According to Hindu vedic cosmology, there is no absolute start to time, as it is considered infinite and cyclic. Similarly, the space and universe has neither start nor end, rather it is cyclical. The current universe is just the start of a present cycle preceded by an infinite number of universes and to be followed by another infinite number of universes.
The dominant theme in Puranic Hindu cosmology, state Chapman and Driver, is of cycles and repetition. There are multiple universes, each takes birth from chaos, grows, decays and dies into chaos, to be reborn again. Further, there are different and parallel realities. Brahma's one day equals 4.32 billion years which is a Kalpa. Each Kalpa is subdivided into four yuga (chaturyuga, also called mahayuga). These are krita (or satya), treta, dvapara and kali yugas. The current time is stated to be one of kali yuga. The starting year, length of each, or the grand total, is not consistent in the Puranas. According to Ludo Rocher, the total of four yugas is typically 4,320,000 years, of which 432,000 years is assigned to be the duration of the kali yuga.[note 1]
One complete cycle of the four (Kṛta or Satya, Treta, Dvapara and Kali) Yugas is one Mahā-Yuga (4.32 million solar years) and is confirmed by the Gītā Śloka 8.17 (statement) "sahasra-yuga-paryantam ahar yad brahmaṇo viduḥ rātriṁ yuga-sahasrāntāṁ te 'ho-rātra-vido janāḥ", meaning, a day of brahma is of 1000 Mahā-Yuga. Thus a day of Brahma, Kalpa, is of duration: 4.32 billion solar years. Two Kalpas constitute 24 hours (day and Night) of Brahma. A Manvantara, which consists of 71 Mahā-Yuga (306,720,000 solar years) is ruled by a Manu. After each Manvantara follows one Sandhi Kāla, of the same duration as a Kṛta Yuga (1,728,000 Solar Years). It is said that during a Sandhi Kāla, the entire earth is submerged in water. According to Hindu scriptures, the world would be destroyed at the end of the Kali Yuga.
Rigveda: speculation on universe's creationEdit
- Hiranyagarbha sukta, its hymn 10.121, states a golden child was born in the universe and was the lord, established earth and heaven, then asks but who is the god to whom we shall offer the sacrificial prayers?
- Devi sukta, its hymn 10.125, states a goddess is all, the creator, the created universe, the feeder and the lover of the universe;
- Nasadiya sukta, its hymn 10.129, asks who created the universe, does anyone really know, and whether it can ever be known.
According to Henry White Wallis, the Rigveda and other Vedic texts are full of alternative cosmological theories and curiosity questions. For example, the hymn 1.24 of the Rigveda asks, "these stars, which are set on high, and appear at night, whither do they go in the daytime?" and hymn 10.88 wonders, "how many fires are there, how many suns, how many dawns, how many waters? I am not posing an awkward question for you fathers; I ask you, poets, only to find out?" To its numerous open-ended questions, the Vedic texts present a diversity of thought, in verses imbued with symbols and allegory, where in some cases forces and agencies are clothed with a distinct personality, while in other cases as nature with or without anthropomorphic activity such as forms of mythical sacrifices.
The Rigveda contains the Nasadiya sukta hymn which does not offer a cosmological theory, but asks cosmological questions about the nature of universe and how it began:
Darkness there was at first, by darkness hidden;
Without distinctive marks, this all was water;
That which, becoming, by the void was covered;
That One by force of heat came into being;
Who really knows? Who will here proclaim it?
Whence was it produced? Whence is this creation?
Gods came afterwards, with the creation of this universe.
Who then knows whence it has arisen?
Whether God's will created it, or whether He was mute;
Perhaps it formed itself, or perhaps it did not;
Only He who is its overseer in highest heaven knows,
Only He knows, or perhaps He does not know.
Vedic: 3 lokasEdit
Deborah Soifer describes the development of the concept of lokas as follows:
The concept of a loka or lokas develops in the Vedic literature. Influenced by the special connotations that a word for space might have for a nomadic people, loka in the Veda did not simply mean place or world, but had a positive valuation: it was a place or position of religious or psychological interest with a special value of function of its own. Hence, inherent in the 'loka' concept in the earliest literature was a double aspect; that is, coexistent with spatiality was a religious or soteriological meaning, which could exist independent of a spatial notion, an 'immaterial' significance. The most common cosmological conception of lokas in the Veda was that of the trailokya or triple world: three worlds consisting of earth, atmosphere or sky, and heaven, making up the universe."
Puranas: 14 lokasEdit
The later Puranic view asserts that the Universe is created, destroyed, and re-created in an eternally repetitive series of cycles. A day of Brahma, the creator, endures for about 4,320,000,000 years.
In the Brahmanda Purana, there are fourteen worlds. However, other Puranas give different version of this cosmology and associated myths. In the Brahmanda version, the loka consist of seven higher ones (Vyahrtis) and seven lower ones (Pātālas), as follows:
- Bhuloka, Bhuvar Loka, svarga, Mahar Loka, Jana Loka, Tapa Loka, and Satyaloka above, and
- Atala, Vitala, Sutala, Rasaataala, Talatala, Mahaatala, Patala and naraka below.
The Puranas genre of Indian literature, found in Hinduism and Jainism, contain a section on cosmology and cosmogony as a requirement. There are dozens of different Mahapuranas and Upapuranas, each with its own theory integrated into a proposed human history consisting of solar and lunar dynasties. Some are similar to Indo-European creation myths, while others are novel. One cosmology, shared by Hindu, Buddhist and Jain texts involves Mount Meru, with stars and sun moving around it using Dhruva (North Star) as the focal reference. According to Annette Wilke and Oliver Moebus, the diversity of cosmology theories in Hinduism may reflect its tendency to not reject new ideas and empirical observations as they became available, but to adapt and integrate them creatively.
Multiverse in HinduismEdit
Every universe is covered by seven layers — earth, water, fire, air, sky, the total energy and false ego — each ten times greater than the previous one. There are innumerable universes besides this one, and although they are unlimitedly large, they move about like atoms in You. Therefore You are called unlimited (Bhagavata Purana 6.16.37)
Analogies to describe multiple universes also exist in the Puranic literature:
Because You are unlimited, neither the lords of heaven nor even You Yourself can ever reach the end of Your glories. The countless universes, each enveloped in its shell, are compelled by the wheel of time to wander within You, like particles of dust blowing about in the sky. The śrutis, following their method of eliminating everything separate from the Supreme, become successful by revealing You as their final conclusion (Bhagavata Purana 10.87.41) 
The layers or elements covering the universes are each ten times thicker than the one before, and all the universes clustered together appear like atoms in a huge combination (Bhagavata Purana 3.11.41)
And who will search through the wide infinities of space to count the universes side by side, each containing its Brahma, its Vishnu, its Shiva? Who can count the Indras in them all--those Indras side by side, who reign at once in all the innumerable worlds; those others who passed away before them; or even the Indras who succeed each other in any given line, ascending to godly kingship, one by one, and, one by one, passing away (Brahma Vaivarta Purana) 
According to Carl Sagan:
|“||"The Hindu religion is the only one of the world's great faiths dedicated to the idea that the Cosmos itself undergoes an immense, indeed an infinite, number of deaths and rebirths. It is the only religion in which time scales correspond to those of modern scientific cosmology. Its cycles run from our ordinary day and night to a day and night of Brahma, 8.64 billion years long, longer than the age of the Earth or the Sun and about half the time since the Big Bang."||”|
- The concept of four cosmic periods (yuga) is also found in Greek, Roman, Irish and Babylonian mythologies, where each age becomes more sinful and of suffering. For example, the Roman version found in the early 1st-century Metamorphoses of Ovid calls it Silvern (white), Golden (yellow), Bronze (red) and Iron (black) ages. Plato too divides the concept of universal time into ages, and suggests time being cyclic. The total number of years in the Babylonian mythology is the same 432,000 years (120 saroi) as the Indian mythologies.
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