The concept of Srishti described in Mahabharata
Srishti (Creation)
In Vedic cosmology, the universe is cyclically created and destroyed. The Hindu timeline is considered by some to be the closest to modern scientific timelines. It suggests that the Big Bang is not the beginning of everything, but 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.
Brahma's day and night each consist of 1,000 Maha Yugas or 1 Kalpa, measuring 4.32 billion human years, during which life and the human race appear and then disappear. A Kalpa consists of 14 Manvantaras and 15 Sandhi Kalas. Manvantara is Manu's cycle, the one who gives birth and governs the human race. Each Manu's life (Manvantara) consists of 71 Chaturyugas (quartets of Yugas or eras). Each Chaturyuga is composed of four eras or Yugas: Satya, Treta, Dwapara and Kali. Before and after each Manvantara there's a sandhikal as long as Krita Yuga and in that time there is all water on earth. The span of the Satya Yuga is 1,728,000 human years, Treta Yuga is 1,296,000 human years long, the Dwapara Yuga 864,000 human years and the Kali Yuga 432,000 human years. When Manu perishes at the end of his life, Brahma creates the next Manu and the cycle continues until all fourteen Manus and the Universe perish by the end of Brahma's day.
Space and time are considered to be Maya (illusion). What looks like 100 years in the cosmos of Brahma could be thousands of years in other worlds, millions of years in some other worlds and 311 trillion and 40 billion years for our solar system and earth. The life span of Lord Brahma, the creator, is 100 'Brahma-Years'. When 'night' falls, Brahma goes to sleep for a period of 4.32 billion years, which is a period of time equal to the day time (1 Kalpa) of Brahma and the lives of 14 Manus. The next 'morning', Brahma creates 14 additional Manus in sequence just as he has done on the previous 'day'. The cycle goes on for 100 'divine years' at the end of which Brahma perishes and is regenerated. Brahma's entire life equals 311 trillion and 40 billion years. Once a Brahma dies there is an equal period of un-manifestation for 311 trillion and 40 billion years, until the next Brahma is created. During one life of Brahma 504,000 Manus are changing.
The Rig Veda speculates about the origin of the cosmos:
"Neither being (sat) nor non-being was as yet. What was concealed? And where? And in whose protection?…Who really knows? Who can declare it? When was it born, and when came this creation? The devas were born later than this world's creation, so who knows from where it came into existence? None can know from where creation has arisen, and whether he has or has not produced it. He who surveys it in the highest heavens, He alone knows-or perhaps does not know." (Rig Veda 10. 129).
The Rig Veda's view of the cosmos also sees one true divine principle self-projecting as the divine word, Vaak, 'birthing' the cosmos that we know, from the monistic Hiranyagarbha or Golden Womb. The universe is considered to constantly expand since creation and disappear into a thin haze after billions of years. An alternate view is that the universe begins to contract after reaching its maximum expansion limits until it disappears into a fraction of a millimeter. The creation begins anew after billions of years (Solar years) of non-existence.
The Nasadiya Sukta of the Rig Veda describes the origin of the universe. The Rig Veda's view of the cosmos also sees one true divine principle self-projecting as the divine word, Vaak, 'birthing' the cosmos that we know, from the monistic Hiranyagarbha or Golden Egg. The Universe is preserved by Vishnu (The God of Preservation) and destroyed by Shiva (The God of Destruction). These three constitute the holy trinity (Trimurti) of the Hindu religion. Once the Universe has been destroyed by Shiva, Brahma starts the creation once again. This creation-destruction cycle repeats itself almost endlessly as described in the section above onBrahma, Manu and the Yugas.
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. At this point, Brahma rests for one night, just as long as the day. This process, named Pralaya, repeats for 100 Brahma years (36,000 days and 36,000 nights of Brahma; 311 trillion, 40 billion human years) that represent Brahma's lifespan as well as that of the universe. Shiva then destroys all existence while creating a new existence, and then time starts over. After Brahma's "death", it is necessary that another 100 Brahma years pass until he is reborn and the whole creation begins anew. This process is repeated ad infinitum.
Only some Puranas describe a universe that is cyclical or oscillating and infinite in time. The universe is described as a cosmic egg that cycles between expansion and total collapse. It expanded from a concentrated form — a point called a Bindu. The universe, as a living entity, is bound to the perpetual cycle of birth, death, and rebirth. The Padma Purana discusses the number of different types of life-forms in the universe. According to the Padma Purana, there are 8,400,000 life-form species, 900,000 of which are aquatic ones; 2,000,000 are trees and plants; 1,100,000 are small living insects species; 1,000,000 are birds; 3,000,000 are beasts and reptiles; and 400,000 are mammal species. In the Puranas, and before that in the Atharvaveda, there are fourteen worlds, seven higher ones (Vyahrtis) and seven lower ones (Pātālas), viz. 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 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. The 14 Lokas are: (1) Satya (2) Tapa (2) Jana (4) Mahar (5) Svar (6) Bhuvar (7) Bhu (8) Atala (9) Vitala (10) Sutala (11) Talatala (12) Mahatala (13) Rasatala (14) Patala. During each pralaya, the lower ten realms (loka) are destroyed while the higher four realms, including Satya-loka, Tapa-loka, Jana-loka, and Mahar-loka are preserved. During each Mahapralaya, all 14 realms are destroyed.
The concept of multiverses is mentioned many times in Puranic literature, such as in the Bhagavata Purana (400–1000 CE):
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)
After separating the different universes, the gigantic universal form of the Lord, which came out of the causal ocean, the place of appearance for the first puruṣa-avatāra, entered into each of the separate universes, desiring to lie on the created transcendental water (Bhagavata Purana 2.10.10).
The number of universes seems to be uncountable, immeasurable, or incalculable according to the Puranic literature:
Even though over a period of time I might count all the atoms of the universe, I could not count all of My opulences which I manifest within innumerable universes (Bhagavata Purana 11.16.39)
Analogies to describe multiple universes also exist in the Puranic literature:
What am I, a small creature measuring seven spans of my own hand? I am enclosed in a pot-like universe composed of material nature, the total material energy, false ego, ether, air, water and earth. And what is Your glory? Unlimited universes pass through the pores of Your body just as particles of dust pass through the openings of a screened window (Bhagavata Purana 10.14.11)
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)
Yoga Vashishtha, the text which states conversations between Vashistha, a Rig Vedic teacher, and various Gods and Kakbhusundi, a creature which stands outside of normal time and sees all. It recounts the cyclical nature of time, where Kakabhushundi has seen Ramayan 11 times with different outcomes and seen Mahabharat 16 times with different results, but, after seeing Daksha Yagya twice, he did not either care to see it again or saw no point to seeing any more, as it ended the same way each time. Further conversations talk about the atoms or anu at quantum level and inside each quantum level are different universes. A sorrowful queen is shown that her husband is still alive in one of the quantum or atomic universes and ruling wisely and is given the option to join him there. The idea of Heisenberg's Principle is enunciated when a Rishi visits and illustrates a decision tree by showing how several parallel universes, with all possible results of a decision, could occur and uses that illustration to explain why he took the decision he did in this universe.
Science writers Carl Sagan and Fritjof Capra have pointed out similarities between the latest scientific understanding of the age of the universe, and the Hindu concept of a "day and night of Brahma", which is much closer to the current known age of the universe than other creation views. The days and nights of Brahma posit a view of the universe that is divinely created, and is not strictly evolutionary, but an ongoing cycle of birth, death, and rebirth of the universe. According to Sagan:
The Hindu dharma 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 dharma 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.