Surya Siddhanta- 2 million years old book on astronomy:

Surya Siddhanta is the first among the traditions or doctrines (siddhanta) in archaeo-astronomy of the Vedic era.

Infact, it is the oldest ever book in world which describes earth as sphere but not flat, gravity being reason for objects falling on earth etc.

This is the knowledge that the Sun god gave to an Asura called Maya in Treta Yuga.
This Maya is father-in-law of Ravana, the villain of first ever epic poem, Ramayana.

Going by calculations of Yugas, first version of SuryaSiddhanta must have been known around 2 million years ago.

However, the present version available is believed to be more than 2500 years old, which still makes it the oldest book on earth in Astronomy.

Brahma

This book covers kinds of time, length of the year of gods and demons, day and night of god Brahma, the elapsed period since creation, how planets move eastwards and sidereal revolution. The lengths of the Earth’s diameter, circumference are also given. Eclipses and color of the eclipsed portion of the moon is mentioned.

This explains the archeo-astronomical basis for the sequence of days of the week named after the Sun, Moon, etc. Musings that there is no above and below and that movement of the starry sphere is left to right for Asuras (demons) makes interesting reading.

Citation of the Surya Siddhanta is also found in the works of Aryabhata.
The work as preserved and edited by Burgess (1860) dates to the Middle Ages.

Utpala, a 10th-century commentator of Varahamihira, quotes six shlokas of the Surya Siddhanta of his day, not one of which is to be found in the text now known as the Surya Siddhanta. The present version was modified by Bhaskaracharya during the Middle Ages.

The present Surya Siddhanta may nevertheless be considered a direct descendant of the text available to Varahamihira (who lived between 505–587 CE).

Jotisha

The Surya Siddhanta is a text on astronomy and time keeping, an idea that appears much earlier as the field Jotisha(vedanga) of the Vedic period. The field of Jyotisha deals with ascertaining time, particularly forecasting auspicious day and time for Vedic ritualal. Max Muller, quoting passages by Garga and others for Vedic astrology, states that the ancient Vedic texts describe four measures of time – savana, solar, lunar and sidereal, as well as twenty seven constellations using Taras (stars). According to mathematician and classicist David Pangriee, in the Hindu text Atharvaveda (~1000 BCE) the idea already appears of twenty eight constellations and movement of astronomical bodies. Scholars have speculated that this may have entered India from Mesopotamia(Iraq). According to Pingree, this hypothesis has not been proven because no cunieform tablet or evidence from Mesopotamian antiquity has yet been deciphered that even presents this theory or calculations.

According to Pingree, the influence may have flowed the other way initially, then flowed into India after the arrival of Darius and the Archameniad conquest of Indus valley about 500 BCE. The mathematics and devices for time keeping mentioned in these ancient Sanskrit texts, proposes Pingree, such as the water clock may also have thereafter arrived in India from Mesopotamia.

Yukio Ohashi

However, Yukio Ohashi considers this proposal as incorrect suggesting instead that the Vedic timekeeping efforts, for forecasting appropriate time for rituals, must have begun much earlier and the influence may have flowed from India to Mesopotamia. Ohashi states that it is incorrect to assume that the number of civil days in a year equal 365 in both Indian and Egyptian–Persian year. Further, adds Ohashi, the Mesopotamian formula is different than Indian formula for calculating time, each can only work for their respective latitude, and either would make major errors in predicting time and calendar in the other region.

Kim Plofker states that while a flow of timekeeping ideas from either side. Is plausible, each may have instead developed independently. Because the loan-words typically seen when ideas migrate are missing. On both sides as far as words for various time intervals and techniques.

 

Greek influence

It is hypothesized that contacts between the ancient Indian scholarly tradition and Hellenistic Greece via the Indo-Greek Kingdom. After the Indian campaign with Alexander the great. Specifically regarding the work of Hippocampus (2nd-century BCE), explain some similarities between SuryaSiddhanta and Greek mythology in the Hellenistic situation. For example, SuryaSiddhanta provides table of sines. Function which parallel the Hipparchian table of chords, though the Indian calculations are more accurate and detailed. According to Alan Cromer, the knowledge exchange with the Greeks may have occurred by about 100 BCE. According to Alan Cromer, the Greek influence probably arrived in India by about 100 BCE. The Indians adopted the Hipparchus system. According to Cromer, and it remained that simpler system rather than those made by Ptolemy in the 2nd century.

 

Planetary Diameters in Surya Siddhanta

Surya Siddhanta also estimates the diameters of the planets. The estimate for the diameter of Mercury is 3,008 miles. An error of less than 1% from the currently accepted diameter of 3,032 miles.

It also estimates the diameter of Saturn as 73,882 miles. Which again has an error of less than 1% from the currently accepted diameter of 74,580.

Its estimate for the diameter of Mars is 3,772 miles. Which has an error within 11% of the currently accepted diameter of 4,218 miles.

It also estimated the diameter of Venus as 4,011 miles and Jupiter. As 41,624 miles, which are roughly half the currently accepted values, 7,523 miles and 88,748 miles, respectively.

Trigonometry in Surya Siddhanta

Surya Siddhanta contains the roots of modern trigonometry. It uses sine (jya), cosine (kojya or “perpendicular sine”). And inverse sine (otkramjya) for the first time, and also contains the earliest use of the tangent. And secant when discussing the shadow cast by a gnomon in verses.

Of [the sun’s meridian zenith distance] find the jya (“base sine”) and kojya (cosine or “perpendicular sine”). If then the jya and radius be multiplied respectively by the measure of the gnomon in digits. And divided by the kojya, the results are the shadow and hypotenuse at mid-day.

The ancient civilizations were excellent astronomers. Keep following us. We will be back.