moon. One distinguishing feature of the far side is its almost complete lack of maria (singular: mare), which are the dark albedo features.

Orbit

The Moon makes a complete orbit about once every 28 days. Each hour the Moon moves relative to the stars by an amount roughly equal to its angular diameter, or by about 0.5°. The Moon differs from most satellites of other planets in that its orbit is close to the plane of the ecliptic and not in the Earth's equatorial plane. Several ways to consider a complete orbit are detailed in the table below, but the two most familiar are: the sidereal month being the time it takes to make a complete orbit with respect to the stars, about 27.3 days; and the synodic month being the time it takes to reach the same phase, about 29.5 days. These differ because in the meantime the Earth and Moon have both orbited some distance around the Sun. The gravitational attraction that the Moon exerts on Earth is the cause of tides in the sea. The tidal flow period, but not the phase, is synchronized to the Moon's orbit around Earth. The tidal bulges on Earth, caused by the Moon's gravity, are carried ahead of the apparent position of the Moon by the Earth's rotation, in part because of the friction of the water as it slides over the ocean bottom and into or out of bays and estuaries. As a result, some of the Earth's rotational momentum is gradually being transferred to the Moon's orbital momentum, resulting in the Moon slowly receding from Earth at the rate of approximately 38 mm per year. At the same time the Earth's rotation is gradually slowing, the Earth's day thus lengthens by about 15 µs every year. A more detailed discussion follows in the section titled Earth & Moon. The Moon is in synchronous rotation, meaning that it keeps the same face turned to the Earth at all times. This synchronous rotation is only true on average because the Moon's orbit has definite eccentricity. When the Moon is at its perigee, its rotation is slower than its orbital motion, and this allows us to see up to an extra eight degrees of longitude of its East (right) side. Conversely, when the Moon reaches its apogee, its rotation is faster than its orbital motion and reveals another eight degrees of longitude of its West (left) side. This is called longitudinal libration. Because the lunar orbit is also inclined to the Earth's equator, the Moon seems to oscillate up and down (as a person's head does when nodding) as it moves in celestial latitude (declination). This is called latitudinal libration and reveals the Moon's polar zones over about seven degrees of latitude. Finally, because the Moon is only at about 60 Earth radii distance, an observer at the equator who observes the Moon throughout the night moves by an Earth diameter sideways. This is diurnal libration and reveals about one degree's worth of lunar longitude. Earth and Moon orbit about their barycenter, or common center of mass, which lies about 4700 km from Earth's center (about 3/4 of the way to the surface). Since the barycenter is located below the Earth's surface, Earth's motion is more commonly described as a "wobble". When viewed from Earth's North pole, Earth and Moon rotate counter-clockwise about their axes; the Moon orbits Earth counter-clockwise and Earth orbits the Sun counter-clockwise. It may seem curious that the inclination of the lunar orbit and the tilt of the Moon's axis of rotation are listed as varying considerably. One must be reminded here that the orbital inclination is measured with respect to the primary's equatorial plane (in this case the Earth's), and that the axis of rotation's tilt is measured with respect to the normal to the satellite's orbital plane (the Moon's). For most planetary satellites, but not for the Moon, these conventions model physical reality and the values are therefore stable. The plane of the lunar orbit maintains an inclination of 5.145 396° with respect to the ecliptic (the orbital plane of the Earth), and the lunar axis of rotation maintains an inclination of 1.5424° with respect to the normal to that same plane. The lunar orbital plane precesses quickly (i.e. its intersection with the ecliptic rotates clockwise), in 6793.5 days (18.5996 years), mostly because of the gravitational perturbation induced by the Sun. During that period, the lunar orbital plane thus sees its inclination with respect to the Earth's equator (itself inclined 23.45° to the ecliptic) vary between 23.45° + 5.15° = 28.60° and 23.45° - 5.15° = 18.30°. Simultaneously, the axis of lunar rotation sees its tilt with respect to the Moon's orbital plane vary between 5.15° + 1.54° = 6.69° and 5.15° - 1.54° = 3.60°. Note that the Earth's tilt reacts to this process and itself varies by 0.002 56° on either side of its mean value; this is called nutation. The points where the Moon's orbit crosses the ecliptic are called the "lunar nodes": the North (or ascending) node is where the Moon crosses to the North of the ecliptic; the South (or descending) node where it crosses to the South. Solar eclipses occur when a node coincides with the new Moon; lunar eclipses when a node coincides with the full Moon.

Earth & Moon

The tides on Earth are generated by the Moon's gravitation (see tide and tidal force for a more detailed discussion). There are two tidal bulges, one in the direction of the Moon, and one in the opposite direction (figure 1). The buildup of these bulges and their movement around the earth causes an energy loss due to friction. The energy loss decreases the rotational energy of the Earth. Since the Earth spins faster than the Moon moves around it, the tidal bulges are dragged along with the Earth's surface faster than the Moon moves, and move "in front of the Moon" (figure 2). Because of this, the Earth's gravitational pull on the Moon has a component in the Moon's "forward" direction with respect to its orbit. This component of the gravitational forces between the two bodies acts like a torque on the Earth's rotation, and transfers angular momentum and rotational energy from the Earth's spin to the Moon's orbital movement. angular momentum Because the Moon is accelerated in forward direction, it moves to a higher orbit. As a result, the distance between the Earth and Moon increases, and the Earth's spin slows down (figure 3). Measurements reveal that the Moon's distance to the Earth increases by 38 mm per year (lunar laser ranging experiments with laser reflectors are used to determine this). Atomic clocks also show that the Earth's day lengthens by about 15 µs every year. However, the formation of tidal bulges on Earth is irregular and not directly related to the frictional energy loss which accompanies the tides. For example, continents on Earth may cause an increase in frictional energy losses and hamper the buildup of tidal bulges (figure 4). The energy loss of the Earth's spin (loss of rotational energy of the Earth) is related to both the energy transfer to the Moon, which depends on the geometry of the mass distributions on Earth (causing a gravity component which pulls the Moon forward), and also to frictional losses, which depends on the properties of the material moving around within tides. The transfer of angular momentum to the Moon's orbit, in contrast, depends only on the geometry of the mass distribution. In general, the angular momentum transferred to the Moon will not correspond to an equivalent energy transfer. There will be a surplus or a deficit in the transfer of angular momentum to the Moon, compared to the energy transfer (figure 5). Since both angular momentum and energy are conserved, there must be a mechanism on earth to store a surplus or a deficit of angular momentum. Candidates for this mechanism are the Earth's magnetic field and internal material currents of the Earth (figure 6). The lunar surface is also subjected to tides from earth, and rises and falls by around 10 cm over 27 days. The lunar tides comprise a mobile component, due to the Sun, and a selenographically fixed one, due to Earth (the Moon keeps the same face turned to the Earth, but not to the Sun). The vertical motion of the Earth-induced component comes entirely from the Moon's orbital eccentricity; if the Moon's orbit were perfectly circular, there would be solar tides only. The magnitude of the Moon's tides corresponds to a Love number of 0.0266, and supports the idea of a partially melted zone around its core. Moonquake waves lose energy below 1000 km depth, and this may also show that the deep material is at least partially melted. The Earth’s Love number is 0.3, corresponding to a movement of 0.5 metres per day; for Venus the Love number is also 0.3. (Source: Patrick Moore, The Data Book of Astronomy - June 2003 Updates)

Origin and history

magnetic field The inclination of the Moon's orbit makes it implausible that the Moon formed along with the Earth or was captured later; its origin is the subject of some scientific debate. Early speculation proposed that the Moon broke off from the Earth's crust due to centrifugal force, leaving an ocean basin (presumed to be the Pacific) behind as a scar. This concept requires too great an initial spin of the Earth. Others speculated the Moon formed elsewhere and was captured into its orbit. Two of the other theories include the coformation or condensation theory and the impact theory, which speculates that the Moon formed from the debris that resulted from a collision between the early Earth and a planetesimal. The Coformation or Condensation hypothesis posits that the Earth and the Moon formed together at about the same time from the primordial accretion disk, the Moon forming from material surrounding the coalescing proto-Earth, similar to the way the planets formed around the Sun. Some suggest that this hypothesis fails to adequately explain the depletion of iron in the Moon. Recently, the Giant Impact theory has been considered a more viable scientific theory for the moon's origin than the coformation or condensation theory. The Giant Impact theory holds that the Moon formed from the ejecta resulting from a collision between a semi-molten Earth and a planet-like object the size of Mars, which has been referred to as Theia. The geological epochs of the Moon are defined based on the dating of various significant impact events in the Moon's history. Analysis of craters and Moon rocks show that there was a late heavy bombardment by asteroids around the period 4000 to 3800 million years ago. Tidal forces deformed the once molten Moon into an ellipsoid, with the major axis pointed towards Earth.

Physical characteristics

Composition

More than 4.5 billion years ago, the surface of the Moon was a liquid magma ocean. Scientists think that one component of lunar rocks, KREEP (K-potassium, Rare Earth Elements, and P-phosphorus), represents the last chemical remnant of that magma ocean. KREEP is actually a composite of what scientists term "incompatible elements": those which cannot fit into a crystal structure and thus were left behind, floating to the surface of the magma. For researchers, KREEP is a convenient tracer, useful for reporting the story of the volcanic history of the lunar crust and chronicling the frequency of impacts by comets and other celestial bodies. The lunar crust is composed of a variety of primary elements, including uranium, thorium, potassium, oxygen, silicon, magnesium, iron, titanium, calcium, aluminium and hydrogen. When bombarded by cosmic rays, each element bounces back into space its own radiation, in the form of gamma rays. Some elements, such as uranium, thorium and potassium, are radioactive and emit gamma rays on their own. However, regardless of what causes them, gamma rays for each element are all different from one another — each produces a unique spectral "signature", detectable by a spectrometer. A complete global mapping of the Moon for the abundance of these elements has never been performed. However, some spacecraft have done so for portions of the Moon; Galileo did so when it flew by the Moon in 1992. [http://photojournal.jpl.nasa.gov/catalog/PIA00131] The overall composition of the Moon is believed to be similar to that of the Earth other than a depletion of volatile elements and of iron.

Selenography

1992 photo.]] When observed with earth based telescopes, the moon can be seen to have some 30,000 craters having a diameter of at least 1 kilometers, but close up observation from lunar orbit reveals a multitude of ever smaller craters. Most are hundreds of millions or billions of years old; the lack of atmosphere or weather or recent geological processes ensures that most of them remain permanently preserved. In the lunar terrae, it is indeed impossible to add a crater of any size without obliterating another; this is termed saturation. The largest crater on the Moon, and indeed the largest known crater within the solar system, forms the South Pole-Aitken basin. This crater is located on the far side, near the south pole, and is some 2,240 km in diameter, and 13 km in depth. The dark and relatively featureless lunar plains are called maria, Latin for seas, since they were believed by ancient astronomers to be water-filled seas. They are actually vast ancient basaltic lava flows that filled the basins of large impact craters. The lighter-colored highlands are called terrae. Maria are found almost exclusively on the Lunar nearside, with the Lunar farside having only a few scattered patches. Scientists think that this asymmetry of lunar features was caused by the synchronization between the Moon's rotation and orbit about the Earth. This synchronization exposes the far side of the Moon to more asteroid and meteor impacts than the near, thereby allowing the maria on the near side to remain relatively undisturbed for many hundreds of millennia. Blanketed atop the Moon's crust is a dusty outer rock layer called regolith. Both the crust and regolith are unevenly distributed over the entire Moon. The crust ranges from 60 km (38 mi) on the near side to 100 km (63 mi) on the far side. The regolith varies from 3 to 5 m (10 to 16 ft) in the maria to 10 to 20 m (33 to 66 ft) in the highlands. In 2004, a team led by Dr. Ben Bussey of Johns Hopkins University using images taken by the Clementine mission determined that four mountainous regions on the rim of the 73 km wide Peary crater at the Moon's north pole appeared to remain illuminated for the entire Lunar day. These unnamed "mountains of eternal light" are possible due to the Moon's extremely small axial tilt, which also gives rise to permanent shadow at the bottoms of many polar craters. No similar regions of eternal light exist at the less-mountainous south pole, although the rim of Shackleton crater is illuminated for 80% of the lunar day. Clementine's images were taken during the northern Lunar hemisphere's summer season, and it remains unknown whether these four mountains are shaded at any point during their local winter season.

Presence of water

Over time, comets and meteorites continuously bombard the Moon. Many of these objects are water-rich. Energy from sunlight splits much of this water into its constituent elements hydrogen and oxygen, both of which usually fly off into space immediately. However, it has been hypothesized that significant traces of water remain on the Moon, either on the surface, or embedded within the crust. The results of the Clementine mission suggested that small, frozen pockets of water ice (remnants of water-rich comet impacts) may be embedded unmelted in the permanently shadowed regions of the lunar crust. Although the pockets are thought to be small, the overall amount of water was suggested to be quite significant — 1 km³. Some water molecules, however, may have literally hopped along the surface and gotten trapped inside craters at the lunar poles. Due to the very slight "tilt" of the Moon's axis, only 1.5°, some of these deep craters never receive any light from the Sun — they are permanently shadowed. Clementine has mapped ([http://www.lpi.usra.edu/research/clemen/clemen.html]) craters at the lunar south pole ([http://www.lpi.usra.edu/research/clemen/2polar.gif]) which are shadowed in this way. It is in such craters that scientists expect to find frozen water if it is there at all. If found, water ice could be mined and then split into hydrogen and oxygen by solar panel-equipped electric power stations or a nuclear generator. The presence of usable quantities of water on the Moon would be an important factor in rendering lunar habitation cost-effective, since transporting water (or hydrogen and oxygen) from Earth would be prohibitively expensive. Clementine twisting the shadow due to the fact that cosmic rays are charged particles.]] The equatorial Moon rock collected by Apollo astronauts contained no traces of water. Neither the Lunar Prospector nor more recent surveys, such as those of the Smithsonian Institution, have found direct evidence of lunar water, ice, or water vapor. Lunar Prospector results, however, indicate the presence of hydrogen in the permanently shadowed regions, which could be in the form of water ice.

Magnetic field

Compared to that of Earth, the Moon has a very weak magnetic field. While some of the Moon's magnetism is thought to be intrinsic (such as a strip of the lunar crust called the Rima Sirsalis), collision with other celestial bodies might have imparted some of the Moon's magnetic properties. Indeed, a long-standing question in planetary science is whether an airless solar system body, such as the Moon, can obtain magnetism from impact processes such as comets and asteroids. Magnetic measurements can also supply information about the size and electrical conductivity of the lunar core — evidence that will help scientists better understand the Moon's origins. For instance, if the core contains more magnetic elements (such as iron) than Earth, then the impact theory loses some credibility (although there are alternate explanations for why the lunar core might contain less iron).

Atmosphere

The Moon has a relatively insignificant and tenuous atmosphere. One source of this atmosphere is outgassing — the release of gases, for instance radon, which originate deep within the Moon's interior. Another important source of gases is the solar wind, which is briefly captured by the Moon's gravity.

Eclipses

The angular diameters of the Moon and the Sun as seen from Earth overlap in their variation, so that both total and annular solar eclipses are possible. In a total eclipse, the Moon completely covers the disc of the Sun and the solar corona becomes visible to the naked eye. Since the distance between the Moon and the Earth is very slightly increasing over time, the angular diameter of the Moon is decreasing. This means that several million years ago the Moon always completely covered the Sun on solar eclipses so that no annular eclipses occurred. Likewise, in several million years the Moon will no longer cover the Sun completely and no total eclipses will occur. Eclipses happen only if Sun, Earth and Moon are lined up. Solar eclipses can only occur at new moon; lunar eclipses can only occur at full moon. See also Solar eclipse and Lunar Eclipse.

Observation of the Moon

Lunar Eclipse During the brightest full moons, the Moon can have an apparent magnitude of about −12.6. For comparison, the Sun has an apparent magnitude of −26.8. The Moon appears larger when close to the horizon. This is a purely psychological effect (see Moon illusion). The angular diameter of the Moon from Earth is about one half of one degree. Various lighter and darker colored areas (primarily maria) create the patterns seen by different cultures as the Man in the Moon, the rabbit and the buffalo, amongst others. Craters and mountain chains are also prominent lunar features. From any location on Earth, the highest altitude of the Moon on a day varies between the same limits as the Sun, and depends on season and lunar phase. For example, in winter the Moon is highest in the sky when it is full, and the full moon is highest in winter. The orientation of the Moon's crescent side also depends on the latitude of the observing site. Close to the equator an observer can see a boat Moon. [http://curious.astro.cornell.edu/question.php?number=393] Like the Sun, the Moon can also give rise to an optical effect known as a halo. For more information on how the Moon appears in Earth's sky, see Lunar phase.

Exploration of the Moon

Lunar phase prepares to descend towards the surface of the Moon. NASA photo.]] NASA standing next to boulder at Taurus-Littrow during third EVA (extravehicular activity). NASA photo.]] The first leap in Lunar observation was caused by the invention of the telescope. Especially Galileo Galilei made good use of this new instrument and observed mountains and craters on the Moon's surface. The Cold War-inspired space race between the Soviet Union and the United States of America led to an acceleration. What was the next big step is politically laden. In the US (and the West in general) the landing of the first humans on the moon in 1969 is seen as a culmination, indeed of the space race in general. But from a scientific point of view the first photographs of the until then unseen far side of the moon in 1959 constituted the second leap in Lunar observation. 1959 and Luna missions]] The first man-made object to reach the Moon was the unmanned Soviet probe Luna 2, which made a hard landing on September 14, 1959, at 21:02:24 Z. The far side of the Moon was first photographed on October 7, 1959 by the Soviet probe Luna 3. Luna 9 was the first probe to soft land on the Moon and transmit pictures from the Lunar surface on February 3, 1966. It was proven that a lunar lander would not sink into a thick layer of dust, as had been feared. The first artificial satellite of the Moon was the Soviet probe Luna 10 (launched March 31, 1966). The first robot lunar rover to land on the Moon was the Soviet vessel Lunokhod 1 on November 17 1970 as part of the Lunokhod program. On December 24, 1968 the crew of Apollo 8, Frank Borman, James Lovell, and William Anders became the first human beings to see the far side of the Moon with their own eyes (as opposed to seeing it on a photograph). Humans first landed on the Moon on July 20, 1969. The first man to walk on the lunar surface was Neil Armstrong, commander of the American mission Apollo 11. The last man to stand on the Moon was Eugene Cernan, who as part of the mission Apollo 17 walked on the Moon in December 1972. See also: A full list of lunar astronauts. Moon samples have been brought back to Earth by three Luna missions (nrs. 16, 20, and 24) and the Apollo missions 11 through 17 (minus Apollo 13, which almost ended in a disaster). On January 14 2004, US President George W. Bush called for a plan to return manned missions to the Moon by 2020. NASA's [http://www.nasa.gov/missions/solarsystem/cev.html plan] to accomplish that goal was announced on March 19 2005, and was promptly dubbed Apollo 2.0 by critics. The European Space Agency has plans to launch probes to explore the Moon in the near future, too. European spacecraft Smart 1 was launched September 27, 2003 and entered lunar orbit on November 15 2004. It will survey the lunar environment and create an X-ray map of the Moon. [http://news.bbc.co.uk/2/hi/science/nature/2818551.stm] [http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=36091] The People's Republic of China has expressed ambitious plans for exploring the Moon and is investigating the prospect of lunar mining, specifically looking for the isotope Helium-3 for use as an energy source on Earth [http://space.com/missionlaunches/china_moon_030304.html]. Japan has two planned lunar missions, LUNAR-A and Selene; even a manned lunar base is planned by the Japanese Space Agency (JAXA). India will also try an unmanned orbiting satellite, called Chandrayan. From the mid-1960's to the mid-1970's there were 65 moon landings (with 10 in 1971 alone), but after Luna 24 in 1976 it suddenly stopped. The Soviet Union started focusing on Venus and space stations and the US on Mars and beyond. In 1990 Japan visited the moon with the Hiten spacecraft, becoming the third country to orbit the moon. The spacecraft released the Hagormo probe into lunar orbit, but the transmitter failed rendering the mission scientifically useless.

Human understanding of the Moon

Myth and folk culture

The Moon as muse

The Moon has been the subject of many works of art and literature and the inspiration for countless others.

Astrology

Scientific understanding

A 5,000 year old rock carving at Knowth, Ireland may represent the Moon, which would be the earliest depiction discovered. In many prehistoric and ancient cultures, the Moon was thought to be a deity or other supernatural phenomenon. Among the first in the Western world to offer a scientific explanation for the Moon was the Greek philosopher Anaxagoras, who reasoned that the Sun and Moon were both giant spherical rocks, and that the latter reflected the light of the former. His atheistic view of the heavens was one cause for his imprisonment and eventual exile. By the Middle Ages, before the invention of the telescope, more and more people began to recognize the Moon as a