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 VEDA 
jñānena tu tad ajñānam yeṣāṃ nāśitam ātmanaḥ | teṣām ādityavaj jñānaṃ prakāśayati tat param
“As the sun dispels darkness and illuminates everything, so divine knowledge destroys ignorance and reveals the transcendental Absolute Truth.” — Bhagavad-Gītā 5.16    

The Four Ages

According to Vedic understanding, there are four ages:

  1. Satya-Yuga; Kṛta-Yuga; the age of truthfulness; golden age
  2. Treta-Yuga
  3. Dvāpara-Yuga
  4. Kali-Yuga; iron age; the age of quarrel and hypocrisy

Duration of the four Ages

According to earthly time calculation

They last a total of 4,320,000 years according to earthly calendar and repeat cyclically like spring, summer, autumn and winter. The present age is called Kali-Yuga, the age of quarrel and hypocrisy. From the kali-yuga, only about 5,000 years have passed.

The Dvāpara Age lasts twice as long as the Kali Yuga, the Treta Yuga three times as long and the Satya Yuga four times as long.

Yuga Duration
Satya-Yuga 1,728,000 years
Treta-Yuga 1,296,000 years
Dvāpara-Yuga 864,000 years
Kali-Yuga 432,000 years
Total 4,320,000 years
According to heavenly time calculation

According to the time calculation of the Devas (demigods) in the higher regions of the universe, the total duration of a Yuga cycle is 12,000 years. One day of the Devas equals 360 days (1 year) on the earth planet.

Yuga Duration
Satya-Yuga 4,800 years
Treta-Yuga 3,600 years
Dvāpara-Yuga 2,400 years
Kali-Yuga 1,200 years
Total 12,000 years
Kalpa – one day of Brahma

1000 such catur-yuga cycles (4.32 billion years) are 1 day in the life of Lord Brahma. Brahma is the creator of the 14 worlds of a universe and he dwells in his region in the topmost of the fourteen worlds. As a Guna-avatara who controls rajo-guna, the material mode of passion, he is responsible for creation. At the end of the day, he lies down to rest. Then nothing exists below his region. His night lasts as long as his day. Upon awakening, he begins creation anew. Brahma's life lasts 100 heavenly years, an unimaginably long time. The universe exists for the same length of time. There are countless universes. The process of creation and annihilation of the material world, which is compared to a cloud in the spiritual sky, is eternal. Clouds appear and dissolve again. There is no end and no beginning. This is all explained in more detail in the article Creation and Dissolution of the Material World.

Wrong speculations about the four Ages

On some websites and in videos, only the celestial calendar for the earth is mentioned for the duration of the four ages. There is even speculation that we are at the beginning of a new golden age, a satya-yuga. Maharishi Mahesh Yogi (“Transcendental Meditation”) proclaimed a new golden age in the 1960's. Other speculators have spread the word that a new golden age began at the end of 2012. They refer to the Mayan calendar, according to which a new age began in 2012.

That we are in fact at the beginning of a kali-yuga is proved by the statements of the Śrīmad-Bhāgavatam, the Mahābhārata and other Vedic scriptures. From the descriptions and characteristics mentioned for the four ages, one can easily deduce that we are at the beginning of an iron age.

Features of the four Ages

The three gunas sattva, rajas, tamas

In the kṛta-yuga, sattva-guṇa, the material mode of purity, virtue, goodness, is predominant; in the tretā-yuga sattva-guṇa and rajo-guṇa, the mode of passion; in the dvāpara-yuga rajo-guṇa and in the kali-yuga tamo-guṇa, the mode of ignorance, is predominant.

Satya-Yuga

In the satya-yuga, the earth produces first-class food with excellent taste in abundance. People are bursting with energy like the ādityas (demigods). They can directly perceive the devas and celestial rishis (sages). Their bodies are beautiful, strong as the wind and firm as mountains, their intelligence and senses are keen and their radiance is clear. They are filled with joy, non-violent, self-controlled, simple, truthful, renounced, and they are free from fear, greed, illusion, lust, anger, envy, attachment, fatigue, disease and the tendency to accumulate things. They devote themselves to meditation in astānga-yoga, perform sacrifices according to the instructions of the Vedas, etc. Because of these qualities, they possess a very long life. Towards the end of the kṛta-yuga, some people slacken somewhat in their renunciation (their yoga practice) and thus heaviness arises in their bodies. Heaviness leads to fatigue and fatigue makes them feel sluggish. Sluggishness makes them accumulate things; the accumulation of things leads to attachment – the more one possesses, the more attached he is to his possessions – and attachment finally brings about greed. We see here how the mode of purity (sattva-guṇa) in a person gradually gives way to the mode of passion (rajo-guṇa) when a person anchored in sattva-guṇa becomes careless in his renunciation.

Tretā-Yuga

In the tretā-yuga, rajo-guṇa gains further influence. Greed gradually develops into malice, lies, anger, passion, deceit, crudeness, violence, fear, worry, sorrow, etc. Dharma is symbolically represented as a bull. His four legs represent mercy, cleanliness, abstinence and truthfulness. In the tretā-yuga, dharma stands on only three legs, i.e. dharma is reduced by a quarter. As a result, the life span of people is shortened. Due to reduction in the quality of plants and food (in purity, taste, energy and specific power etc.) and due to people's behaviour, maruta (vāta) and agni (digestive fire) are affected and thus the first diseases like jvara [various types of fever] etc. can manifest.

Dvāpara-Yuga

In the dvāpara, dharma again decreases by a quarter – the bull of religion stands on only two legs –, food continues to lose taste, strength, digestibility and other qualities, people's resistance weakens and the manifestation of diseases increases. At the end of the dvāpara-yuga, tamo-guṇa gains influence and becomes the dominant factor in the course of the following age.

Kali-Yuga

Then dharma stands only on one leg – there is not much left of mercy, abstinence, cleanliness and truthfulness. In the kali-yuga, people possess little intelligence, poor memory, no mercy, are always disturbed, etc. The age of Kali began only 5000 years ago, which means it will take another 427,000 years for a new kṛta-yuga to blossom. Until then, the world will be ruled by Kali,1 the lord of this age. Kali's abodes are mainly gambling dens, brothels, pubs, slaughterhouses, stock exchanges etc., places where money and gold, prostitution, intoxication etc. prevail.

Kali, the Lord of Kali-Yuga

In this context, Śukadeva Gosvāmī tells the following story in the Śrīmad-Bhāgavatam: At the end of the dvāpara, when Mahārāja Yudhiṣṭira was ruling the world, it happened that on a journey he saw a black man beating a cow. That man was Kali. Enraged by this monstrous act of Kali, Yudhiṣṭira drew his sword and instantly wanted to cut off the head of the sacrilegious man. Kali whimpered and begged for forgiveness. Yudhiṣṭira took pity on him, spared his life and ordered him to leave his kingdom immediately. But Kali replied, “Where shall I go? Since you rule, righteousness prevails everywhere and there is no place for my stay.” Yudhiṣṭira replied, “Wherever money and gold are hoarded, wherever people indulge in gambling, intoxication, illicit sexuality and meat-eating, that is your place.”

At that time, there were not many places for Kali, but after Yudhiṣṭira's death, irreligiosity took over more and more and Kali is now at home in almost every place.

Citations from the Srimad-Bhagavatam

In the 12th Canto of the Śrīmad-Bhāgavatam there is a description of the symptoms of the Kali age, some of which have already manifested or will manifest as this age progresses. It says:

Śukaveda Goswami said, “Then, O king, religion, truthfulness, cleanliness, forbearance, life span, physical strength and memory will dwindle day by day due to the powerful influence of the Kali age.” (S.-B. 12.2.1)

“In the Kali-yuga, wealth alone will be regarded as the sign of a man's noble birth, right conduct and good qualities, and law and jurisprudence will be applied only on the basis of someone's power.” (S.-B. 12.2.2)

“Men and women will live together only because of superficial attraction and business success will depend on deceit. . .” (S.-B. 12.2.3)

“. . . And someone who is very skilled at playing with words will be considered a scholar.” (S.-B. 12.2.4)

“A person will be considered impious if he does not possess money and hypocrisy will be considered as virtue . . .” (S.-B. 12.2.5)

“. . . To fill the stomach will be the aim of life and audacity will be regarded as truthfulness. He who can maintain a family will be considered an experienced man and religious principles will be followed only for the sake of reputation.” (S.-B. 12.2.6)

“With the increase of corrupt population, those people of the social classes who are strongest will gain political power.” (S.-B. 12.2.7)

“The citizens will suffer severely from cold, heat, rain, wind and snow. They will be further plagued by quarrels, hunger, thirst, diseases and serious worries.” (S.-B. 12.2.10)

“Cities will be populated by thieves; the Vedas will be polluted by speculative interpretations of atheists; political leaders will practically consume the citizens (exploit them through taxes etc.) and so-called priests and intellectuals will be devoted worshippers of their own stomachs and private parts.” (S.-B. 12.3.32)

“O King, in the age of Kali, people's intelligence will be characterised by atheism and they will almost never perform sacrifices to the Supreme Personality of Godhead, who is the supreme spiritual master of the universe. Although the great personalities who rule the three worlds (Brahmā, Śiva, Indra, etc.) all bow down at the lotus feet of the Supreme Lord – the insignificant and wretched people of this age will not.

A man lies dying, overwhelmed by fear of death. Though his voice is broken and he is hardly aware of what he is saying, he can be freed from the reactions to his fruitive actions (fruitive action – whether sinful or pious – means being reborn) and attain the highest destiny by speaking the Holy Name of the Lord. But still, in the Kali-yuga, people will not worship the Supreme Lord.” (Ś.-B. 12.3.43–44)

Citations frome the Mahabharata

“After the disappearance of royal duties and the science of just punishment (danda), a mingling of social classes will set in and innumerable pseudo-monks painted with various marks will appear. Disregarding the Purānas and the sublime truths of religion, people, driven by lust and anger, will walk on false paths.”

“In the kali-yuga, however, there is no fixed limit to the length of life, for some people die in the womb and others shortly after birth. People of the Kali age possess no strength, are extremely angry, greedy and untruthful. Jealousy, pride, anger, deceit, malice and greed dominate people in the kali yuga.”2

“The man of low intelligence who destroys the weight of authority (of the Vedas and the teachers of the Vedas) by denying what has always been accepted as standard becomes the cause of great sorrow in the world.”

“The king makes the age. When the king rules in strict accordance with the science of just punishment, the best of all ages, the satya-yuga (satya means truthfulness), sets in. With the satya-yuga, righteousness sets in; sin does not exist. The hearts of all people find no pleasure in sinfulness. Without doubt, all men attain what they aspire to and retain what they possess. All Vedic rites produce merit. All seasons are pleasant and free from evil. People's voices and speech are clear, and their minds are joyful. Diseases do not exist and all people live long. Wives do not become widows, and no one becomes a miser. In the satya-yuga, the earth produces herbs, vegetables and grains in abundance without the need for ploughing. The barks, leaves, fruits and roots are nourishing and strength-giving. Know that these are the characteristics of the satya-yuga, O Yudhiṣṭira.”

“And the virtuous do not succeed, while the sinful succeed beyond measure. And virtue loses its power, while sin becomes all-powerful. And the people who are devoted to virtue become poor and short-lived; but those who are sinful become long-lived and gain wealth.” (— Markandeya speaks to Yudhiṣṭira and his companions about the Kali-Yuga)

“And, O king, then girls will become pregnant at the age of seven or eight, while boys will beget offspring at the age of ten or twelve. And in their sixteenth year men will be overcome with decrepitude and decay, and their lifetime will soon be expired.” (— Markandeya speaks to Yudhiṣṭira and his companions about the end time of the Kali-Yuga)

“And, O king, the women then become mothers of numerous offspring who are of small stature and lacking in good behaviour and good manners. And they also make their own mouths serve the purpose of procreation. And famines ravage the dwellings of men, and the streets will be filled with women of ill repute, while the women in general, O king, at such times are hostile to their husbands and no longer possess decency. And, O king, the cows at such times give but little milk, while the trees, peopled by flocks of crows, do not produce many flowers and fruits.” (— Markandeya speaking to Yudhiṣṭira and his companions about the end time of Kali-Yuga)

“And, O Lord of men, numerous mleccha regents then rule the earth! And these sinful mighty ones, given to false speech, govern their subjects according to false principles. This, O tiger among men, is the state of the world before the evening of the Kali age! Not a single Brahmin then abides by the duties of his class. And even the Kshatriyas and the Vaisyas, O rulers, follow practices contrary to those proper to their own class. And men become short-lived, weak in strength, energy and skill; and endowed with little strength and small bodies, they will hardly speak truthfully. And the human population dwindles over vast areas, and the regions of the earth, north and south, east and west, will be populated by many beasts and predators.” (— Markandeya speaks to Yudhiṣṭira and his companions about the end times of the Kali-Yuga)

We are indeed at the beginning of a Kali-Yuga, an iron machine age, which can be clearly seen in the material circumstances of life, natural events, all the wars, chaos, suffering and destruction, etc., but:

This Kali Yuga is special in spiritual terms, at least for now. Not in every Kali Yuga are the opportunities for spiritual development as favourable as in the present one. (See more at: Yuga-dharma – Religion in the 4 Ages)

Footnotes

1 Not to be confused with the goddess Kālī.

2 Sanjaya instructs the old blind king Dhritarāṣtra, whose godless son Duryodhana had fraudulently deprived Yudhiṣṭira of his rule and fought against Yudhiṣṭira Mahārāja and his brothers in the great battle of Kurukṣetra.