Vedic Mathematics is a more popular catchphrase than Vedic Astronomy. The adjective Vedic has become associated with anything Sanskrit! The four Vedas, though, are primarily slokas about ritual, prayer, philosophy. But numbers are mentioned, even revered; 28 stars, new and full moon, eclipses seasons, days, periods, years, etc are mentioned. From these we can glean some facts and deduct concepts.
All arts and sciences, of whatever variety
that existed, had their own separate texts. Invariably, older texts or
anthologies were discarded or forgotten over time, because newer compositions
replaced archaic knowledge. Panini’s grammar, for example, made eleven previous
Sanskrit grammars obsolete. Even scripts of written languages underwent this
change, as Brahmi, Kharoshti inscriptions in India and Sumerian Cuneiform and
Egyptian heiroglyphs show us. As an aside: we rarely hear of Sumerian
commercial mathematics or Pharaonic mathematics.
We don’t know what other texts or
anthologies, existed during the Vedic era. Also, the Vedas were transmitted
from one generation to the next entirely orally. If any other books were
written or even transmitted orally, they are mostly lost to us. The Vedas,
alone, because they were considered sacred, were passed on thousands of years
later, unmodified. No Indian astronomer, from Aryabhata in 5th
century to Pathani Chandrasekar in 19th century refers to the Vedas,
as a source of their astronomy or mathematics – they only refer to jyotisha
siddhantas of earlier astronomers. Nevertheless some historical information may
be gleaned from the Vedas.
Remember also, the Vedas are a compilation
of various slokas of rishis – we don’t truly know the period of their
composition. The puranas, and Vedic commentaries, attribute yugas, millions of
years to history. Geology, archaeology, biology, anthropology consider Indian
civilization to be a few thousand years old; how many thousands is subjective.
Since it is least controversial, I call the period before the 5th
century BC as Vedic, without an upper bound.
Divisions
of Day
The concept of solar (savana or divasa),
lunar(tithi), stellar(nakshatra) days co-existed, as we saw earlier. 28
Nakshatras are listed, but Abhijit was dropped, with no loss to astronomy. The
12 zodiac series from Mesha (Aries) to Mina (Pisces) was a later import,
probably from Babylonia.
The day was divided into two major parts: poorvaahna (forenoon) and aparaahna(afternoon). Poorvahna itself divided into two parts, praatha and samgava. Aparaahna into three parts, madhyaahna, aparaahna and saayaahna. Even today, sandhyaavandanam and maadhyaahnam are important Vedic rituals, performed by millions daily.
This five part division was at some point
superceded by a division of the day into thirty muhurtha-s, fifteen each for daytime and nighttime. Today we number
the hours, from 1 to 12 or 1 to 24 (this is an import from Egyptian astronomy!)
But Vedic muhurthas were named, not numbered. Much later, during the 18
Siddhantas era, and naadi-s
supplemented muhurta-s, as we saw in Aryabhata’s sloka. A naadi equals two muhurta-s.
We use numbered tithis : prathama, dvitiya, trithiya, chaturthi,
panchami (first, second, third, fourth, fifth) upto trayaodashi, chaturdashi. But the Vedas had names, not numbers, for
each tithi. In fact the tithi-s had different names for the day versus
nighttime, and different names during the waxing (shukla paksha) versus waning (krishna
paksha) phase. So there were sixty tithi names for a lunar month. Similarly
there were sixty muhurthas. All these are named in Taittreya Brahmana (3.10). A
sample of these names are shown in the accompanying tables.
Divisions
of the Year
Just as the day was divided into parts, the year also divided into days(Dina), months(Maasa), seasons(Rtu), Ayana(half-years).
The months were named Madhu, Madhava, Shukra etc, not the Chaitra, Vaishaka,
series we use today. Each rtu is a season of two months; India experiences six
seasons, not four like Europe. The ayana is the apparent traversal of the Sun
between northern and southern latitudes; uttaraayana
(also called devaayana) is the
traversal from south to north; dakshinaayana
(also called pitraayana) is traversal
from north to south.
Disparity threatened; the months were
lunar; 12 months came to 354 days; but the solar year was eleven days longer.
To resolve this disparity which threw off the calendar, the concept of adhika maasa was introduced. Adhika
means extra. Basically it was a leap month, similar to a leap day.
A five year cycle after which five solar
years and 62 lunar months aligned again, was called a yuga (which means conjunction).
These demonstrate that the concept of time
evolved even during the Vedic period.
When the yuga transformed to a tremendous
period of 4,32,000 years and a chaturyuga ten times as long is unclear; this is
the period the puranas mention. The five year yuga is not even referred to by
astronomers of the Siddhanta or Classical period, except Brahmagupta, who
rejects it, and the entire Vedanga Jyotisha, without explanation. A fine
historical and philosophical anomaly - the very Brahmagupta who is dismissed as
orthodox for rejecting Aryabhata’s alleged heresies, is not himself considered
a heretic for rejecting an entire Vedanga!
The invocatory sloka of Vedanga Jyotisha
mentions all these divisions of the year, saluting Prajapati, the Creator, as one whose limbs are days, seasons,
months etc.
पञ्चसंवत्सरमयं युगाद्यक्षम् प्रजापतिम् ।
दिनर्तोयनमासाङ्गं प्रणम्य शिरसा शुचिः ॥
Pancha-samvatsam-ayam yugaadi-aksham
prajaapatim
Dina-rtu-ayana-maasa-angam praNamya
shirasaa shuchi
Numbers
The Taittiriya Aranyakam 4.69 of the Krishna Yajur Veda has this sloka
सकृते अग्ने नमः । द्विस्ते नमः। त्रिस्ते नमः। दशकृत्वस्ते नमः । शतकृत्वस्ते नमः । आसहस्रकृत्वस्ते नमः ।अपरिमितकृत्वस्ते नमः ।
Sakrte agne namaH. Dvis-te namaH. Tris-te namaH. Dasha-krtvas-te namaH. Shata-krtvas-te namaH. Aa-sahasra-krtvas-te namaH. Aparimita-krtvas-te namaH.
Translation NamaH (salutations) to Agni. NamaH twice. Namah thrice. Ten times namaH. Hundred times namaH. Thousand times namaH. Unlimited times namaH.
The Taittiriya
Samhita 7.2.20 has this sloka
शताय स्वाहा सहस्राय स्वाहा अयुताय स्वाहा नियुताय स्वाहा प्रयुताय स्वाहा अर्बुदाय स्वाहा न्यर्बुदाय स्वाहा समुद्राय स्वाहा…… परार्धाय स्वाहा
Shataaya svaahaa sahasraaya svaahaa ayutaaya svaahaa niyutaaya svaahaa prayutaaya svaahaa arbudaaya svaahaa nyarbudaaya svaahaa samudraaya svaahaa … paraardhaaya svaahaa
Translation Svaahaa to a hundred, thousand, ten thousand, lakh, etc. up to one
trillion.
This prayer or offering follows a series of prayers, to the first twenty natural numbers, odd numbers, even numbers, multiples of four, five, ten, twenty, forty and fifty. The religious significance is not my scope. What they counted a trillion of, is an enigma. But these slokas demonstrate the use and understanding of decimal (base 10) numbers and large numbers.
Note the absence of the familiar laksha (lakh) and koti (crore). By the classical era, new names for some larger numbers emerged. Aryabhata, for example, uses koti for arbuda, and vrndam for samudra.
The fractions paada, shapha, kushTha and kalaa respectively 1/4, 1/8, 1/12 and 1/16 are mentioned in the Vedas, too.
These are all names of numbers only, not mathematical operations or algorithms, which are explained in Vedangas.
Other
stars, planets, constellations
Five planets are mentioned, but only
Brhaspati by name, and Venus as Vena rather than Shukra. The most famous
constellation was Sapta Rishi, (a
section of Ursa Minor), stars in the polar regions, which revolved around Dhruva, the Pole star. There is a
beatiful poem, comparing stars rising after Vrkam(Sirius),
as birds of heaven chasing the wolf.
The brightest star of the southern
hemisphere, suddenly became visible during this era. This star was called Agastya (Canopus) and linked with the
story of rishi who headed south, requesting the growing Vindhyas to stop until
he return. Perhaps the legend captures the period of a tilt in the earth’s
axis, when the night sky at that latitude became on Aryavrata. Another southern
star is called Vishvamitra, and three surrounding stars, Trishanku.
Comets,
Meteors, Eclipses
A prayer in Atharva veda mentions comets (ulkaani) and meteors (dhoomaketu).
Strangely, except for Varahamihira, no classical astronomer mentioned these
objects.
अत्रि: सूर्यस्य दिवि चक्षुर आधत् स्वर्भानोर अप माया अगुक्षत ||
यं वै सूर्यं स्वर्भानुस् तमसा विध्यद आसुर: |
अत्रयस् तं अन्वविन्धन् न हि अन्ये अशक्नुवन् || Rg Veda 5.40.8-9
This sloka refers to the rishi Atri “who set the press stone, revered the Gods, dispelled the illusions of Svarbhanu and restored the Sun’s light”, a reference to a solar eclipse. “Atri and his sons alone could restore the Sun when Svarbhanu had covered him with darkness”, it continues. By the era of the 18 Siddhantas, Indian astronomers understood eclipses, and could predict them. We will come to that after a look at the Vedangas.
References
- Facets of Indian Astronomy, by KV Sarma
- Vedanga Jyotisha, TS Kuppana Sastry, edited by KV Sarma, 1984
- NPTEL Lectures on Indian Mathematics by Profs MD Srinivas, MS Sriram, K Ramasubramanian