The perfect yogī then determines where he is to go. There are innumerable material planets, and beyond these planets there is the spiritual world. Yogīs have this information from Vedic scriptures. For example, before I came to the United States I read descriptions of it from books. Similarly, a description of the higher planets and the spiritual world can be found in the Vedic scriptures. The yogī knows everything; he can transfer himself to any planet he likes. He does not need the help of spacecraft.
Material scientists have been trying for many years, and they will go on trying for one hundred or one thousand years more, but they will never reach any planet. Maybe by a scientific process one or two men can reach some planet, but that is not the general process. The generally accepted process for transferral to other planets is the practice of the yoga system or the jñāna system. The bhakti system, however, is not meant for transferral to any material planet. Those who engage in the devotional service of Kṛṣṇa, or the Supreme Lord, are not interested in any of the planets of this material world because they know that no matter to which planet one elevates himself, he will still find the four principles of material existence there nonetheless. On some planets the duration of life is much longer than on this earth, but death is there. Those who are Kṛṣṇa conscious, however, transcend this material life of birth, death, disease and old age.
Spiritual life means release from this botheration and misery. Those who are intelligent, therefore, do not try to elevate themselves to any planet of this material world. Men are trying to reach the moon, and although it is very difficult to gain entrance to that planet, if we do gain entrance the period of our lives will be enhanced. Of course, that does not apply to life in this body. If we were to enter the moon with this body, instant death would be certain.
When one enters into a planetary system, he must have a suitable body for that planet. Every planet is inhabited by living entities with bodies suitable for that planet. For instance, we can enter the water in this body, but we cannot live there. We may stay there fifteen or sixteen hours, or maybe twenty-four hours, but that's all. Aquatic animals, however, have particular bodies suitable for living their whole lives in water. Similarly, if one takes a fish out of water and puts it on the land, it will die instantly. As we understand that even on this planet there are different kinds of bodies for living in particular places, so, similarly, if we want to enter another planet, we have to prepare ourselves to get a suitable body.
If one transfers himself and his soul transmigrates to the moon by this yogic process, he gets a long duration of life. On the higher planets, six of our months equal one day. Thus the beings there live for ten thousand years. That is the description in the Vedic literature. So undoubtedly one can get a very long duration of life, but still there is death. After ten thousand or twenty thousand years, or even after millions of years (it does not matter), death comes.
Actually, we are not subject to death. That is affirmed in the beginning of Bhagavad-gītā (2.20): na hanyate hanyamāne śarīre. We are spirit soul, and therefore we are eternal. Why then should we subject ourselves to death and birth? It is intelligent to think in this way. Those who are Kṛṣṇa conscious are very intelligent because they are not interested in getting promotion to any planet where there is death, despite a long duration of life there. Rather, they want to get a body like God's. Īśvaraḥ paramaḥ kṛṣṇaḥ sac-cid-ānanda-vigrahaḥ. (Bs. 5.1) God's body is sac-cid-ānanda. Sat means "eternal," and cit means "full of knowledge." Ānanda means "full of pleasure."
As stated in our pamphlet Kṛṣṇa, the Reservoir of Pleasure, if we transfer ourselves to the spiritual world, to Kṛṣṇa's planet or to any other spiritual planet, then we will get a body similar to God's: sac-cid-ānanda—eternal, full of knowledge and full of bliss. So those who try to be Kṛṣṇa conscious have a different aim of life than those who are trying to promote themselves to the better planets in this material world. Lord Kṛṣṇa says, mūrdhny ādhāyātmanaḥ prāṇam āsthito yoga-dhāraṇām: "The perfection of yoga is to transfer oneself to the spiritual world." (BG 8.12)
The spirit soul is a minute particle within the body. We cannot see it. One practices the yoga system to raise the soul to the topmost part of the head. This practice goes on while one is living, and the perfection is reached when one can place himself on the top of the head and then break through. Then he can transfer himself to whatever higher planets he likes. That is the perfection of the yogī.