Division of time in Hinduism is a major subject. In the Shanti Parva of the Mahabharata it is stated: “Beyond the mind is the Great Intelligence and beyond the latter is the Great Time, beyond Time is the adorable Vishnu to whom belongs the whole world.” In Vana Parva, Krishna is identified with Kala (Time) and Desha (Space). Thus space and time are identical with the Supreme Being or Absolute in Hinduism. Space, time, God are all one and the same thing and not separate entities.
However, space and time divisions are very much relevant in practical life. Therefore, Charaka Samhita (Sutrasthana I/480) says, “There are nine dravyas. It is used to denote the power, which causes activities, changes, etc. Seventh dravya space balances the time.
There are nine kinds of reckonings of time, viz., of brahma, of gods, of manusha, of the pita, saura, savanna, Chandra, nakshatra and barhaspatya.
The cycle of creation, destruction and re-creation goes on eternally. The life of Brahma is one hundred years. After it, “Naimittika Laya” Brahma occurs, which means the yogic sleep of Brahma. There are some divergences, in detailing about the theory of yugas, manvantaras and kalpas.
One day of Brahma is equal to a kalpa. A kalpa is 4, 320,000,000 human years. One human year constitutes a whole day-night (aho ratra) of the gods. A Mahayuga or Chaturyuga consists of 4,320,000 human years (12,000 divine years). One thousand divine Chaturyuga represent one day of Brahma and the same is the extent of the night of Brahma. Seventy one divine Chaturyuga constitute a manvantara, and fourteen manvantaras constitute a kalpa. The present is called Sveta Varaha kalpa.
At the micro-level, kala is divided minutely, Varahamihira in his Brihat Samhita (first half of the 6th century CE) and Prasatapada in his Bhashya on the Vaisesika Sutra, say, “The units of kala in vyavahara (common use) are – kshana, lava, nimesha, kastha, kata, muhurta, yama, ahoratra, ardmasa, masa, rtu, ayana, samvatsara, yuga, manvantara, kalpa, pralaya and mahapralaya.” Puranas also describe the units of time in detail.
Arthashastra of Kautilya mentions the following units of time: truta, lava, nimesha, kastha, kala, nadika, muhurta, and ahoratra. Two trutas make one lava, two lavas make one nimesha, five nimeshas constitute one kastha, thirty kasithas make one kala. One nadika is of forty kalas and one muhurta contains two nadika, thirty muhurtas make on ahoratra. Thus one muhurta is equal to forty-eight minutes, one kasitha is a little more than a second. One thousand trutas constitute one minute, that means about sixteen trutas make one second. Thus the sixteenth part of a second was the normal unit of time in Bharavarsa in the 3rd century BCE.
The term panchanga is well known in the context of time division. The five parts of this panchanga are – tithi, nakshatra, yoga, karana and vara. One kala of the moon is tithi. The stars are named according to the shapes in which they are viewed from the earth. The whole zodiac is divided into 27 nakshatras (birth stars). There are four parts for every nakshatra.
The yogas are conjunctions of planets, nakshatras and rashis etc and they indicate the movements and position of the sun and the moon and the other planets. They are also twenty seven. The var (week-day) is decided according to the Svami Graha of the first hora of the day. There are 24 horas in a day.
There are twelve rashis (signs) in the zodiac. Each extends over two and one-fourth nakshatras. Muhurtas are the auspicious time.