Eternal India Encyclopedia

Eternal India

encyclopedia

Ancient Concepts, Sciences & Systems

month was generally inserted after

Ashadha

Shravana

and

called second

Ashadha

Shravana.

Thus every second or third

year contains thirteen months.

The natural means of measuring a year originated from the ex-

perience of periodic recurrence of climatic seasons. Likewise, the

natural means of measuring a day was the period between two con-

secutive sun-rises and that for a month a period between two full-

moons. The return of the Sun to the same position with respect to

the fixed star might have appeared to be much more reliable than the

slow seasonal variation of the length of day light. There appears to

be a constant attempt at adjusting the lunar month with the season.

The

Taittiriya Samhita

(7.2.6) mentions how 11 days ceremony

(

ekadasharatra

) was performed after lunar year of 354 days to

make up with the seasons (

ritus

) i.e. with the sidereal year of

365.25 days. The idea of intercalating a month at regular intervals

of time or of adding 5 or 6 days in one month or more months was

thus developed.

The cyclic concept of time, developed from the idea of

yuga

cycle, is a central feature of Indian astronomy. The

Mahayuga

is a

period at the beginning of which all the planetary bodies are in

conjunction. During the period they all perform integral (whole)

number of revolutions and at the end of the period they are therefore

again in conjunction. In the

Surya-Siddhanta Mahayuga

is divided

into four mundane ages or yugas : the

Krita

or Golden Age, the

Treta

or Silver Age, the

Dvapara

or the Brazen Age and the

Kali

the Iron Age (the current age through which the world is passing).

The duration of these eras is 1,728,000, 1,296,000, 864,000 and

432,000 solar years respectively in the descending order of 4,3,2

and 1. The

Kali Yuga

began in 3102 B.C. A bigger period than a

Mahayuga

is a

Kalpa

which is equal to 1000

Mahayugas

4,320,000,000 solar years.

The length of a cycle was selected in such a way that the

apsides and nodes also have whole numbers of revolutions. The

Mahayuga of 4,320,000 years is such a period. The length of the

solar year as 365 days 6 hrs 12 mins 35.56 secs is such that the

least number of years containing a whole number of civil (solar)

days is 1,080,000. (4X1,080,000 is 4,320,000). The number 108 is

4 times 27, the number of

nakshatras.

According to Aryabhata

Ma-

hayuga

is divided into four equal parts of 1,080,000 years each.

With the invasion of India by Alexander the Great in the 4th

century B.C. and the subsequent Greco-Roman contacts the solar

calendar and the seven-day week were also introduced. In the solar

calendar the months are named after the signs of the zodiac, being

translations of the Greek originals;

Mesa

(Aries),

Vrishabha

(Tau-

rus),

Mithuna

(Gemini),

Karkata

(Cancer),

Simha

(Leo),

Kanya

(Virgo),

Tula

(Libro),

Vrishcika

(Scorpio),

Dhanus

(Sagittarius),

Makara

(Capricomus),

Kumbha

(Aquarius) and

Mina

(Pisces).

The days of the week were named after their presiding planets as

in the Greco-Roman system:

Ravivara

(Sunday),

Somavara

(Mon-

day),

Mangalavara

(Tuesday),

Budhavara

(Wednesday),

Brihas-

pativara

(Thursday),

Shukravara

(Friday) and

Shanivara

(Satur-

day).

Aryabhata occupies the first place among Indian mathemati-

cians and astronomers of antiquity. He heralded the new science of

mathematics-based astronomy. He was born in the 5th century

A.D. in the reign of the Gupta king Buddhagupta and lived at

Pataliputra (modern Patna) in ancient Magadha (Bihar) and wrote

his

Aryabhatiya

there. Magadha in ancient times was a great

centre of learning. The famous university of Nalanda was located

there. There was a special provision for the study of astronomy in

the university.

Aryabhatiya

is the first earliest preserved work dealing with

mathematics and planetary astronomy. Aryabhata came to the

rescue of astronomy which did not have a scientific basis with the

result that people's faith was badly shaken when there was a

divergence between astronomical prediction and observation. Ar-

yabhata reorganised astronomy on a scientific basis furnishing it

with new tools and techniques and more accurate methods of

observation.

It was. generally believed that the earth was the centre of the

universe round which the sun and the other planets moved. But

Aryabhata differed from the other astronomers of the time in saying

that the earth was not stationary but rotated about its own axis.

For the sake of astronomical calculations, however, Aryabhata took

the earth as fixed like the other astronomers did. That the earth

was spherical in shape was well known.

Apart from

Aryabhatiya,

Aryabhata wrote one more work on

astronomy,

Aryabhata-Siddhanta.

Unlike the

Aryabhatiya

in which

the day was measured from one sunrise to the next (

audayika

), the

Aryabhata-Siddhanta

measured the day from midnight to midnight

(ardharatrika):

This system was at the peak of its popularity in the

7th century when it was used in everyday calculations such as those

pertaining to marriage, nativity etc. Brahmagupta (628 AD)

brought out an abridged edition of the work under the title

Kharida-

Khadyaka

("Food Prepared with Sugarcandy"). It is in use even

today in some parts of India.

The ancient Indians were aware of the existence of only the

seven planets (

graha)

of the ancients : Sun (

Surya

), Moon (

Chan-

dra

), Mercury (

Budha

), Venus (

Shukra

), Mars

{Mangold),

Jupiter

(Brihaspati)

and Saturn

{Shani).

To these, two more were added -

Rahu

and

Ketu,

the ascending and descending nodes of the moon -

to formulate their

Rahu-Ketu

theories of eclipses. (The planets

Uranus, Neptune and Pluto not observable by the naked eye came to

be discovered during recent times and were not mentioned in the

Hindu astronomical texts). The lengths of the year were known and

calculated as also the lunar month.

Eclipses were explained and accurately forecast. For nearly

2000 years, priestly astronomers saw eclipses as caused by Rahu

(presumed to be the head of a demon) devouring the Sun or the

Moon. It was Aryabhata who in the 5th century A.D. provided an

explanation for the eclipses in terms of the Sun being obscured by

the Moon and the shadow of the earth obscuring the Moon. Vara-

hamihira explained clearly the cause of a lunar eclipse as being due

to the entry of the Moon into the shadow of the earth. Nevertheless

he preferred to use the Rahu terminology, stating that the ascend-

ing node is Rahu's head while the descending node is Rahu's tail.

Then, as now, religious rituals were observed during eclipses.

Therefore great importance was placed on the accurate forecasting

of eclipses. The astronomer, Parameswara (15th Century A.D.),

observed and even recorded the lunar and solar eclipses which

occurred over a period of 50 years.

Because of their knowledge of mathematics, Indian astrono-

mers made advances on the knowledge of the Greeks and passed

their knowledge, along with that of mathematics, back to Europe

through the Arabs. The Syrian astronomers (7th century) knew of