(based on an article by Shyamasundara Das)

"God created time so that everything wouldn't happen at once." (graffiti, men's room, U of Waterloo)

Mysterious energy
Shrinking time
Time dilation
Krsna's energy
Calculation of time
Four cosmic ages (yugas)

Mysterious energy

Time (kala) is one of the five tattvas (realities) of existence which are the five subjects of the Bhagavad-gita. (The other ones are: isvara - God, jiva - living being, prakrti - material nature, and karma - material activity). It is created by the Lord (SB 7.1.11-12).

In the Bhagavad-gita (BG 11.32) Krsna, the Supreme Personality of Godhead, has stated that He is time and that time is all destructive, and "among subduers I am time". (BG 10.30) That time is Krsna by virtue of being one of His multifarious energies explains, to a great extent, the truly mysterious nature and effects of time. Our perception of time can be dependent on our age, which in itself is caused by time. For example it is a common adage that time flies faster the older you get. That somehow a year shrinks with every passing new year. This perception of shrinking time is prevalent in all cultures. How is it possible for time to shrink or at least to appear to do so?

Shrinking time

For a possible explanation let us consider the following experience that I had as a child growing up in Northern Canada, where the seasonal changes are dramatic. As a boy of four years I recall being amazed when winter came and snow appeared again (as it had done one year previously since time immemorial). It seemed to me that I could remember this white stuff falling out of the sky and piling up all over the place. It had happened, I thought, a long time ago and here it was happening again. As I grew I found that it did indeed occur on a regular basis, a yearly basis, but like every one I noticed that as I grew older the time interval seemed to mysteriously grow shorter even though there were still 365.25 days in the year, none added or subtracted. It occurred to me that the only explanation for this shrinking time was my own previous experience of time. To a child of four years, one year would represent 25% of my total previous experience of time to that date. But now that I am 40 years old, one year represents only 2.5% of my previous total experience of time. This is a dramatic decrease by a factor of 10. By the time I am 80, one year will only represent 1.25% of my previous experience. Thus the longer a person lives the smaller a year becomes in relation to their total previous experience of time in this life.

Time dilation

It has been observed by investigators that the perception of time can be influenced, either shortened or lengthen, because of the effects of certain types of drugs. This is especially true with psychotomimetic drugs such as LSD, Mescaline, and others in this category. The users of these drugs often report that they felt that time seemed to stand still. That a moment seemed like eons. This subjective effect of the drug could cause trauma to a user. One user reported to me that he once became quite anxious because of this time dilation effect. He had gone to the latrine to answer the call of nature, but to him it had felt as if a greatly inordinate length of time had been spent using the facilities (he said it felt like years) and thus he became afraid that his friends and family would consider that he was lost and send the police in search of him (the last people he would want to meet under such conditions would be the constabulary).

To experience radical time dilation and contraction one need not be a drug user. You need only to lay down and sleep. It is common experience that in deep sleep, susupti, a long span of time, say 45 minutes, is perceived as lasting only one or two moments. The opposite is true of svapna, the dreaming state. A man may lay down and take a nap and have a dream in which it seems as if many whole life times have gone by, but on waking he finds that less than five minutes have passed.

It is unclear as to whether these time distortions related to drugs and sleep states are the effects of the drugs and sleep states on our perception of time or whether these are qualities of time which these other states of perception allow us to capture.

Then there is the phenomena of time being relative to the species of life that is experiencing it. For example a solar year of 365 days is experienced differently by a dog, human or demigod. It is commonly understood that one dog year is equivalent to seven human years whereas one human year is equivalent to only one day of the demigods. Thus our existence in relation to the demigods would be comparable to that of microbes in relationship to us. Several generations of microbes will have come and gone in the course of one day for us.

Then there are the higher demigods such as Lord Brahma and his associates. Lord Brahma has a life time of 100 years by his calculation which translate to be 311,040,000,000,000 human years. Thus one second for Lord Brahma is equal to 100,000 years for us. According to astronomical texts such as Surya-siddhanta and the Puranas, in cosmic time it is presently the day after the 50th birthday of Lord Brahma. And it is about 11:40 AM for him on his planet. He will be having lunch in about 20 of his minutes, which would take 120,000,000 years of our time. Definitely mind boggling! There are several instances in the Puranas where it is recounted that a person would be transported from the human worlds to that of a deva such as Brahma. And even though they were only gone for what appeared to be a short length of time by their experience, when they returned millions of years had come and gone.

The Experience of King Kakudmi

The following example from the Bhagavata Purana, illustrates time dilation on Brahmaloka, the planet of Lord Brahma, the demiurge of this universe. This historical incident begins with the mention of a submarine kingdom called Kusasthali. The residents of this kingdom were descendants of the solar dynasty. And though they are considered human, they were endowed with mystic powers, not found in ordinary humans today. The King of Kusasthali, Kakudmi, was able to travel to the world of Brahma and experience Brahma's perception of time:

"O Maharaja Pariksit, subduer of enemies, Revata constructed a kingdom known as Kusasthali in the depths of the ocean. There he lived and ruled such tracts of land as Anarta, etc. He had one hundred very nice sons, of whom the eldest was Kakudmi. Taking his own daughter, Revati, Kakudmi went to Lord Brahma in Brahmaloka, which is transcendental to the three modes of material nature, and inquired about a husband for her. When Kakudmi arrived there, Lord Brahma was engaged in hearing musical performances by the Gandharvas and had not a moment to talk to him. Therefore Kakudmi waited, and at the end of the musical performances he offered his obeisances to Lord Brahma and thus submitted his long standing desire. After hearing his words, Lord Brahma, who is most powerful, laughed loudly and said to Kakudmi, 'O King, all those whom you may have decided within the core of your heart to accept as your son-in-law have passed away in the course of time. Twenty-seven catur-yugas have already passed. Those upon whom you may have already decided are now gone, and so are their sons, grandsons and other descendants. You cannot even hear about their names.' (SB 9.3.28-32)

According to Vedic calculations a catur-yuga is equal to 4,320,000 earth years. Thus twenty-seven such cycles would be equal to 116,640,000. From our previous statement that one second of Brahma was equal to 100,000 earth years we find that Kakudmi had only been waiting for 19 minutes and 26 seconds while Lord Brahma finished listening to the musical performance of the Gandharvas. (We shall discuss the Vedic divisions of time in a later section.)

Contemplating these strange effects of time plus the fact that day by day we get older and eventually will die at the hands of time we begin to appreciate why time has engrossed the minds of philosophers for so long.

As we shall soon see the calculation of time is ultimately based on the astronomical motion of the Sun, Moon and other planets. Just think, it would be difficult to be even aware of the passage of time if it were not for the successive rising and setting of the sun which demarks the night and day of our experience. The daily solar cycle controls when we rise, go to sleep, eat, work, mate, etc.

Studies have been done on subjects who have been isolated from the sun and other atmospheric cycles by being placed deep underground in caves such as the Carlsbad Caverns. These experimental subjects were given no clocks and put on no schedules. There was no routine time of contact. All efforts were made to obliterate any sense of time and cycle caused by the sun or anything else. The subjects contacted the surface with telephones and gave information as to when they would get up, eat, go to sleep, etc. It was found that gradually the sleep-wake cycle in that particular case would dramatically change to being on a 48 hour cycle rather than a 24 hour cycle. This went on for months with major variations in the wake-sleep cycle. This clearly shows how we are closely governed in our normal experience by the rising and setting of the sun. The sun not only gives us our daily cycle but also our seasonal changes leading to the yearly cycle.

Between the day and the year the cycle of the Moon is prominent. Indeed the etymological origin of the words: mensuration (to measure), menstruation (women's period), and month; are all derived from the Moon. The waxing and waning phases of the Moon give us each a two week period. Which divided in two give us a week of seven days.

Krsna's energy

From examining the scriptures we can make few basic conclusions:

1) The identity of Krsna with time, or more properly that time is one of Krsna's energies.

2) Krsna as the time factor causes the material creation.

3) Time has very serious effects on the living beings.

4) The spiritual world is free of time's destructive influence.

1) Kala (time) is a special manifestation of Krsna's energy.

"The Supreme Personality of Godhead said: Time I am, the great destroyer of the worlds, and I have come here to destroy all people..." (BG 11.32)

"My Lord, I consider Your Lordship to be eternal time, the supreme controller, without beginning and end, the all-pervasive one. In distributing Your mercy, You are equal to everyone. The dissensions between living beings are due to social intercourse." (SB 1.8.28)

"The time factor, who causes the transformation of the various material manifestations, is another feature of the Supreme Personality of Godhead. Anyone who does not know that time is the same Supreme Personality is afraid of the time factor." (SB 3.29.37)

"Lord Visnu, the Supreme Personality of Godhead, who is the enjoyer of all sacrifices, is the time factor and the master of all masters. He enters everyone's heart, He is the support of everyone, and He causes every being to be annihilated by another." (SB 3.29.38)

2) Kala, the time factor, causes material creation.

"The Supreme Living Being in His feature as the transcendental purusa incarnation, who is the Lord's plenary expansion, impregnates the material nature of three modes, and thus by the influence of eternal time the living entities appear." (SB 3.5.26)

"Thereafter, influenced by the interactions of eternal time, the supreme sum total of matter called the mahat-tattva became manifested, and in this mahat-tattva the unalloyed goodness, the Supreme Lord, sowed the seeds of universal manifestation out of His own body." (SB 3.5.27)

Time is described as Lord's glance (personified as Siva) on the material nature initiating the creation process. (BG 14.3-4, SB 3.5.26-27, Brahma-samhita 5.10) Siva's paraphernalia symbolize: moon - time measurement in months, three eyes - tri-kala-jna, snake around the neck - time measurement in years, necklace of skulls with snakes - changing of ages and begetting and annihilating of mankind.

"Maitreya said: Eternal time is the primeval source of the interactions of the three modes of material nature. It is unchangeable and limitless, and it works as the instrument of the Supreme Personality of Godhead for His pastimes in the material creation." (SB 3.10.11)


The impersonal time factor is the background of the material manifestation as the instrument of the Supreme Lord. It is the ingredient of assistance offered to material nature. No one knows where time began and where it ends, and it is time only which can keep a record of the creation, maintenance and destruction of the material manifestation. This time factor is the material cause of creation and is therefore a self expansion of the Personality of Godhead. Time is considered the impersonal feature of the Lord. ...Metaphysically, time is distinguished as absolute and real. Absolute time is continuous and is unaffected by the speed or slowness of material things. Time is astronomically and mathematically calculated in relation to the speed, change and life of a particular object. Factually, however, time has nothing to do with the relativities of things; rather, everything is shaped and calculated in terms of the facility offered by time. Time is the basic measurement of the activity of our senses, by which we calculate past, present and future; but in factual calculation, time has no beginning and no end. Canakya Pandita says that even a slight fraction of time cannot be purchased with millions of dollars, and therefore even a moment of time lost without profit must be calculated as the greatest loss in life. Time is not subject to any form of psychology, nor are the moments objective realities in themselves, but they are dependent on particular experiences. Therefore, Srila Jiva Gosvami concludes that the time factor is intermixed with the activities - actions and reactions - of the external energy of the Lord. The external energy, or material nature, works under the superintendence of the time factor as the Lord Himself, and that is why material nature appears to have produced so many wonderful things in the cosmic manifestation. Bhagavad-gita (9.10) confirms this conclusion as follows: 'This material nature, which is one of My energies, is working under My direction, O son of Kunti, producing all moving and nonmoving beings. Under its rule this manifestation is created and annihilated again and again.'

"This cosmic manifestation is separated from the Supreme Lord as material energy by means of kala, which is the unmanifested, impersonal feature of the Lord. It is situated as the objective manifestation of the Lord under the influence of the same material energy of Visnu." (SB 3.10.12)

Verses 11 and 12 give us a much deeper understanding of the influence of time on the material creation. We see in verse 12 that it is time itself which is the factor that causes the material energy to be 'material' by virtue of separating this energy from the Lord.

From the Lord's perspective it is all one energy, His spiritual energy, but from our perspective His energy appears to differentiate into spiritual and material. For example the electricity can be used to create heat in an oven or to make ice in the freezer. It depends on how it is used. It can thus be understood from this verse that it is time, one of Krsna's energies, which actually causes the transformation of the spiritual energy into material energy and separates it from Krsna.

It is by virtue of being separated from Krsna that distinguishes the material from the spiritual energy. When the energy is separated from Krsna it becomes Maya. Maya, by definition, means not Krsna. The Maya energy, i.e. the material energy is not Krsna because it is not related to Krsna but separated from Him. The jiva, the living being, is not material but spiritual and is superior to matter, and is always related to Krsna.

"Earth, water, fire, air, ether, mind, intelligence and false ego - all together these eight constitute My separated material energies. "Besides these, O mighty-armed Arjuna, there is another, superior energy of Mine, which comprises the living entities who are exploiting the resources of this material, inferior nature." (BG 7.4-5)

"The eternal time factor has no beginning and no end. It is the representative of the Supreme Personality of Godhead, the maker of the criminal world. It brings about the end of the phenomenal world, it carries on the work of creation by bringing one individual into existence from another, and likewise it dissolves the universe by destroying even the lord of death, Yamaraja." (SB 3.29.45)


By the influence of eternal time, which is a representative of the Supreme Personality of Godhead, the father begets a son, and the father dies by the influence of cruel death. But by time's influence, even the lord of cruel death is killed. In other words, all the demigods within the material world are temporary, like ourselves. Our lives last for one hundred years at the most, and similarly, although their lives may last for millions and billions of years, the demigods are not eternal. No one can live within this material world eternally. The phenomenal world is created, maintained and destroyed by the finger signal of the Supreme Personality of Godhead. Therefore a devotee does not desire anything in this material world. A devotee desires only to serve the Supreme Personality of Godhead. This servitude exists eternally; the Lord exists eternally, His servitor exists eternally, and the service exists eternally.

The quality of stirring up the material elements and getting the material creation going is explained in the following verses:

"All these are considered the qualified Brahman. The mixing element, which is known as time, is counted as the twenty-fifth element." (SB 3.26.15)

"The influence of the Supreme Personality of Godhead is felt in the time factor, which causes fear of death due to the false ego of the deluded soul who has contacted material nature." (SB 3.26.16)

"My dear mother, O daughter of Svayambhuva Manu, the time factor, as I have explained, is the Supreme Personality of Godhead, from whom the creation begins as a result of the agitation of the neutral, unmanifested nature." (SB 3.26.17)

"By exhibiting His potencies, the Supreme Personality of Godhead adjusts all these different elements, keeping Himself within as the Supersoul and without as time." (SB 3.26.18)

3) Time has very serious effects on the living beings.

It is time, the impersonal aspect of Sri Krsna, which activates the material elements and captures the spiritual spark in a tangle of activities and karma. For we speak of karma as past-karma, present-karma and future-karma. And it is the living being who is subject to karma and thus to time. This doesn't mean that time and karma are synonymous. As stated in the introduction of the Bhagavad Gita - time and karma are two of the five topics of the Gita, along with God, the individual soul, and material energy. Of these five subjects four are eternal but karma is not eternal. So there is distinction between karma and time. But they do interact.

"Whoever is under the influence of supreme kala [eternal time] must surrender his most dear life, and what to speak of other things, such as wealth, honor, children, land and home." (SB 1.13.20)

"This gross material body made of five elements is already under the control of eternal time [kala], action [karma] and the modes of material nature [guna]. How, then, can it, being already in the jaws of the serpent, protect others?" (SB 1.13.46)

"The Personality of Godhead said: As a mass of clouds does not know the powerful influence of the wind, a person engaged in material consciousness does not know the powerful strength of the time factor, by which he is being carried." (SB 3.30.1)

"Whatever is produced by the materialist with great pain and labor for so-called happiness, the Supreme Personality, as the time factor, destroys, and for this reason the conditioned soul laments." (SB 3.30.2)


The main function of the time factor, which is a representative of the Supreme Personality of Godhead, is to destroy everything. The materialists, in material consciousness, are engaged in producing so many things in the name of economic development. They think that by advancing in satisfying the material needs of man they will be happy, but they forget that everything they have produced will be destroyed in due course of time. From history we can see that there were many powerful empires on the surface of the globe that were constructed with great pain and great perseverance, but in due course of time they have all been destroyed. Still the foolish materialists cannot understand that they are simply wasting time in producing material necessities, which are destined to be vanquished in due course of time. This waste of energy is due to the ignorance of the mass of people, who do not know that they are eternal and that they have an eternal engagement also. They do not know that this span of life in a particular type of body is but a flash in the eternal journey. Not knowing this fact, they take the small flash of life to be everything, and they waste time in improving economic conditions.

"The Supreme Personality of Godhead, by His inconceivable supreme energy, time, causes the interaction of the three modes of material nature, and thus varieties of energy become manifest. It appears that He is acting, but He is not the actor. He is killing, but He is not the killer. Thus it is understood that only by His inconceivable power is everything happening." (SB 4.11.18)

"My dear Dhruva, the Supreme Personality of Godhead is ever existing, but in the form of time, He is the killer of everything. He has no beginning, although He is the beginning of everything, nor is He ever exhaustible, although everything is exhausted in due course of time. The living entities are created through the agency of the father and killed through the agency of death, but He is perpetually free of birth and death." (SB 4.11.19)

"The Supreme Personality of Godhead, in His feature of eternal time, is present in the material world and is neutral towards everyone. No one is His ally, and no one is His enemy. Within the jurisdiction of the time element, everyone enjoys or suffers the result of his own karma, or fruitive activities. As, when the wind blows, small particles of dust fly in the air, so, according to one's particular karma, one suffers or enjoys material life." (SB 4.11.20)

"My dear Lord, Your absolute authority cannot be directly experienced, but one can guess by seeing the activities of the world that everything is being destroyed in due course of time. The force of time is very strong, and everything is being destroyed by something else - just as one animal is being eaten by another animal. Time scatters everything, exactly as the wind scatters clouds in the sky." (SB 4.24.65)

"Since the material body is sure to be vanquished and the duration of one's life is not fixed, neither death nor life is to be praised. Rather, one should observe the eternal time factor, in which the living entity manifests himself and disappears." (SB 7.13.6)

"No one can surpass the time representation of the Supreme Personality of Godhead by material power, by the counsel of ministers, by intelligence, by diplomacy, by fortresses, by mystic mantras, by drugs, by herbs or by any other means." (SB 8.21.22)

4) The spiritual world is free of time's destructive influence.

"In that personal abode of the Lord, the material modes of ignorance and passion do not prevail, nor is there any of their influence in goodness. There is no predominance of the influence of time, so what to speak of the illusory, external energy; it cannot enter that region. Without discrimination, both the demigods and the demons worship the Lord as devotees." (SB 2.9.10)

The affairs of the material world look unreal from the vantage point of the spiritual world: "All that happens in time - past, present and future - is a dream. This is the secret understanding of all Vedic literatures." (SB 4.29.2b)

Calculation of time (SB 3.11.1-12)

The atomic description of the Srimad Bhagavatam is almost the same as that of modern science. This is further described in the Paramanu-vada of Kanada. Time is measured in terms of its covering a certain space of atoms. Standard time is calculated in terms of the movement of the sun. The time covered by the sun in passing over an atom is calculated as atomic time.

Two atoms
Three double atoms
Three hexatoms

One hundred trutis
Three vedas
Three lavas
Three nimesas
Five ksanas
Fifteen kasthas
Fifteen laghus
Two dandas
Six to seven dandas
Fifteen days and nights
Two fortnights
- a double atom
- a hexatom (a particle visible in sunshine)
- a truti or 18 atomic particles, or one second
divided in 16,875 parts.
- one veda
- one lava
- one nimesa
- one ksana
- one kastha or 8 seconds
- one laghu or 2 minutes
- one (nadika-danda) or 30 minutes
- one muhurta or one hour
- one prahara or quarter of a day
- two weeks or a fortnight
- one month

During the period of one month the moon wanes and is called krsna-paksa, the dark moon or amavasya. In the same month the moon waxes and is called gaura-paksa or sukla-paksa, the full moon or purnima. Thus purnima to amavasya is called krsna-paksa (dark moon) and amavasya to purnima is called sukla-paksa (bright moon). Two months equal one season. During the first six months the sun travels from south to north (uttarayana). During the second six months the sun travels from north to south (daksinayana). Two solar movements equal one day and night of the demigods.

Four cosmic ages (yugas)

When explaining the various measurements of time, Vishnu Purana (1.3), Srimad Bhagavatam (3.11.18-39), Bhagavad-gita (8.17), Vayu Purana (chapter 57) and others, such as the Mahabharata (Shanti Parva, 231.12-20), all agree on the measurements of the durations of the yugas, as explained below.

One cycle of the four yugas together is 12,000 years of the devas called divine years. Each of these years is composed of 360 days, and each of their days is equal to one human year. So Krta-yuga is 4000 divine years in length, Treta-yuga is 3000 divine years in length, Dvapara-yuga is 2000 divine years in length, and Kali-yuga is 1000 divine years long, with the addition of the conjoining portions of the sandhya and sandhyamsa. Each yuga is preceded by a period called a sandhya, which is as many hundred years in length as there are thousands of years in that particular yuga. Each yuga is also followed by a period of time known as a sandhyamsa of the same length. In between these periods of time is the actual yuga.

Krta or Satya-yuga (Golden Age)

Duration - 4,800 demigods years (4000 + 400 sandhya + 400 sandhyamsa)
or 1,728,000 human years
Life span - 100,000 years (Brahma vaivarta Purana 4.90.12, SB 4.12.13: Dhruva Maharaja ruled for 36,000 years)
Yuga-dharma (SB 12.3.52 lists all yuga dharmas) - meditation or astanga yoga
Yuga-avatara - white with four arms, has matted hair and wears a garment of tree bark. He carries a black deerskin, a sacred thread, prayer beads and the rod and waterpot of a brahmacari. (SB 11.5.21)

Symptoms of Satya-yuga: The people are peaceful, non-envious, friendly and naturally Krsna conscious. In Satya-yuga there was no division of asrama, everyone was a paramahamsa. There was no demigod worship, only the worship of Krsna and religion was perfectly practiced. (SB 9.14, 11.5.21-22)

Treta-yuga (Silver Age)

Duration - 3,600 demigod years (3000 + 300 sandhya + 300 sandhyamsa)
or 1,296,000 human years
Life span - 10,000 years (SB 5.17.12)
Yuga-dharma - Fire sacrifice (yajna)
Yuga-avatara - red with four arms and golden hair. He wears a triple belt representing initiation into the three Vedas. His symbols are the sruk, sruva, etc. (ladle, spoon and other implements of sacrifice).

Symptoms of Treta-yuga: In Treta-yuga the people are thoroughly religious. In Satya-yuga people are naturally Krsna conscious. In Treta-yuga they are inclined to become Krsna conscious. To achieve that end they are very strict in following Vedic principles.

Dvapara-yuga (Copper Age)

Duration - 2,400 demigod years (2000 + 200 sandhya + 200 sandhyamsa)
or 864,000 human years
Life span - 1,000 years
Yuga-dharma - Temple worship (arcana)
Yuga-avatara - his complexion is dark blue. He wears yellow garments. His body is marked with Srivatsa and other distinctive ornaments, and He manifests His personal weapons.

The original Personality of Godhead from whom all other incarnations expand is Sri Krsna. He appears once in a day of Brahma, during the period of the seventh Manu (Vaivasvata) in the 28th divya-yuga. The original Personality of Godhead Krsna only comes once in a day of Brahma. Although in every Dvapara-yuga there is a yuga-avatara, they are all expansions of Visnu, who is an expansion of Sri Krsna.

Symptoms of Dvapara-yuga: In Dvapara-yuga people have the weaknesses of mortal beings, but they have a strong desire to know about the Absolute Truth and they worship the Lord in the mood of honoring a great king, following the prescriptions of both Vedas and tantras.

Kali-yuga (Iron Age)

Duration - 1,200 demigod years (1000 + 100 sandhya + 100 sandhyamsa)
or 432,000 human years
Life span - 100 years
Yuga-dharma - Chanting the Hare Krsna mahamantra (harinama sankirtana)
Yuga-avatara - golden or yellow but generally black. Lord Caitanya, who is Krsna Himself, appears only in the Kali-yuga immediately following the appearance of Sri Krsna in Dvapara-yuga.

Symptoms of Kali-yuga: "O learned one in the age of Kali, men have but short lives. They are quarrelsome, lazy, misguided unlucky and above all, always disturbed." (SB 1.1.10)

The four yugas are known as a divya-yuga, or maha-yuga. One divya-yuga is 12,000 years of the demigods (4,320,000 human years). One thousand divya-yugas equals one day of Brahma (4,320,000,000 human years).

In each Brahma's day there are fourteen Manus (patriarchs of mankind). Each Manu enjoys a life of seventy-one divya-yugas or 852,000 years of the demigods (306,720,000 human years). After the dissolution of every Manu a new Manu comes. With the change of Manu the universal management also changes. Each manvantara is preceded and followed by the yuga-sandhya in length of one Satya-yuga. The yuga-sandhyas are periods of partial devastation and creation.

Brahma's life consists of 36,000 days and nights (of the same length), or 311,040,000,000,000 human years.

We live in Kali-yuga of the 28th divya-yuga of the 7th Manu of the 12th kalpa (called Sveta-Varaha) (SB 2.10.46p., Skanda P. 2.39-42), in the 51th year of Brahma. The beginning of this kalpa was 2.3 billion years ago (453 mahayugas back).

Related links:

Vedic Astrology
Holy Days and Vaisnava festivals
Astronomy and Antiquity of Vedic Culture
Puranic Time and the Archaeological Record