Hindu units of time

Vedic and Puranic units of time span from the truti (microsecond) to the mahamantavara (311.04 trillion years). Hindu theology considers the creation and destruction of the universe a cyclic process.

Introduction

Old Indian measures are presently used primarily for religious purposes in Hinduism and Jainism. They also are employed in the teachings of Surat Shabda Yoga.

The Hindu cosmological time cycles are described in verses 11–23 of Chapter 1, Surya Siddhanta:^[1]

(Verse 11). That which begins with respirations (prāna) is called real; that which begins with atoms (truti) is unreal. Six respirations make a vinādi, sixty of these a nādi.

(12). And sixty nādis make a sidereal day and night. Of thirty of these sidereal days is composed a month; a civil month (sāvana) consists of as many sunrises.

(13). A lunar month, of as many lunar days (tithi); a solar (sāura) month is determined by the entrance of the sun into a sign of the zodiac; twelve months make a year. This is called a day of the devas or demi-gods.

(14). The day and night of the devas and of the asuras are mutually opposed to one another. Six times sixty of them are a year of the devas, and likewise of the asuras.

(15). Twelve thousand of these divine years are denominated a chaturyuga (chatur=Four; yuga=Ages); of ten thousand times four hundred and thirty-two solar years.

(16) The difference of the krtayuga and the other yugas, as measured by the difference in the number of the feet of Dharma in each, is as follows :

(17). The tenth part of a chaturyuga, multiplied successively by four, three, two, and one, gives the length of the krta and the other yugas: the sixth part of each belongs to its dawn and twilight.

(18). One and seventy chaturyugas make a (manvantara (Patriarchate of one Manu); at its end is a twilight which has the number of years of a krtayuga, and which is a pralaya (catastrophic end of creation).

(19). In a kalpa (æon) are reckoned fourteen such Manus with their respective twilights; at the commencement of the kalpa is a fifteenth dawn, having the length of a krtayuga.

(20). The kalpa, thus composed of a thousand chaturyugas, and which brings about the destruction of all that exists, is a day of Brahma; his night is of the same length.

(21). His extreme age is a hundred, according to this valuation of a day and a night. The half of his life is past; of the remainder, this is the first kalpa.

(22). And of this kalpa, six Manus are past, with their respective twilights; and of the Patriarch Manu son of Vivasvant, twenty-seven chaturyugas are past;

(23). Of the present, the twenty-eighth chaturyuga, the krtayuga is past; from this point,reckoning up the time, one should compute together the whole number.

Time

The Hindu metrics of time (Kālm Vyavahara) can be summarized as below.

Sidereal metrics

a Paramaanus () is the normal interval of blinking in humans, or approximately 4 seconds
a vighati (विघटि) is 6 paramaanus, or approximately 24 seconds
a ghadiya (घटि) is 60 vighatis, or approximately 24 minutes
a muhurta is equal to 2 ghadiyas, or approximately 48 minutes
a nakshatra ahoratram (नक्षत्र अहोरत्रम्) or sidereal day is exactly equal to 30 muhurtas (Note: A day is considered to begin and end at sunrise, not midnight.)

An alternate system described in the Vishnu Purana Time measurement section of the Vishnu Purana Book I Chapter III is as follows:

10 blinks of the eye = 1 Kásht́há
35 Kásht́hás = 1 Kalá
20 Kalás = 1 Muhúrtta
30 Muhúrttas = 1 day (24 hours)
30 days = 1 month
6 months = 1 Ayana
2 Ayanas = 1 year or one day (day + night) of the gods

Small units of time used in the Vedas

a trasarenu is the combination of 6 celestial atoms.
a truti is the time needed to integrate 3 trasarenus, or 1/1687.5th of a second.
a vedha is 100 trutis.
a lava is 3 vedhas.[1]
a nimesha is 3 lavas, or a blink.
a kshanas is 3 nimeshas.
a kashthas is 5 kshanas, or about 8 seconds.
a laghu is 15 kashthas, or about 2 minutes.[2]
15 laghus make one nadika, which is also called a danda. This equals the time before water overflows in a six-pala-weight [fourteen ounce] pot of copper, in which a hole is bored with a gold probe weighing four masha and measuring four fingers long. The pot is then placed on water for calculation.
2 dandas make one muhurta.
6 or 7 muhurtas make one yamah, or 1/4th of a day or night.[3]
4 praharas or 4 yamas are in each day or each night.[4]

Lunar metrics

a tithi (also spelled thithi ) or lunar day is defined as the time it takes for the longitudinal angle between the moon and the sun to increase by 12°. Tithis begin at varying times of day and vary in duration from approximately 19 to approximately 26 hours.
a paksa (also paksha) or lunar fortnight consists of 15 tithis
a masa or lunar month (approximately 29.5 days) is divided into 2 pakshas: the one between new moon and full moon (waxing) is called gaura (bright) or shukla paksha; the one between full moon and new moon (waning) krishna (dark) paksha [5]
a ritu (or season) is 2 masa
an ayanam is 3 rituhs
a year is 2 Aayanas [6]

Tropical metrics

a yaama (याम) is 7½ Ghatis (घटि)
8 yaamas 1 half of the day(either day or night)
an ahoratram is a tropical day (Note: A day is considered to begin and end at sunrise, not midnight.)

Reckoning of time among other entities

Reckoning of time amongst the pitrs (ancestors).

1 human fortnight (14 days) = 1 day of the pitrs
30 days of the pitrs = 1 month of the pitrs = (14 x 30 = 420 human days)
12 months of the pitrs = 1 year of the pitrs = (12 months of pitrs x 420 human days = 5040 human days)
The lifespan of the pitrs is 100 years of the pitrs (= 36,000 pitr days = 504,000 human days)

Reckoning of time amongst the Devas.

1 human year = 1 day of the Devas.
30 days of the Devas = 1 month of the Devas.
12 months of the Devas = 1 year of the Devas = 1 divine year.
The lifespan of the Devas is 100 years of the Devas (= 36,000 human years)

The Vishnu Purana Time measurement section of the Vishnu Purana Book I Chapter III explains the above as follows:

2 Ayanas (six month periods, see above) = 1 human year or 1 day of the devas
4,000 + 400 + 400 = 4,800 divine years = 1 Krita Yuga
3,000 + 300 + 300 = 3,600 divine years = 1 Tretá Yuga
2,000 + 200 + 200 = 2,400 divine years = 1 Dwápara Yuga
1,000 + 100 + 100 = 1,200 divine years = 1 Kali Yuga
12,000 divine year = 4 Yugas = 1 Mahayuga(also called divine yuga)

Reckoning of time for Brahma.

1000 Mahayugas = 1 kalpa = 1 day (day only) of Brahma

(Two kalpas constitute a day and night of Brahma)

30 days of Brahma = 1 month of Brahma (259.2 billion human years)
12 months of Brahma = 1 year of Brahma (3.1104 trillion human years)
50 years of Brahma = 1 Pararddha
2 parardhas = 100 years of Brahma = 1 Para = 1 Mahakalpa (the lifespan of Brahma)(311.04 trillion human years)

One day of Brahma is divided into 10,000 parts called charanas. The charanas are divided as follows:

**The Four Yugas**
4 charanas (1,728,000 solar years)	Satya Yuga
3 charanas(1,296,000 solar years)	Treta Yuga
2 charanas(864,000 solar years)	Dwapar Yuga
1 charanas(432,000 solar years)	Kali Yuga

[7]

The cycle repeats itself so altogether there are 1,000 cycles of mahayugas in one day of Brahma.

One cycle of the above four yugas is one mahayuga (4.32 million solar years)
as is confirmed by the Gita statement "sahasra-yuga paryantam ahar-yad brahmano viduh", meaning, a day of brahma is of 1000 mahayugas. Thus a day of Brahma, kalpa, is of duration: 4.32 billion solar years. Two kalpas constitute a day and night of Brahma
A manvantara consists of 71 mahayugas (306,720,000 solar years). Each Manvantara is ruled by a Manu.
After each manvantara follows one Sandhi Kala of the same duration as a Krita Yuga (1,728,000 = 4 Charana). (It is said that during a Sandhi Kala, the entire earth is submerged in water.)
A kalpa consists of a period of 1,728,000 solar years called Adi Sandhi, followed by 14 manvantaras and Sandhi Kalas.

A day of Brahma equals

(14 times 71 mahayugas) + (15 x 4 Charanas)

= 994 mahayugas + (60 Charanas)

= 994 mahayugas + (6 x 10) Charanas

= 994 mahayugas + 6 mahayugas

= 1,000 mahayugas

Our current date

Currently, 50 years of Brahma have elapsed and we are in the first Day of the 51st year. This Brahma's day, Kalpa, is named as ShvetaVaraha Kalpa. Within this Day, six Manvantaras have already elapsed and we are in the seventh Manavatara, named as - Vaivasvatha Manvantara. Within the Vaivasvatha Manavantara, 27 Mahayugas (4 Yugas together is a Mahayuga), and the Krita, Treta and Dwapara Yugas of the 28th Mahayuga have elapsed. We are in the Kaliyuga of the 28th Mahayuga. This Kaliyuga began in the year 3102 BC in the proleptic Julian Calendar. Since 50 years of Brahma have already elapsed, we are in the second Parardha, also called as Dvithiya Parardha.

The time elapsed since the current Brahma has taken over the task of creation can be calculated as

432000 x 10 x 1000 x 2 = 8.64 Billion Years (2 Kalpa(day and night) )
[8] 8.64 x 10⁹ x 30 x 12 = 3.1104 Trillion Years (1 year of Brahma)
3.1104 x 10¹² x 50 = 155.52 Trillion Years (50 years of Brahma)

(6 x 71 x 4320000 ) + 7 x 1.728 x 10⁶ = 1.973 billion years elapsed in first six Manvataras, and Sandhi Kalas in the current Kalpa
27 x 4320000 = 116.640000 million years elapsed in first 27 Mahayugas of the current Manvantara
1.728 x 10⁶ + 1.296 x 10⁶ + 864000 = 3.888 million years elapsed in current Mahayuga
3102 + 2010 = 5112 years elapsed in current Kaliyuga.

So the total time elapsed since current Brahma is

155.52 x 10¹² + 1.973x10⁹ + 0.00012053302 = 155.52 Trillion Years

The current Kali Yuga began at midnight 17 February / 18 February in 3102 BC in the proleptic Julian calendar.

Notes

^ cf. Burgess.

References

Ebenezer Burgess. "Translation of the Surya-Siddhanta, a text-book of Hindu Astronomy", Journal of the American Oriental Society 6 (1860): 141–498.
Victor J. Katz. A History of Mathematics: An Introduction, 1998.
Dwight William Johnson. Exegesis of Hindu Cosmological Time Cycles, 2003.
Alaska Mark. Surya Siddhanta, Chapter I with Commentary and Illustrations, 2005.

[1] . Burgess.

[1]