Archive for August, 2009

The wrong Bose at Como

Posted in Blogs (Articles) on August 28th, 2009 by Rajesh Kochhar – Be the first to comment

Economic Times 31May 1994

Rajesh Kochhar

The 70th birthday celebration of the noted physicist Satyendra Nath Bose (1894-1974) in Calcutta was witness to an unusual event. One of the invited speakers in the function was Debendra Mohan Bose (1885-1975) the nephew of the famed Sir Jagadis Chandra Bose (1858-1937) and a well known physicist. He was the grand old man of Calcutta science. In the course of his speech he referred to the 1927 international conference at Como in Italy which he had attended when S N Bose interrupted him by pointing out that D M Bose had gone on an invitation that was actually meant for him. The interrupted by the mild-mannered and usually reticent Satyen Bose caused a flutter, especially because the reference was to a 37-year old incident.

In the year of S N Bose’s birth centenary it is of historical interest to recount what led to this confusion. At the time of the Como conference, S N Bose was a professor at Dacca University where he had moved in 1921. He wrote his famous paper on ‘Planck’s constant. ‘The Como conference, held during 11-20 September 1927, had been billed as a ‘meeting of exceptional interest’ in commemoration of the first centenary of the death of Volta. At this international congress of physics, 14 countries were represented by about 60 invited participant, including 11 Noble laureates. India was represented by two scientists: D M Bose and M N Saha. But, it turned out at the meeting that the organizers had intended to invite S N Bose, the co-founder of Bose-Einstein statistics.

When S N Bose wrote his paper providing statistical mechanical basis for Planck’s radiation law, he very boldly decided to send is to Albert Einstein. In the covering letter dated 4 June 1924, Bose requested Einstein to evaluate his paper, and if found worthy, arrange for its translation into German and publication in the Zeitschrift fuer Physik. Einstein promptly acknowledged Bose’s latter, translated the paper himself, and sent it to the journal with a laudatory note at the end. The paper was received by the journal on 2 July 1924 and published in the August issue.

Einstein remarked in his note that “The method used here gives also the quantum theory of an ideal gas, as I shall show else where” and Einstein’s paper ‘Quantum theory of monatomic ideal gas’ appeared in print on 20 September 1924. Bose’s epoch making work and Einstein’s prompt follow-up gave rise to Bose-Einstein statistics (now shortened to Bose statistics) which applies to elementary particles that are indistinguishable from each other and these, in turn, are termed bosons. Unwittingly, Einstein applied the ‘indistinguishability principle of bosons to the two Boses themselves: S N Bose who corresponded with him and D M Bose who spent time at Berlin.

Bose’s covering letter to Einstein had been signed as S N Bose. However, the paper sent to the Zeitschrift by Einstein is credited simply to Bose (without initials), Dacca University, India. Einstein compounds the mistake by his carelessness in his own follow-up paper. Here he refers to Bose’s epoch-making work but attributes it to Hrn (Mr) D Bose. So what must have happened is when the Como conference decided to invite S N Bose, they went by Einstein’s paper rather than S N Bose’s own. Accordingly the invitation went to D M Bose who made his appearance at Como.

It is not known in which archive the original invitation exists. It is, however, mildly amusing to note that truth was revealed not by the beneficiary D M Bose, but by the victim S N Bose whose next visit abroad was to occur only 27 years later, in July 1954.

Aryabhata reinstalled

Posted in Blogs (Articles) on August 16th, 2009 by Rajesh Kochhar – 2 Comments

Rajesh Kochhar

Aryabhata (born AD 476) is the founder of Siddhantic astronomy which focused on developing mathematical algorithms for calculating planetary orbits and for predicting lunar and solar eclipses. His concise text, composed in AD 499 and known simply as Aryabhatiyam ( Aryabhata’s), influenced all subsequent work on the subject. From Aryabhata’s time till that of Kepler’s laws, Siddhantic astronomers were probably the only ones in the world who could calculate eclipses with any degree of accuracy.

Very little is known about Aryabhata himself. This is so because of the inherent limitations of the oral tradition. Astronomical texts were composed in terse metrical poetry, which was memorized and transmitted from one generation to the next by word of mouth. What was not considered worth preserving for the moment was lost for ever. It is thus not possible to construct a connected account of ancient astronomy or for that matter of any aspect of ancient India.

Internet has given birth to a flourishing industry of concocting details about Aryabhata and others and giving such details wide currency. By attributing to Aryabhata what he did not do , we would be belittling what he actually did.

Here is some authentic information on Aryabhata arranged in question- and- answer form.

Q1. What do we know about Aryabhata, the person?

A. First note that his name is spelt with a single t and not two. He was born in AD 476 and composed his work Aryabhatiyam in AD 499. This we learn from the book itself. The year of his death is not known.

Aryabhata says that he “ sets forth here the knowledge honoured at Kusumpura”. This has been interpreted to mean that Kusumpura was his work place. It has been identified with Patliputra which in turn has been equated with modern Patna.

This is all what we know about Aryabhata from him. Some additional information comes from his commentators ( e.g. the earliest, Bhaskara I ( AD 629)), who declared that Aryabhata hailed from a place , or district, called As’maka. It has not been possible to identify Asmaka. Legend prevails that Aryabhata hailed from Kerala. There is no basis for this. It is a well known fact that Aryabhata’s work was followed and improved upon in Kerala. Attempts to place Asmaka in Kerala may simply be manifestation of a desire to give physical basis to this intellectual relationship.

Bhaskara I also calls Aryabhata Kulapa. By a long shot this has been interpreted to mean that he was the vice-chancellor of Nalanda University! Kulapa could simply mean founder of a school, which Aryabhata certainly was.

The press coverage of 22 July 2009 total solar eclipse claimed that Aryabhata maintained an observatory at Taregna near Patna. This is an instance of history driven by tourism.

Inter-University Centre for Astronomy and Astrophysics, Pune, has erected a statue of Aryabhata to keep company with Galileo, Newton and Einstein. Bare-chested, stocky Aryabhata wearing a sacred thread is of course a figment of imagination. We have no way whatever of knowing what Aryabhata looked like.

Q2. Did Aryabhata believe in the spin of the earth?

A. He certainly did. But the whole thing should not be blown out of proportion.

We do not sense the spin of the earth under our feet. Instead the whole celestial sphere seems to be going around the earth. This indeed was the prevalent world view. Aryabhata boldly asserted that the earth was not static but spun on its axis.

He was severely criticized for this by friends and foes alike. His own follower Varahamihira died AD 587) believed that the earth was static. The otherwise brilliant mathematician astronomer Brahmagupta ( ) severely castigated Aryabhata for believing in the spin of the earth. Such was the onslaught of mainstream criticism that even followers of Aryabhata’s own school retreated. They rather ineffectually changed a word in the Aryabhatiyam text to argue that Aryabhata indeed considered the earth to be static.

If the scientific tradition had been based on written-down prose rather than on oral metrical poetry, Aryabhata’s reasons why he believed the earth spun would have been on record, and might have been considered convincing by later generations.

While today we give credit to Aryabhata for this, we should keep in mind that we know of Aryabhata’s belief in the spin of the earth not from his work or that of his followers but from the charge sheet maintained against him by his opponents. ( Just as we know about many nationalist heroes from the criminal complaint against them recorded by the colonial government.)

It is noteworthy that only a handful of later Indian astronomers believed that the earth rotated on its axis : Prthudaka (AD 860) and Makkibhatta ( AD 1377). Significantly , a religious text , Skandapurana ( , following Aryabhata, describes the earth as a bhramarika ( spinning top).

It should be borne in mind that belief in spin of the earth or otherwise was not relevant for Siddhantic calculations. Brahmagupta did not believe in in it . But that does not mean that he was any the lesser astronomer. Aryabhata himself , like everybody else, maintained that the sun revolved around the earth. As far as kinematics is concerned it matters not who goes around whom.

Aryabhata believed that the earth was all water south of equator ( Gola 12) and that it expanded in size by one yojana during a day of Brahma and contracted during a night( Gola 8).

As Thoreau put it , “ A man is wise with the wisdom of his age only and ignorant with its ignorance”.

Q3. Did Aryabhata believe in heliocentrism?

A. As discussed above , no , he did not. WE take heliocentrism for granted. In its time, it had profound philosophical implications that went beyond planetary theory.Impact of heliocentrism on human thinking should not be under-estimated.

Q4. Did Aryabhata invent zero?

A. No, zero had been known long before that.

Q5.Is Aryabhata the founder of the eclipse theory?

A. No. He is probably the first one to apply it in India. Such theories were already known in Greece and China