Prabhupāda: Just like progressive life, a child is progressing to youthhood, the youth is aspiring to become a big man, important man. As in this life there is progressive life, similarly, life after life, there is also progress. There are different grades of life. So we get information from authoritative books that there are 8,400,000's of different grades of life, and there are 900,000's of aquatic life, two million species of plants and trees, about eleven hundred thousand species of life of birds, three million types of species of beast, and 400,000 species of this human body. Out of that 400,000's, different kinds of human bodies, the civilized body is a great boon. At that time we can make further progress. Either we can transfer to
other planets... The standard of living, comforts, are many, many thousands times better than this planet. But in this book, Bhagavad-gītā As It Is, we get information that within this material universe, wherever you go, either you remain in this planet or you go to the moon planet or to the sun planet, or there are millions and trillions of planets... The highest planetary system is called Brahmaloka. There the duration of life is very, very great. You cannot calculate even twelve hours of their days. These are described in this book, Bhagavad-gītā As It Is. Sahasra-yuga-paryantam arhad yad brahmaṇo viduḥ (
BG 8.17). Four hundred... Three thousand years is the duration... Four hundred and, yes, four hundred and three thousands of years, solar years, is the one unit of yuga. Such thousand yugas makes twelve hours of the Brahmaloka planet. Similarly, they live there for a hundred years. But these four things, namely birth, death, old age, and disease, these four things are everywhere, either you live in this planet or moon planet or sun planet or any
other planet. The duration of life may be very, very great. Just like in comparison to the ant, our life, human being—we have got hundred years age—so to the ant it may be very astonishing: "Oh, how such a great length of time one can live?" Similarly, we may be astonished by hearing twelve hours duration of Brahmaloka, but actually there is. But still, you cannot avoid death. Death is there. So from this book we understand from the version of Kṛṣṇa, or God, that ā-brahma bhuvanāl lokāḥ punar āvartino 'rjuna (
BG 8.16). Even if you go to the highest planetary system, again you have to come back.