It has been exciting and very satisfying working in Vigyan Prasar (VP) - for nearly a decade! Since science communication and science popularisation were relatively new and emerging areas, when VP was set up, one could think up and experiment with new ideas and do so on a large scale. My simultaneous involvement in NCSTC only added to the enormous potential of VP, because these two organisations could really complement and supplement each other's work and give rise to synergies which could not have been imagined or envisaged.

As I prepare to put in my papers and say goodbye to VP and my colleagues in VP, let me share some parting thoughts with readers ...

What VP has been able to accomplish in a short span of less than a decade is nothing short of spectacular. Even so, we have miles ahead of us to traverse, many more people to reach and many more peaks to conquer. After being set up in 1989 October, it was only during 1994-95 that VP was able to hire its first few full time staff members and start work in right earnest.

It didn't take very long thereafter for VP to institute several active and vibrant programmes which have been carving out niches for themselves in the country. Our publications programmes, with a number of popular science series on different themes- and some one hundred titles in nine different languages - is really developing into a winner. Most of our publications have received appreciative reviews in prominent dailies and periodicals and all of them sell well through our distributors in different states, at book fairs and via sales from our office through direct mail orders.

The VIgyan PRasar Information System (VIPRIS), consisting of, among others, a homepage on the internet updated every day; a fortnightly clippings service on science, technology & environment, drawn from over 150 newspapers and magazines in Hindi & English; India's first online popular science magazine ComCom and a comprehensive site on Ham-radio available on VP homepage; a bilingual monthly newsletter "Dream-2047" in Hindi & English with a popular science section which is making waves all over the country, and a weekly column "World of Science" in the "Employment News" (Hindi, English & Urdu) with a print order of over 500,000.

Vigyan Prasar's programme of audio visual productions has made use of radio and television as media for distribution of its programmes. During special occasions such as those of the appearance of the Comet Hale-Bopp, the two total solar eclipses of 1995 and 1999, the infamous herbal petrol scandal, etc. VP programmes were telecast on DD1 and several satellite channels (like Star Plus, Zee, City Cable network) and on regional DD Kendras. Many of our programmes continue to be shown regularly on the "Gyan Darshan" channel of DD and also as part of the CIET/NCERT educational telecasts. Our video programmes have also been used by ISRO during their experimental project in Madhya Pradesh. We have done joint programmes in the local languages with Akashvani Kendras at Bhopal, Delhi and Guwahati; several more are under discussion. VP has also replicated NCSTC-AIR's long radio serial "Manav Ka Vikas" and made it available on audio cassette-sets in all the sixteen Indian languages.

Vigyan Prasar's programme on developing a dynamic and active network of science clubs all over the country is taking shape. VIPNET now has over 2000 science clubs spread all over the country affiliated with it. "VIPNET News" is a monthly periodical being developed as a forum exclusively devoted to activities of the VIPNET Science Clubs. Programmes are being formulated and developed to ensure that VIPNET Clubs remain active and engaged in fruitful and exciting activities on a continuing basis. This programme has enormous potential and innumerable possibilities. The target of VIPNET is to affiliate some 50,000 active science clubs, at an average rate of some 100 per district.

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Young contemporary of the senior Aryabhata (born in 476 AD), Varahamihira is perhaps the most well-known exponent of Indian astronomy. Though not an originator in astronomy or mathematics, he was a prolific writer and produced several works, big and small, which had a tremendous impact on later astronomers, particularly astrologers. They not only made earlier astronomical works obsolete, several of them remained in use throughout the last fifteen hundred years, and are still used by the flourishing community of astrologers. Some of his works, particularly the Brhajjataka and its abridged version the Laghujataka, can often be seen even with a city pavement astrologer.

Varahamihira's brief "autobiography"

But this is only one aspect of Varaha's lasting contribution. His Pancasiddhantika is the only available source-book for reconstructing the history of pre-Varaha Indian astronomy. His magnum opus, the Brhat-samhita, though basically an astrological work, is a mine of information for contemporary India's geography, flora and fauna, social and economic life, architecture and fine arts, religion and polity, learning and literature, astronomical and meteorological knowledge, history of science, and a lot about superstitious beliefs and customs. This work, like the Arthasastra of Kautilya, is a valuable asset for the historian of Indian culture, which still remains to be properly reconstructed because of the great paucity of historical literary sources in the country. The traditional Indian Jyotisasastra, treating both astronomy and astrology, is divided into three branches (skandhas) : (1) Tantra or Siddhanta or mathematical astronomy, (2) Hora or horoscopy for weddings (vivaha) and nuptials (jataka) and prognostics (sakuna), for journeys (yatra), and (3) Samhita or mundane astrology. That Varaha composed works in all the three branches is evident from his own statement at the end of his Bahajjataka : "I have composed this Jyotisasangraha in three branches for the benefit of astronomers and astrologers.

Varaha's only known work belonging to the first branch is the Pancasiddhantika, which contains the salient features of earlier five siddhantas known to him. The second branch is covered by his three works : the Brhajjataka, the Brhadvivahapatala and the Brhadyatra. He also composed abridged versions of these works, which usually carry the prefix laghu (small), e.g. Laghujataka and Laghuvivahapatala. The abridged version of Brhadyatra (also Yogayatra) is known as æikanikayatra. Varaha's last and greatest work, the Brhat-samhita, also known as Varahisamhita, comes under the third branch. Its abridged version is known as Samasa-samhita. Several other works have been attributed to him, but their authenticity is doubtful.

OF UJJAYINI

As is the case of many Sanskrit writers of ancient India, we know very little about the personal life of Varahamihira, also known as Varaha and Mihira. According to his own statement in the penultimate verse of his Brhajjataka, "he was a native of Avanti (Western Malawa), the son of sdityadasa and instructed by him, having obtained the blessings of the Sun-god, at Kapitthaka.

He also describes himself as Avantyaka, and his commentator Bhajjataka Utpala styles him svantikacarya.

As for Kapitthaka, manuscripts give different variants. According to Utpala, Kapittha was a village where there was a Sun-temple. It is usually identified with modern Kayatha, a small village about 20 kms from Ujjain on the Ujjain-Maski Road. Recent excavation has shown that the site is an ancient one. From all this it is evident that he lived and taught at the famous city of Ujjayini.

There is no doubt that Varaha belonged to a family of Sun-worshippers. His father's name was Adityadasa (servant of the Sun); his own name, Mihira, is derived from Mithra, the Iranian Sun-god. Not only does he pay homage to the Sun in almost all his works, but he himself was regarded as an incarnation of the Sun-god. His son Prthuyasas, also an astronomer, invokes the Sun-god in the opening verse of his Satpancasika.

MAGA ANCESTRY

The cult of Sun-worship was reintroduced in India in the early centuries of the Christian era and the priesthood was a monopoly of the Maga or Sakadvipi brahmanas, who were Iranians (Sun-worshipping Magi priests) or Scythians settled in India. The story of the importation of the Iranian form of the Sun-worship is described in several PuraSas. From the Kusana period we find in Surrya icons such alien features as close-fitting waist coat and Central Asian high boots. Varaha himself lays down that the proper persons to instal a S™rya image were the Magas. He also instructs that the Sun should be attired in the Northerner's dress (udiccavesa).

An attempt has also been made to trace the name Varahamihira to Iranian "Varaza" and "Mihr". In the Avesta, the Sun-god Mihr is closely associated with Verethraghna (Iranian counterpart of Indra or Vrtraghna), who marched ahead of Mihr in the form of a boar (Varaza). Though the Maga priests were completely assimilated in the brahmanical fold by the time of Varahamihira, his name indicates that the memory of their Iranian origin was still retained. It is difficult to say which original land or tribe Varahamihira's ancestors belonged to, but it is certain that he was a Maga brahmana - that is, a descendent of one of those Persian Zoroastrians who entered India toward the beginning of the Christian era.

For the date of Varahamihira we only have inferential evidence. A popular verse occurring in the Jyotirvidabharana, which is supposed to be a work of the great Kalidasa but is in fact a late forgery, places Varahamihira in the rank of Dhanvantari, Amarasimha, Kalidasa etc., as one of the nine gems of the court of the legendary Vikramaditya who is said to have founded the Vikrama era in 57 BC. This tradition cannot be believed because Varaha in his Pancasiddhantika refers to A, who was born in 476 AD and wrote his Aryabhatiya in 499 AD or a little later. On the other hand, the first author to demonstrate knowledge of the Pancasiddhantika is Brahmagupta in his Brahmasphu˜asiddhanta, which was written at Bhillamala (modern Bhinamala, Rajastan) in 628 AD. This narrows down Varahamihira's lifetime between 499 AD and 628 AD.

The Pancasiddhantika refers to 505 AD as the epoch of Romaka-siddhanta, one of the five siddhantas described by Varaha. Some scholars also regard 505 AD as the year of birth of the author and some others as the year of composition of the Pancasiddhantika. Al-Burani (1030 AD) also says that the work was written in 505 AD. So, Varaha can safely be regarded as younger contemporary of Aryabhata I. According to a tenth century astronomical work (a commentary on the Khanda-Khadya of Brahmagupta by smaraja), Varahamihira died in 587 AD. Whatever the truth, one thing is clear : Varaha's productive period was the first half of the sixth century AD. Varaha's works indicate that he was patronized by some powerful monarch. Opinions vary on the identification of that ruler. According to Dr. Bhau Daji, Varahamihira flourished at the court of Harsa-Vikramaditya, at Ujjayini, in the sixth century AD.

It has also been suggested that he was connected with the Aulikara court at Dasapura (modern Mandasor), and in particular with Yasodhara who is known to have been ruling in 532 AD. Varaha's Brhat- samhita, as noted earlier, contains minute details about different regions of India of his time, which shows that he must have travelled extensively.

There is also the possibility that he might have visited Persia and Ionia or Yavanapura (Alexandria). Varaha's works show that he had thorough knowledge of Greek astronomy and astrology, which was well-known in India and had already influenced Indian astronomy. An earlier astronomer Garga, and also Varahamihira, refer to the proficiency of the Greeks (Yavanas) in astronomy : "The Greeks (Yavanas) are impure (mlecchas) but amongst them the sciences are duly established ; therefore, even they should be honoured as Rsis. Possibly Varaha also knew Greek language, because we find him using large number of Greek words in Sanskritised form, such as the zodiacal signs Kriya (Mesa), Taburi (Brsabha), Jitum (Mithuna), Leya (Simha) etc. and lipta (minutes), hora (hour, horoscope), jamitra (chord) and so on.

Varahamihira, as noted earlier, was a Maga or sakadvipi brahmana and his ancestors hailed from Eastern Iran. Besides being priests of the Sun-god, the Sakadvipi brahmanas were also devoted to astronomical and astrological studies. Perhaps it was at their hand that the Kaniska era (started in 78 AD) changed its name to raka era. The Sakadvipi brahmanas made a revolutionary change in astronomical studies in India.

PANCASIDDHANTIKA

As the name indicates, the work contains summary of five earlier siddhantas known to Varaha. These are : Poulisa, Romaka, Vasistha, Saura and Paitamaha. These earlier astronomical works are lost but their knowledge is preserved in Varaha's Pancasiddhantika, whose importance is stressed by Dr. Thibout, one of the two editors (the other being Pt. Sudhakara Dvivedi) of the work, in these words : "The Pancasiddhantika thus becomes an invaluable source for any one who wishes to study Hindu astronomy from the only point of view which can claim the attention of the modern scholar, namely the historical one." Neugebauer and Pingree, who prepared a new edition of the same work, observe in their Preface: "Written in the sixth century AD, the Pancasiddhantika of Varahamihira is unquestionably one of the most important sources for the history of Indian astronomy and its relation to its Babylonian and Greek antecedents." Varaha's works (Pancasiddhantika and Brhat-samhita) stand at the centre of a period of Indian astronomy, at the end of which we stand and at the other end the Vedaga Jyotisa (c.1000 BC), the earliest independent tract of Indian astronomy that has come down to us.

There is another set of five siddhantas with the same names but of a later origin, that has come down to us. A comparative study of the two sets clearly indicates that the siddhantas known to Varahamihira are the earliest available records of scientific astronomy of the Indians. Therefore, it will not be out of place to mention briefly the main points of these early siddhantas known to Varahamihira.

As to the merit of these old siddhantas, Varaha says : "The siddhanta made by Paulisa is accurate; near to it stands the siddhanta proclaimed by Romaka; more accurate is the Savitra (Saura, i.e. the surya-siddhanta); the remaining two (Vasistha and Paitamaha) have strayed far away from the truth", that is they do not stand the test of observation (drkpratyaya). The Paitamaha-siddhanta, the most inaccurate one, appears to be the oldest among the five, because its astronomical elements are similar to those of the Vedagaa-Jyotisa. Its Yuga is of five years and epoch 80 AD. This siddhanta shows the state of Indian astronomy as yet unaffected by Greek and other foreign influences.

Brass Image of standing surya

The Vasistha-siddhanta, though rated inaccurate, is more advanced than the Paitamaha-siddhanta. In it we find a fully developed lunar calendar, where the tithi is a chronological unit of calculations. In it we find, for the first time, the subdivision of the ecliptic into 12 rasis, amsas and kalas, so as to work out the lagna (the rising point of the ecliptic) at any particular time. The work deals with the motion of five planets known in antiquity and gives the length of the sidereal year as 365.25 days.

The remaining three siddhantas, Romaka, Paulisa and Saura, were more accurate and belonged to a period when, under the influence of Greek astronomy, they were remodelled, retaining the basic fundamentals of ancient Indian astronomy. One important point, common to all the three siddhantas, is the calculation of the ahargana (the number of savana or civil days that have elapsed) from a given epoch. The Pauliwsa-siddhanta was based on a Greek source. The Romaka-siddhanta, which employs the luni-solar method and the Metonic cycle of 19 years, is completely based on Greek astronomy transmitted to India in the early centuries of the Christian era. In the Romaka-siddhanta the ahargaSa is calculated from the epoch - sunset at Yavanapura (Alexandria) on 21 March 505 AD. According to Varaha, Latadeva was the commentator of these two siddhantas based on Hellenistic astronomy.

Varaha mentions the Suryaa-siddhanta (SS) as the most accurate one. In it we find the Mahayuga cycle and the epicycle model for calculating the true (spasta) planetary positions, as well as their true motions. For finding the true positions of the Sun and the Moon, the SS introduces the calculations of Kendra (anomaly), Ksepaka (latitude) and the measurements of the Jya (sines) and Karna (hypotenuse) of the epicycles. The SS was periodically revised by many authors and was highly honoured as a standard astronomical work for centuries. Most of its elements can be found in revised form in the works of Aryabhata(499 AD) and Brahmagupta (628 AD). The work enjoyed great popularity in ancient India. But the old SS, and the other siddhantas summarised by Varaha, are now lost beyond recovery. The available SS and other siddhantas are later compositions. This is why Varaha's Pa¤casiddhantika is the best source for the history of Indian astronomy in the early centuries of the Christian era.

BRHAT-SAMHITA

The Brhat- samhita (BS), composed mainly in Sanskrit poetry, is an encyclopaedic work consisting of about 4000 verses divided into 105 chapters. Dr. Kern's edition of the BS appeared from London in 1864. But a better edition of the work, with the commentary of Utpala or Bhattotpala (966 AD) was prepared by Pt. Sudhakara Dvivedi and was printed in two volumes in 1895-97. Prof. Ramakrishna Bhat has made available a new translation of the BS for the English-knowing.

The commentary of Bhattotpala, probably a native of Kashmir, is of immense help in not only understanding Varaha's BS but also the contributions of many other forgotten astronomers of ancient India. Therefore, there is no exaggeration in saying that Bhattotpala is to Varaha what Mallinatha is to the great Kalidasa. Bhattotpala also commented on Varaha's Brhajjataka and Brahmagupta's Khanda-Khadya. As noted earlier, the BS deals with natural or mundane astrology. The text attests to a high level of sophisticated observation, enquiry and comment, with plenty of material for investigations by historians and scientists alike. In the first two chapters the qualities of a diviner (daivavid) are described. He was required to be "thoroughly conversant with works dealing with calculations of planetary motions, samhita and horoscopy in their details." Varaha decries sham prophets; these were those who made predictions "by sorcery, spirit-possession and learning got by eavesdropping and hearsay".

Next eleven chapters (3-13) deal with motions of planets, comets, star Canopus (Agastya) and the Saptarsis. In the fourteenth chapter, called Kurmavibhaga, the BS apportions various peoples, countries and places to different directions. There are also a number of topographical references scattered throughout the text. Since these data occur in a dated text, their value for historical geography cannot be underestimated. Chapters 21-28 of the BS deal exhaustively with rainfall. "As food forms the very life of living beings, and as food is dependent on rain, this matter should be investigated carefully", observes Varahamihira. Such observations were made and recorded by many ancient Indian authors. The BS abounds in references to the views of Garga, Parasara, Kasyapa, Asita-Devala and others bearing on rainfall. The Krsii-Parasara (c.1000 AD), a work on agriculture and related matters, devotes considerable space to prediction about rainfall, its measurement etc. Many maxims and proverbs, such as those of Ghagha, Bhaddari and Khanadevi, current amongst the agriculturists at present have their roots in the observations made by Indians centuries ago.
 

In the next nine chapters (29-38) we find the description of such phenomena as earthquake, meteors, rainbow etc., and also information about horticulture and agriculture. Connected with agriculture is horticulture which is elaborately dealt with in an exclusive section called Vrksayurvedadyaya (54). This section discusses the preparation of the soil, manuring, propagation, irrigation, distance to be maintained between trees, trees suitable to different kinds of soil, treatment of diseased plants and so on. Besides propagation by sowing, cutting and transplantation, Varaha is aware of the method of grafting also. The section also describes different varieties of plant species.

Chapters 53 and 55-57 of the BS deal with architecture and iconography, and, therefore, provide valuable material for the students of Indian culture. Varaha has discussed several types of residential buildings (he uses the word vastu strictly in the sense of a residential building) and twenty types of temples. Here it will be interesting to note that the word mandira, which is so much popular now-a-days, does not occur in the BS; but according to Utpala it denoted a residential building and not a temple.

Further chapters of the BS deal with such important topics as exploration of subterranean water-springs (53), fauna (60-66), cosmetics and perfumery (76), pregnancy (77) and the fashioning of furniture. The art of exploring underground currents of water goes back to antiquity. Varaha in a chapter called Dakargala (daka = water, argala = wooden stick) has dealt ground water exploration employing termite mounds as a hydrological indicators to locate sources of water occurring at varying depths in different eco-systems. In many cases the BS is the only ancient Indian text to deal with certain subjects. For example, it contains the very first treatment of Gandhayukti, i.e. chemical blending of different perfumery articles in order to create different varieties of perfumes. Similar is the case with the science of gemmology called Ratnapariksa. The BS is the first text that offers a detailed discussion on this subject in four chapters (79-82). At the beginning of this discussion, Varaha enumerates 21 varieties of gems. But of these, he discusses only four in detail : diamond (vajramani), pearl (mukta), ruby (padmaraga) and emerald (marakata). Equally important for the history of science and technology is the material on weights and measures, literature on Jyotisa, coinage, Jovian cycles etc. Rest of the chapters deal with prognostics (sakunas) and other purely astrological matters.

Though an ardent advocate of astrology, Varaha had many progressive ideas. On the Puranic concept of Rahu and eclipses, he asks : " If this Rahu, who is a big serpent in appearance, actually seizes the Sun or the Moon, why should he not obstruct half of the zodiac that lies between his head and tail ?" He stresses the astronomical fact : "At a lunar eclipse, the Moon enters the shadow of the earth, and, at a solar eclipse, the Moon enters the Sun's disk." Varaha also accepted the fact, true for his time, that the time of the appearance and setting of a comet (ketu) cannot be mathematically calculated. Varaha strongly advocated constant revision of the calendar so as to make it tally with sky observation (drkpratyaya). But it was very unfortunate that, perhaps under pressure from orthodoxy, Varaha vehemently refuted Aryabhata's revolutionary theory of the Earth's rotation.

In the whole of Sanskrit literature, Varaha, perhaps, has the highest praise for women. In an independent chapter called Striprasansadyaya (73), he emphatically states : "Damsels beautify gems and are not at all adorned (made more charming) by lustrous gems. ... Nowhere has the creator designed any gem other than women. For, this gem gives delight to men when it is heard of, seen, touched or even remembered; for its sake are done meritorious deeds, and wealth amassed; and from that alone do men derive worldly pleasures and offspring. Such women are indeed the Goddess of fortune living in mortal bodies. Hence they ought to be honoured always with respect and wealth. ... Please tell me the truth, what great fault is there in women that has not been committed already by men ?" Varaha also alludes to the practice of polygamy and suttee (self-immolation of the wife on the funeral pyre of her husband) prevalent in his time.

If Bhattotpala helped in perpetuating the works of Varaha within the country Al-Biruni (973-1048 AD) , the great Arabic scholar from Central Asia, did the same beyond the borders of India. His great work, the Tarikh al-Hind (account of India), is a mine of information for the study of Indian culture, particularly Indian astronomy. Al-Burini translated into Arabic several astronomical works, including the Brhat-samhita and the Laghu-Jataka of Varahamihira. As is evident from the references in his "India", Al-Biruni had high regards for Varaha's knowledge, but even then, he did not fail to comment on some of Varaha's statements "as the ravings of a madman."

ASTROLOGY

The astrology propounded in Varaha's works is not of Indian origin. Though in the later Vedic works and in the epics we find some references to the "science of portents" and the Naksatradarsas or Daivajnas ( i.e., astrologers - they were included in the list of victims for the Purusamedha sacrifice), it is not highly extolled and codified till the time of Varaha. The first astrological documents come from Mesopotamia of the Chaldean period. Then it was only judicial astrology, concerned with at first with affairs of state. In Egypt the earliest horoscopes are from the reign of Augustus C‘sar (first century BC). The Greeks were greatly influenced by the Mesopotamian astrology, and they were the first to develop it into mundane astrology. This reached India along with the Greek astronomical methods. The scientific elements were Indianised in the Surya-Siddhanta and the Aryabhatiya, and the mundane astrology in the works of Varahamihira. Thus began a new era of Indian "Jyotisa-sastra" which includes scientific astronomy as well as astrological superstitions. This was the odd mixture of good and bad, about which Al-Biruni said : "I can only compare their mathematical and astronomical literature, as far as I know it, to a mixture of pearl shells and sour dates, or of pearls and dung, or of costly crystals and common pebbles. Both kind of things are equal in their eyes, since they cannot raise themselves to the methods of a strictly scientific deduction."( Al-Biruni's India, i. p. 25). And, this is perhaps the main reason why ancient Indian science could not develop into modern science.

Sources

1. The Pancasiddhantika of Varahamihira (2 parts) : Text, translation and commentary by D. Pingree and O. Neugebauer, Kobenhavn, 1970-71.

2. The Brhat-Samhita by Varahamihira with the commentary of Bhattotpala : Edited by Pt. Sudhakara Dvivedi, Benaras, 1895-97.

3. Varahamihira's Brhat-Samhita (2 parts) : Text with English translation by Prof. M. Ramakrishna Bhat, Delhi, 1982.

4. The Brhajjataka of Varahamihira : Text and English translation by Swami Vijnanananda, New Delhi, 1979.

5. Ganaka-Tarangini (Sanskrit) : by Pt. Sudhakara Dvivedi, Benaras, 1933.

6. Alberuni's India : Edited by Edward C. Sachau, Delhi, 1964.

7. Shastri, Ajay Mitra : India as Seen in The Brhat-Samhita by Varahamihira, Delhi, 1969.

8. Diksita, Sankara Balaksna : Bharatiya Jyotisa (Hindi), Lucknow, 1963.

9. Gorakha Prasada : Bharatiya Jyotisa ka Itihasa (Hindi), Lucknow, 1956.

10. Mainkar, T. G. (Ed.) : Writings and Speeches of Dr. Bhau Daji, Mumbai, 1947.

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"My aim is to show that the heavenly machine is not a kind of divine, live being, but a kind of clockwork (and he who believes that a clock has a soul, attributes the maker's glory to the work), insofar as nearly all the manifold motions are caused by a most simple, magnetic and material force, just as all motions of the clock are caused by a simple weight. And I also show how these physical causes are to be given numerical and geometrical expression."

It was Johannes Kepler who first correctly explained planetary motions and he is regarded as the founder of celestial mechanics. To answer the question, why the distance and velocities of the planets were as they were, Kepler expounded that 'there must be a force emanating from the Sun which drives the planets round their orbits. Further he thought that this driving force diminishes as the distance from the Sun increases. This explains why the outer planets move more slowly. Thus Kepler not only attempted to describe the motions of heavenly bodies but also ascribed them a physical cause. Kepler's laws of planetary motion, as Arthur Koestler wrote: "were the first 'natural laws' in the modern sense: precise, verifiable statements about universal relations governing particular phenomena, expressed in mathematical terms. They divorced astronomy from theology, and married astronomy to physics".

It was Kepler's Third law of planetary motion that led Isaac Newton to his law of gravitation. Kepler is also regarded as the founder of modern optics. He was the first to investigate the process of picture formation in a pin-hole camera. He explained the process of vision by refraction within the eye. Optics, one of his major works, included a good approximation of Snell's law, improved refraction tables and discussion of the pinhole camera. His Dioptrics has been called the first work of geometrical optics. Kepler was the first to explain how a telescope works. He was also the first who explained that the tides are caused by the Moon.

Johannes Kepler was born on December 27, 1571 in the township of Weil-der-Stadt in Swabia in southwest Germany between the Black Forest, the Neckar, and the Rhine. His father Henrich Kepler was a mercenary adventurer, who once 'ran the risk of hanging' vanished forever from the sight of his family in 1588. His mother Katherine Kepler nee Guldenmann was an inkeeper's daughter. Katherine was brought up by an aunt who was burnt alive as a witch. Kepler's mother was also tried for witchcraft but narrowly escaped being burnt alive. Kepler defended her mother. She was released after fourteen months of imprisonment.

Kepler's parents neither had the inclination nor the means for his education. However, fortunately for Kepler, his native land had exceptional educational facilities. There was also a system of scholarships and grants for "the children of the poor and faithfull who are of a diligent, Christian and God-Fearing disposition". Thus because of his brilliance Kepler had no problem for his progress from school to seminary and from there to university.

In his elementary school he was taught in Latin. The German vernacular was yet to be considered a worthy medium of expression for scholars. After passing the Elementary Latin School Kepler attended the Theological Seminary. In the seminary he was taught Latin, Greek, theology, Pagan classics, rhetoric and dialectics, mathematics and music.

In the seminary he was quite unpopular among his fellow students. They beat him at every opportunity. He had described his childhood in his memoirs, Johannis Kepleri Astronomi Opera Omnid, a remarkable document of self-analysis, perhaps the most introspective piece of writing of the Renaissance. This was written when Kepler was 26 and he refers himself in the third person and often mixes present tense with past tense. Kepler wrote: "He was constantly on the move, ferreting among the sciences, politics, and private affairs, including the lowest kind; always following someone else, and imitating his thoughts and actions. He is bored with conversation...He tenaciously persecuted wrong-doers...He is malicious and bites people with his sarcasm. He hates people exceedingly, and they avoid him but his masters are fond of him...His recklessness knows no limits ...yet he takes good care of his life...His teachers praised him for his good disposition though morally he was the worst among his contemporaries....He was religious to the point of superstition. As a boy of ten years when he first read Holy scripture...he grieved on account of the impunity of his life, the honour to be a prophet was denied him. When he committed a wrong, he performed an expiatory rite hoping it would save him from punishment: this consisted in reciting his faults in public....In this man there are two opposite tendencies; always to regret any wasted time, and always to waste it willingly...Since his caution with money kept him away from play, he often played by himself. It must be noted that miserliness did not aim at acquiring riches but at removing his fear of poverty-although, perhaps avarice results from an excess of this fear."

In the same document Kepler wrote about himself: "In philosophy he read the text of Aristotle in the original...In theology he started at once on the predestination and fell in with the Lutheran view of the absence of free will.... But later on he opposed it ...Inspired by his view of divine mercy, he did not believe that any notion was destined to damnation... He explored various fields of mathematics as if he were the first man to do so (and made a number of discoveries), which later on he found to have already been discovered. He argued with men of every profession for the profit of his mind... He jealously preserved all his writings and kept any book he could lay hands on with the idea that they might be useful at some time in the future. He was the equal of Crusius (his teacher) in his attention to detail, far inferior to Crusius in industry, but his superior in judgement. Crusius collected facts, he analysed them; Crusius was a hoe, he a wedge..."

At the age of twenty he graduated from the Faculty of Arts at the University of Tuebingen. Then he continued his studies at the Theological Faculty. At this stage it seemed that he was destined to be a priest. However, before he could pass his final examination, he was offered the post of a teacher of mathematics and astronomy in Gratz, the capital of the Austrian province of Styria, a country ruled by a Catholic Hapsburg prince and its predominantly Protestant Estates. Kepler had no real knowledge of either mathematics or astronomy, and he had no plan to become an astronomer. If he had earlier shown interest in Copernicus it was not because of his interest in astronomy but because of mystical implications of the Sun-centred universe. Kepler's first reaction to the offer was not very enthusiastic. Kepler later observed that he was hesitant 'not because I was afraid of the great distance of the place (a fear which I condemn in others), but because of the unexpected and lowly nature of the position, and my scant knowledge in this branch of philosophy'. Though Kepler initially hesitated he finally took up the appointment.

Kepler reached Gratz in April 1594. Besides being the teacher of astronomy he was also the "Mathematicus of the Province". In addition to his teaching activity he was also responsible for publication of an annual calendar of astrological forecasts. As a teacher he proved to be totally unsuccessful. In his second year no student came to attend his class. Kepler himself wrote that his lectures were "tiring or at any rate perplexing and not very intelligible". In his self-analysis Kepler attributed his failure as a teacher to his peculiar kind of memory while he forgot everything that did not interest him he was very good at relating one idea to another. Fortunately for Kepler the director of the school was not alarmed by the absence of students in Kepler's class. They thought if students were not there it was "because the study of mathematics is not every man's affair."

They certified Kepler as "a learned and a fitting magister and professor". They asked Kepler to give some additional lectures on Virgil and rhetoric, "so that he should not be paid for nothing - until the public is prepared to profit from his mathematics too".

Kepler's first book, Mysterium Cosmographicum or the Cosmic Mystery (the full title was a long one) was published in 1596 . In this book Kepler describes his attempts to make centuries old idea that the universe is built around certain symmetrical figures-triangle, square, pentagon etc. fit with the Copernican system. Kepler heard about Copernicus, when he was a student in Tuebingen, from his astronomy teacher Michael Maestlin, who was one of the earliest scholars fully to comprehend and accept the work of Copernicus. Kepler was convinced that the Sun must be at the centre of the universe "for physical or, if you prefer, for metaphysical reasons". From Kepler's writings the following four reasons may be attributed to his belief in the Copernican system.

i. Sun is the symbol of God, the Father.

ii. Sun is the source of light and heat

iii. Sun is the generator of the force which drives the planets in their orbits.

iv. A Sun-centred universe is geometrically simpler to deal with.

However, it appears, his basic desire was to synthesise mysticism and science. In any case it was more mystical than scientific. It was based on false premises. However, it contained the seeds of his future discoveries. This book clearly brought out Kepler's belief in a mathematical harmony underlying the universe. Kepler spent rest of his life in search of this mathematical harmony. After 25 years of publication of his first book Kepler wrote: "The direction of my whole life, of my studies and works, has been determined by this one little book". Further he wrote: "For nearly all the books on astronomy which I have published since then were related to one or the other of the main chapters in this little book and are more thorough expositions or completions of it".

In 1597 Kepler, through a friend, sent his first publication, Cosmic Mystery to Galileo _ "to a mathematician named Galileus Galileus, as he signs himself". Galileo promptly acknowledged the gift. He wrote: "Your book, my learned doctor, which you sent me through Paulus Amberger, I received not a few days but merely a few hours ago; since the same Paulus informed me of his impending return to Germany, I would be ungrateful indeed not to thank you at once: I accept your book gratefully as I regard it as proof having been found worthy of your friendship. So far I have only perused the preface of your work, but from this I gained some notion of its intent and I indeed congratulate myself on having an associate in the study of Truth who is a friend of Truth..."

Further in the same letter while promising to read the book Galileo wrote:"... this I shall do more gladly as I adopted the teaching of Copernicus many years ago, and his point of view enables me to explain many phenomena of nature which certainly remain inexplicable according to the more current hypotheses. I have written (conscripsi) many arguments in support of him and in refutation of the opposite view_which, however, so far I have not dared to bring into public light, frightened by the fate of Copernicus himself, our teacher, who, though he acquired immortal fame with some, is yet to an infinite multitude of others (for such is the number of fools) an object of ridicule and derision. I would certainly dare to publish my reflection at once if more people like you existed; as they don't, I shall refrain from doing so."

Kepler was overjoyed with Galileo's prompt response and he did not miss the earliest opportunity to respond to Galileo. In those days you could send letters only through travellers. Kepler wrote: "Your letter, my most excellent humanist....caused me to rejoice twice: first because it meant the beginning of a friendship with an Italian; secondly because of our agreement on the Copernicus cosmography... I assume that if your time has permitted it, you have by now become better acquainted with my little book, and I ardently desire to know your critical opinion of it; for it is my nature to press all to whom I write for their unvarnished opinion; and believe me, I much prefer even the most acrimonious criticism of a single enlightened man to the unreasoned applause of the common crowd".

"I would have wished, however, that you, possessed of such an excellent mind, took up a different position. With your clever secretive manner underline, by your example, the warning that one should retreat before the ignorance of the world, and should not lightly provoke the fury of the ignorant professors; in this respect you follow Plato and Pythagoras, our true teachers. But considering that, in our era, at first Copernicus himself and after him a multitude of learned mathematicians have set this immense enterprise going so that motion of the earth is no longer a novelty, it would be preferable that we help to push home by our common efforts this already moving carriage to its destination... You could help your comrades who labour under such iniquitous criticism, by giving them the comfort of your agreement and the protection of your authority. For not only your Italians refuse to believe that they are in motion because they do not feel it; here in Germany too, one does not make oneself popular by holding such opinions. But there exists argument, which protect us in the face of these difficulties...Have faith, Galilii, and come forward!"

Galileo did not reply to Kepler's exhortations. In fact after this letter Kepler did not hear from Galileo for the next 12 years. Kepler had endorsed Galileo's views and discoveries. He even persuaded some of Galileo's opponents to consider Galileo's claims more seriously. For many years Galileo's response to Kepler's services to him was complete silence. Galileo finally wrote to Kepler on August 10, 1610: "I have received both your letters, my most learned Kepler. The first, which you have already published, I shall answer in the second edition of my observations. In the meantime, I wish to thank you for being the first, and almost the only, person who completely accepted my assertions, though you had no proof, thanks to your frank and noble mind". Kepler had requested Galileo to send an improved telescope constructed by him. Kepler wrote:... "You have aroused in me a great desire to send me your instrument so that at last I too can enjoy, like yourself, the spectacle of the skies". But Galileo never sent one to Kepler.

In 1600 Kepler met Tycho Brahe at Prague. Kepler had realised that without the immense data of Tycho, the greatest astronomical observer before the invention of the telescope he would not be able to 'erect a wonderful edifice'. Once Kepler wrote: "Let all keep silence and hark to Tycho, who has devoted thirty-five years to his observations... For Tycho alone do I wait; he shall explain to me the order and arrangement of the orbits...Then I hope I shall one day, if God keeps me alive, erect a wonderful edifice". But there was no way of laying hands on Tycho's data as he refused to publish his observations until he had worked out his own theory. One year before he met Tycho, Kepler wrote: "Any single instrument of his cost more than my and my whole family's fortune put together....My opinion of Tycho is this : he is superlatively rich, but he knows not how to make proper use of it, as is the case with most rich people. Therefore, one must try to wrest his riches from him".

Tycho also needed Kepler, of course for different reasons. Tycho thought Kepler with his knowledge in mathematics would prove to be an able assistant. His former assistants of Hveen were not in a hurry to join him in his new observatory at Benatek castle. Tycho wrote to Kepler in December 1599: "You have no doubt already been told that I have been most graciously called here by his Imperial Majesty and that I have been received in the most friendly and benevolent manner."

(Tycho Brahe's observatory, as painted by Heinrich Hansen in 1882 (The original is in the Art Gallery of Frederiksborg Castle, Denmark)

"I wish that you would come here, not forced by the adversity of fate, but rather on your own will and desire for common study. But whatever your reason, you will find in me your friend who will not deny you his advice and help in adversity, and will be ready with his help. But if you come soon we shall perhaps find ways and means so that you and your family shall be better looked after in future."

We may say with certainty that each of them was looking for the other. And each was determined to make use of the other for his own purpose. Finally Tycho and Kepler met face to face on February 4, 1600. Kepler, an amateur astronomer, as he was at the time, was overwhelmed by the wealth and precision of Tycho's observations. He expressed his initial reaction in the following words: "Tycho possesses the best observations, and thus so to speak the material for the building of the new edifice; he also has collaborators and everything he could wish for. He only lacks the architect who would put all this to use according to his own design. For although he has a happy disposition and real architectural skills, he is nevertheless obstructed in his progress by the multitude of the phenomena and by the fact that the truth is deeply hidden in them. Now old age is creeping upon him, enfeebling his spirit and his forces."

Kepler was given the assignment to study the orbit of Mars, 'the most difficult planet. Earlier this was handled by Tycho's senior assistant Longomontanus. Later this proved to be very important decision in the history of astronomy. Though Kepler boasted to solve the problem in eight days he took nearly eight years. What Kepler did not know was that the movements of the Mars had been thoroughly and accurately documented but which did not remotely correspond to anyone's expectation. What we should remember is that Kepler did not have any computing assistance as we take it now for granted. What is more Kepler was working before the invention of logarithm. But Kepler did succeed and the result was his New Astronomy (Astronomia Nova).

In this earth-shattering publication Kepler described two of the three immortal Kepler's laws of planetary motion. The first law summarised the following proposition. The planets travelled not in the perfect circles as proposed by Plato, Aristotle and Ptolemy and which formed the basis of Christian theological conception of the universe but in elliptical path. As we know unlike circle which has one centre an ellipse has two foci. Kepler proposed that the Sun was located at one of the two foci. In summary Kepler's first law states: planets move in elipses with the Sun at one focus.

Kepler's Second Law described the variations of the planet's speed along its orbit. It asserted that the line joining the Sun to a planet (radius vector) sweeps out equal areas in equal times. The Kepler's Third Law which was published in his Warmonices Mundi (1619) states: The squares of the periodic times are to each other an the cubes of the mean distances.

The association between Kepler and Tycho lasted for eighteen months, that is from February 1600 to Tycho's death in October 1601. Out of this Kepler spent eight months in Gratz to settle his personal affairs. The relations between Tycho and Kepler were far from cordial. However, what is important is Kepler could make use of Tycho's data.

After Tycho's death Kepler was appointed as Tycho's successor to the post of Imperial Mathematicus. Kepler lived in Prague as Imperial Mathematicus from 1601 to 1612 to the death of Rudolph II. This period was the most fruitful period of his life.

We should remember, as Kepler had said, "The roads by which men arrive at their insights into celestial matters seem to be almost as worthy of wonder as those matters in themselves."

For further reading

1. Arthur Koestler, The Sleepwalkers, Arkane Books, London, 1989.

2. Carola Banmgordt, Johannes Kepler: Life and Letters, Gollanaz, London 1952.

3. Michael J. Crowe, Modern Theories of the Universe from Herschel to Hubble, Dover, New York, 1994.

1. Johannes Kepler 2. Model of the Universe as given in Mysterium Cosmographicum (1598)

3. Tycho Brahe's observatory, as painted by Heinrich Hansen in 1882 (The original is in the Art Gallery of Frederiksborg Castle, Denmark)

4. The title page of Apologia (1622) by Kepler

5. The 'Pythagorean' or 'Platonic' solids

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