Heliocentricity, Aryabhata, and Indian Astronomy (Part II)

It is quite possible that the early astronomers in India and in the Arabic lands observed this effect with naked eyes. In the Indian astrology (oh, such a loaded word!) there are 27 stars. These must refer to the star constellations – as any layperson would quickly count the stars of a night sky and would conclude that there are certainly more than twenty-seven stars visible to the naked eye on any night. Modern astronomical texts put the number of constellations in the northern hemisphere at about 89; in the southern hemisphere, 35 constellations were identified. In the early history of India, the organization of knowledge was much different from what it is today. Today, to most people mathematics, astrology, poetics, astronomy, and physics are all different disciplines with well-defined boundaries. In the olden days, mathematics, poetry, physics, astronomy, and astrology used to exist in a mixed knowledge base, a sort of intellectual potpourri.  

Aryabhata I

Aryabhata (also known as Aryabhata I to distinguish from the later day mathematician Aryabhata II) was born around 475 A.D. at Kusumupura, a short distance from the present day Patna. In his lifetime, Ujjain used to be the seat of science and astronomy, a city six hundred miles away from Patna. Aryabhata10

worked in astronomy, mathematics, and perhaps a bit in physics. In his time the notions of planets, stars, sun, and astronomy were influenced by the concepts expounded in the Hindu religion. Looking from a modern perspective, one may be tempted to brush aside all the earlier concepts of Hindu religion as irrational and unscientific. But we will be startled by the uncanny correctness of some of the earlier beliefs (or concepts?). Here are some glimpses of those ancient thinkers’ insights (Again, we cannot clearly fathom how these conclusions were arrived at, what were the reasonings and what were the original experimental or observational data):

In the fifth century, Indians computed the age of earth as 4.3 billion years. Modern investigations with radioactive lead and argon give the age of earth about 4 billion years. A more accurate estimate puts the number as 4.6 billion years. The Sanskrit word for gravitation is gurutvakarshan – ‘guru’ meaning heavy (heaven). Does it indicate mass? Akarshan means attractiveness. Does it imply that the ancient investigators had a vague concept of “gravitation”? In physics, gravitational force is unique because it is always attractive. On the contrary, in electricity and magnetism both attractive and repulsive forces are observed. Or, consider the expression – “sapta-aswa-ratha-maruudha” for the sun. Is it just an allegorical way of saying that the visible white light is composed of seven colors? Or is it a poetic utterance that burst into expression upon coming across a nascent rainbow in the sky?

Aryabhata published the famous “The Aryabhatiya” in 499 A.D. The work deals with astronomy and spherical trigonometry. He was the first Indian to describe the earth as a sphere with a diameter of 7,980 miles; we now know that the equatorial diameter of earth is 7926.81 miles!

It appears that Aryabhata probably observed with naked eye (as most amateur sky watchers or astronomers do) the planets and stars and carefully recorded their motions. Perhaps, he also had access to instrumental observations and results achieved by earlier astronomers. He described the planetary motion in terms of epicycles and apsides. Almost one thousand years before Copernicus, Aryabhata postulated that the apparent sunset and sunrise are caused by the rotation of the Earth around its axis. Aryabhata also offered explanations of equinoxes (March 21 and September 22) and solstices (June 22 and December 22) due to the tilt of earth as it revolves around the sun. He calculated the Hindu calendar to consist of 365 days, six hours, twelve minutes, and thirty seconds; it is a slight overestimate. In mathematics, his contributions include right angle triangle (60°, 30°, 90°), formula for sine, formulae for square root and cube root. Aryabhata also computed an extremely accurate value for pi (π) as 3.1416. The Indian Space Research Organization (ISRO) named its first satellite as Aryabhata to commemorate this pioneering astronomer’s discoveries. 

Conclusion

Often I wondered whether the high school textbooks in India should have depicted a more accurate account of the original achievements of the earlier Indian scientists. Except a smattering of a few names such Susrita and Aryabhata, most of the science books (as I recall my high school days) completely ignored the stellar achievements of the pioneers. College textbooks (Indian) often appear to be just mirror copies of the western science books reflecting the glories of Kepler, Galileo, and Newton without any rational analysis of the earlier groundwork done by others. At a minimum, an accurate account of the early Indian scientists and mathematicians would inculcate a sense of pride and self respect in the high school students. The western tilted science curriculum coupled with the pernicious English medium (which puts regional language speaking, yet creative students at a disadvantage) produced enormous devastation in the post independent India and robbed much of the originality in the Indian science. One needs to look only at the lack of Indian Nobel laureates in science during 1947 – 2006 (notwithstanding emigrant luminaries like Drs. S. Chandrasekhar and H. G. Khorana). Books on the early mathematicians such as Aryabhata, Bhaskara, and Brahmagupta were written by a number of Indians, particularly authors well versed in Sanskrit and other Indian languages; but such works need to be brought to the level of aspiring high school and college students across all the states, in the vernacular (as well as English). 

References

1. “Conversations with Jean Piaget”, by Jean Claude Bringuier, University of Chicago Press, 1980

2a. “Lost Discoveries”, by Dick Teresi, Simon and Schuster, 2002

2b.

3. “The Act of Creation”, by Arthur Koestler, Macmillan Press, 1964

4. “The History of Physics”, by Isaac Asimov, Walker and Company, New York, 1985

5. “The Ascent of Man” by Jacob Bronowski, Little Brown, 1973

6. “Mechanics”, by J. P. Den Hartog, Dover, New York 1961, p. 307

7. “A Field Guide to the Stars and Planets”, by D. H. Menzel, Houton Miflin Company, Boston, 1964

8. “Stargazing Astronomy with a Telescope”, by Patrick Moore, Barron’s Educational Series Inc., Woodbury, New York, 1985

9. “The Telescope Handbook and Star Atlas”, by Neale E. Howard, Thomas Y. Crowell Company, New York, 1967

10. “Great Scientists”, vol. 1, edited by Frank N. Magill, Grolier Educational Corporation, Danbury, CT, 1989

☨ I completed the first draft of this article in November 2003. Later in 2005 it was published on the on-line magazine of TLCA (Telugu Literary And Cultural Association) of NY-NJ-CT. Copyright 2003, 2005, and 2021 by the author.