Ancient Indian Astronomy
Key Discoveries :

Calculation of Earth’s circumference

First concept about gravity

First concept of relativity

Determining the number of planets in the Solar System

Concept and calculation of solar and lunar eclipses

Determining sidereal day and year , close to the actual one

The earliest concept of a heliocentric model of the solar system
Figure 3: A page from the book
‘Pancha-Sidhanta’ or ‘FivePrinciples’ written in 400-500
AD. [Shows how eclipses are to
be calculated]
Figure 2: A stone etching from Burzahom,
Kashmir. [a hunting scene, with two bright
objects in the sky, preferably the sun and
the moon
Figure 1: Rock art from Chillas, Kashmir.
[Sun god with the disk of the Sun just
behind him.] The division of the disk into
four quadrants is probably indicative of
the four seasons.
Book ARYABHATIYA
- By Astronomer-Mathematician Aryabhatta (476–550 CE)
Key Contribution:
•
Proposed mathematical heliocentric model of solar system[1], mentioned in his
book “Aryabhatia” , chapter “Gola”. Also mentioned that earth spins on its axis.
•
Calculated the circumference of earth equal to 24835 miles, which differs by 66
mi from the actual result, 24901 miles [2].
•
Calculated length of the day as 23 hours, 56 minutes, and 4.1 seconds[3]; the
actual value is 23:56:4.091 hours. Length of sidereal year 365.25858 days; the
actual value is 365.25636 days; error of 3 minutes & 20 seconds over the length
of a year [4].
•
Provided explanation of lunar and solar eclipse . In his book, he mentioned
1,582,237,500 rotations of the Earth equal to 57,753,336 lunar orbits [4].
•
Explained the cause of rising and setting of star and also the concept of relativity
[4] saying the same way that someone in a boat going forward sees an unmoving Figure 4: Astronomer-Mathematician
Aryabhatta; India’s 1st satellite was
[object] going backward, so [someone]on the equator sees the unmoving stars
named after him
going uniformly westward.
•
A great mathematician, proposed the place-value system numbering system,
provided approximation of Pi (correct to 4 decimal), sinusoidal function.
Reference :
1. Translation from K. S. Shukla and K.V. Sarma, K. V. Āryabhaṭīya of Āryabhaṭa,
2. http://www.livemint.com/Sundayapp/8wRiLexg1N2IOXjeK2BKcL/How-Aryabhata-got-the-earths-circumference-right-millenia-a.html
3. Encyclopaedia of the history of science, technology, and medicine in non-western cultures http://www.springer.com/us/book/9781402044250
4. Gola chapter, Book Aryabhatia
Continuation of Aryabhatta’s Concepts
Brahmagupta (598-668 AD) :
Brahmagupta, in the book Brahmasphuta Siddhanta (AD 628), explained heliocentric system of
Aryabhata (AD 476–550) [1] stating that - all heavy things are attracted towards the center of the earth.
Bhaskaracharya (1114-1185 AD) :
6th Sloka from Sidhanta Shiromani, Bhuvanakosa“akrsta saktisca mahi taya yat svastham guru svabhimukham svasaktya akrsyate
tatpatativa bhati same samantat kva patatviyam khe”.
It means every object falls on the ground due to earth’s force of attraction. This force
allows the sun, earth, moon and constellations to stay in the orbit.
Mention of astronomy in Indian mythology:
In a prayer, to the Hindu God ‘Hanuman’ , named as ‘Hanuman-Chalisa’, by
poet Tulsidas, the distance between the earth and sun has been mentioned
as – “Juga X Sahastra X jojan’ =12000 X 1000 X 8 miles = 9,60,00,000 miles,
(near to the actual value) .
Figure 5: Astronomical Influence in
megalithic structures; Sun dial in 13thcentury CE Sun Temple at Konark in
Orissa, India.
References:
1. https://www.cs.mcgill.ca/~rwest/link-suggestion/wpcd_2008-09_augmented/wp/g/Gravitation.htm