My answer to Can you tell who in the world first proposed that the earth rotated on its axis; not the sun, the moon…
Answer by Vishu Menon:
I received a few gems of historic data in response to this question. Marinus Molenaar mentions the name that possibly first proposed axial rotation of the earth – Herakleides Pontikos (387 – 312 BC). Unfortunately, we do not have any records of his findings. We also do not have the works of Aristarchus (310-230 BC), mentioned by Kaushik Ahmed in response to my question. Aristarchus more positively asserted heliocentric nature of the solar system. Unfortunately, his own work has been lost to humanity. We learn about him from Archimedes, who stated in his book Sand Reckoner:
“His hypotheses are that the fixed stars and the sun remain unmoved, that the earth revolves about the sun on the circumference of a circle, the sun lying in the middle of the orbit, and that the sphere of the fixed stars, situated about the same center as the sun, is so great that the circle in which he supposes the earth to revolve bears such a proportion to the distance of the fixed stars as the center of the sphere bears to its surface.”
Ancient Indian philosophers knew of the difference between the stars and the planets, and did speak of a Universal Egg (Brahamanda) from which the creator and the earth originated, but the truth, if any, in the mythical statement ended there. Aryabhata I( (476–550) proposed a revolving earth, zonal time variation, spherical shape of earth and its circumference and explained solar and lunar eclipses with lucidity and mathematical precision while also postulating trigonometric theories, spherical geometry, quadratic equations, finding of squares and square toots, cubes and cube roots, determinants and other aspects of mathematics,
One should consider Mathematician-Astronomer Aryabhata to be of secular bend of mind; unlike other writers of his time (and even of the present times – not to mention even Indian movie makers), he did not begin his work with a devotional statement to a particular deity like Ganesh, Vishnu or Sarawati. Instead, he dedicated the work to Brahman, the Creator of the Universe, “True God”. Aryabhata’s success rests in the fact that his thoughts were not shackled by the religious beliefs of the time. His detractors among his peers as well as those came after him, like Brahmagupta, opposed him on the ground that his idea of a revolving earth did not agree with the Hindu tradition (smriti); that Earth was a firm thing, a virtual goddess.
Aryabhata’s theory of a revolving earth raised the question of the normally observed inertia of bodies. His critics pointed out that if earth rotated towards the East, everything not firmly fixed on it earth would fly towards West, causing a commotion and making life impossible. This paradox was to be explained away some twelve centuries later by a temperamental genius named Sir Isaac Newton (1643-1727).
Without mentioning gravity and probably without any concept of it, Aryabhata wrote:
Aryabhatiya, Chapter IV (Sphere).
5. Half of the spheres of the Earth, the Planets and the asterisms are darkened by their shadows and half, being turned toward the Sun, is light according to their size.
5. The sphere of the Earth, being quite round, situated in the center of space, in the middle of asterisms, surrounded by the orbits of the planets, consists of water, earth, fir and air.
7. Just as a ball formed by a Kadamba flower is surrounded on all sides by blossoms just so the Earth is surrounded on all sides by all creatures terrestrial and aquatic.
Aryabhata knew that time zones varied across the globe. He wrote:
“The sunrise at Lanka is sunset at Siddhapura, midday at Yavakoti, and midnight at Romaka (Rome). (Chapter Gola, Stanza 13).
Though possibly for chauvinistic reasons, Aryabhata आर्यभट: (meaning Aryan Soldier, not a Brahminical name) is often misspelt by a Brahminical spelling, Aryabhatta. He is presumed to have been born in Patna (ancient Pataliputra). However, Aryabhata invariably used the small near-equatorial island of Lanka (now Sri Lanka) as the reference point for determining the beginning of day, night and the yugas (eras), and for estimating latitude and longitude. It is more likely that he was born in Srilanka or Kerala near Kodungaloor (The name means Hard-stone town) in a place called Kusumapura – Flower city – as he mentions in his treatise. This location would have been more suitable for his observation of the celestial bodies over the Indian Ocean and agrees with the fact that all literary works from the South-Western Coast that emanated till the sixteenth century was in Sanskrit; writing in the vernacular was considered to be a matter of shameful illiteracy. It was low-caste Shudra Thunjath Ramanujan Ezhuthachan (1495-1575), who broke that taboo by writing Adhyatma Ramayanam (Spiritual story of Rama) in Malayalam.
Aryabhata is known to have written two major works: Aryabhatiya, his smaller work with four chapters – introductory, Mathematical, Astronomical and ‘Gola’, meaning the Sphere. The other work, AryaSidhanta, meaning theories of Aryabhata, have been lost to the vagaries of time. He is also said to have written a book logically titled Karanagrantha – the Book of Reasons – of which there is no trace in original. Arabian genius Al Beruni mentions this work, whose translation, Al-nanf is said to be available in Arabic.
Aryabhata lucidly explains why the Sun, Moon and the Stars appear to move while we believe ourselves being stationery: (Aryabhatiya Chapter IV (Sphere)
As mentioned before, Aryabhata faced much opposition to his theory that the earth rotated. The theory found no favour with his peers or his reviewers and critics – largely because it conflicted with the religious beliefs of the time. Brahmagupta (598–665AD) was also a severe (and largely erroneous) critic of his mathematical theorems and explanations. While Aryabhata’s explanations and calculations paved the way to predict Lunar and Solar eclipses and other natural phenomena apart from theoretical aspects of astronomy, it helped future astrologers and diviners of almanacs to use his mathematical equations (written in verse). However, Al Beruni, the Islamic genius who came six centuries later, was ambivalent about Aryabhata’s spinning earth theory.
Aryabhata, as do modern scientists, suggests modelling for calculation purposes. Stanza 22 of the third chapter says:
“ A light wooden sphere should be made, round and of equal weight in every part. By ingenuity one should cause it to revolve so as to keep pace with the progress of time by means of quicksilver, oil or water”
To the common question that arises in the mind of a child when she is told that the earth is a sphere and that there are populated continents on the other side, Aryabhata gives this explanation.
“Heaven and Meru (mountains) are at the centre of the land, Hell and Vadavamukhas (horse-faced ones) are at the centre of the water (ocean). The gods and the dwellers in Hell both think constantly that the others are beneath them.”
(Here gods are the Aryans who were supposed to reside in the upper (Northern) hemisphere in Northern India; the horse-faced ones who were supposed to be living below the equator were the other races. Recall that Hindu epics describe non-Aryans as Monkeys (of Hanuman fame), bears (Jambvas) and Rakshasas or Demons (indigenous people) in their epics. Like during Apartheid the Japanese were elevated to the status of Honorary Whites, some useful ‘Monkeys’ like Hanuman were elevated to the status of demi-gods.
American flat-earth theorists and pastors still argue that the earth could not be spherical; Asians on the other side couldn’t be standing with their heads down.
Aryabhata explains the eclipses in a single verse thus:
“:The moon consists of water, the Sun of fire, the earth is earth, and the Earth’s shadow is dark. The moon obscures the Sun and the great shadow of the Earth obscures the Moon.”
Brahmagupta, who came more than a century after Aryabhata retorted that the story of Rahu (a demon in the shape of a snake) swallowing the celestials was good enough for him. Even today, many Hindus believe that poison emanates from this reptilian attack on the Sun and the Moon and hence all must stay indoors while an eclipse is in progress.
In the 11th stanza of his second chapter titled Reckoning Of Time (Ganitapada), Aryabhata makes a startling statement that was to be proclaimed again by Einstein and the later scientists:
Time, which has no beginning and end, is measured by the movements of the planets and the star systems on the globe.
“Time has no existence independent of the motions of the universe.”
Aryabhata’s small book Aryabhatiya, written in verses for ease of committing to memory is super-charged with a huge amount of wisdom and data far ahead of times in his secular style without naming any god of the time. He did not claim , as most Sanskrit works of the time did in closing, that those who read his treatise will be washed of all sins and would go to heaven. Instead he closed his work with Freudian threat to those who disparage it:
(“Chapter IV Stanzas 49 &50). “By the Grace of God the precious sunken jewel of true knowledge has been rescued by me, by means of the boat of my own knowledge, from the ocean which consists of true and false knowledge. He who disparages this universally true science of astronomy, which formerly was revealed by the self-born, and is now described by me in the Aryabhatiya, loses his good deeds and his long life.
Yet all that Aryabhata wrote does not conform to what we know about the universe today. He still believed that the universe was geocentric; the earth was pegged at the centre of the planets and it was the stars that spun around along with Earth in a game of Ringa-ringa roses. Perhaps this was more in tune with the concept propounded by Philolaus Of Tarentum (470 – c. 385 BC) ten centuries before.
Heliocentrism was to be established eighteen centuries after the death of Aristarchus of Samoa (310-230 BC), rather hesitantly and too late in his life for fear of persecution, by a Catholic cleric – Nicolaus Copernicus (1473 –1543) with whom I proudly share my birthday, 19th February. Soon Galilei (1564-1642) was to follow suit with a telescope that was too modern for his time and hence to be persecuted by the Church with house arrest for the rest of his life.