So this is evolution. This evolution theory . . . it is not theory, it is fact stated in the Vedic literature, Padma Purāṇa, how we have passed through so many bodies, and ultimately we have got this civilized human form of body. We have to pass through 900,000 forms of aquatic body within the water. Then gradually we come to the form of trees and plants. There are two million varieties. Then we get the bodies of the insect. There are 900,000 forms of body. Then we enter into the species of birds, one million forms of body. Then after bird's body, there are three million different varieties of beasts' body. Then after this period, we become human body, but there are 400,000 species of human body. And thus we get this nice human form body, with good brain and good consciousness. So it should be utilized properly. By the laws of nature—prakṛteḥ kriyamāṇāni guṇaiḥ karmāṇi sarvaśaḥ (BG 3.27), this is the law of nature—gradually we develop different types of body and different types of consciousness. So when we come finally to God consciousness, or Kṛṣṇa consciousness, that is the perfection of life.
So we are living in this planet, but in other planets also there are different forms of life. So there is one planet . . . there are many millions of planet. Specifically, there is one planet within this universe that is called Siddhaloka. There is other planet also, heavenly planet, Brahmaloka planet, and in different planets there are different species of life, different standard of comforts, but in the higher planetary system, the standard of comfort is more and more, thousand times more, thousand times more, in this way. Just like in this planet we have got different standard of life. In your Western countries your standard of life is . . . at least, it is to be understood more comfortable than other standard of life. In this way, if you promote yourself to the topmost planetary system, which is called Brahmaloka, then you get your duration of life many millions of years. It is stated in the Bhagavad-gītā that sahasra-yuga-paryantam ahar yad brahmaṇo viduḥ (BG 8.17). In the Brahmaloka planet, the residents, they have got their one day. One day means daytime, not nighttime, twelve hours, say. That is equal to . . . their twelve hours is equal to our millions of years, sahasra-yuga. Sahasra-yuga means forty-three hundred thousands of years multiplied by one thousand. That is called sahasra-yuga. Such is the . . . the such duration of time is equal to twelve hours in the Brahmaloka planet. So even if you go to the Brahmaloka planet . . . (aside) You read that, ā-brahma-bhuvanāl lokāḥ punar āvartino 'rjuna. Read it.