Universe is created by God Brahma.

According to Indian mythologies, the span of life of the universe, which is known by the name of Kalp consists of 4320000000 human years, has been divided into 1000 epochs or Chaturyugas. Each Chaturyug is made up of four Yugas or ages, viz Satya, Treta, Dvapar, and Kali.

Satyayug - 1728000 years
Treta - 1296000 years
Dvapar - 864000 years
Kaliyuga - 432000 years

Thus, the duration of Dvapar is twice that of Kaliyug, that of Treta thrice and Satyayug four times that of Kaliyug.

The Universe is divided into fourteen spheres, seven higher and seven lower. In their ascending order the seven higher spheres are named as Bhuh, Bhuvah, Svah, Mahah, Janah, Tapah, and Satyam; while the lower seven are in their descending order named as Atal, Vital, Sutal, Talatal, Mahatal, Rasatal and Patal.

The tree of universe
Lord Vishnu is considered the tree of universe who has its roots in the unmanifested Brahma and has existed from timed without beginning.

It has four states of consciousness, viz, waking life, dream, sound sleep, and the pure impersonal state. These are called four barks.

The six states of existence, viz, to be, to come into being, to undergo transformation, to grow, to decay and to perish, are six stems.

The twenty-five categories of which this world of matter is composed of, viz, Prakriti or Primordial matter, Mahat or Cosmic Reason, Ahankar or the Cosmic Ego-sense, Manas or the Cosmic Mind, Chitta or the Cosmic Intellect, the five senses of perception, viz, the senses of hearing, touch, sight, taste and smell, the five subtle elements (tanmatras) and five Mahabhutas are the twenty-five boughs; the countless latent desires are the numberless leaves, the numerous acts of volition to attain such desires are the abundant flowers, pleasure and pain are the twofold fruit and Maya (Cosmic Illusion) is the creeper that clings to this tree of the universe.