Lord Kṛṣṇa instructs that all the planets within the material universe are destroyed at the end of 4,300,000 x 1,000 x 2 x 30 x 12 x 100 solar years. And all the living beings inhabiting these material planets are destroyed materially along with the destruction of the material worlds. The living entity, however, is constitutionally an anti-material particle. But unless he elevates himself to the region of the anti-material worlds by cultivation of anti-material activities, he is destroyed materially at the annihilation of the material worlds and is subject to take rebirth in a material shape with the rebirth of a new material universe. In other words, he is subject to the pains of repeated birth and death. Only those living entities who take to the loving service of the Personality of Godhead during the manifested stage of material life are undoubtedly transferred to the anti-material worlds after quitting the material body. Immortality is obtained only by those who return to Godhead by practice of anti-material activities.
What are these anti-material activities? They are medicines. For example, when a man falls ill, he goes to a physician who prescribes medicines which eventually cure the suffering patient. Similarly, the materialist is ailing, and he should consult an expert transcendentalist-physician. What is his ailment? He is suffering the tribulations of repeated births, deaths, diseases and old age. Once he agrees to put himself under the "back to Godhead" treatment, he is able to transfer himself to the anti-material world, where there is eternal life instead of birth and death.
Annihilation of the material world takes place in two ways. Partial annihilation occurs at the end of every 4,300,000 x 1,000 solar years, or at the end of each day of Brahmaloka, which is the topmost planet in the material world. During that time of partial annihilation, the topmost planets such as Brahmaloka are not annihilated, but at the end of each duration of 4,300,000 x 1,000 x 2 x 30 x 12 x 100 solar years, the entire cosmic manifestation is merged into the anti-material body from whence the material principles emanate, manifest and merge after annihilation. The anti-material world, which is far removed from the material sky, is never annihilated. It absorbs the material world. It may be that a "clash" occurs between the material and anti-material worlds, as suggested by the scientists, and that the material worlds are destroyed, but there is no annihilation of the anti-material worlds. The eternally existing anti-material world is unmanifested to the material scientist. He can simply have information of it insofar as the principles of its existence are contrary to the modes of the material world. Full details of the anti-material universe can be known only from the infallible source of liberated authorities who have thoroughly realized the constitution of the anti-material principle. This information is received by aural reception by a submissive disciple of the Personality of Godhead.
The Vedic knowledge was thus imparted unto the heart of Brahmā, the first living being in the material creation. It was Brahmā who related this knowledge to the sage Nārada Muni. Similarly, the Bhagavad-gītā was spoken by the Personality of Godhead, Śrī Kṛṣṇa, to Vivasvān, the presiding deity of the sun, and when the aural chain of disciplic succession was broken, Lord Kṛṣṇa repeated the Bhagavad-gītā to Arjuna on the Battlefield of Kurukṣetra. At that time, Arjuna took the role of disciple and student in order to receive transcendental knowledge from Śrī Kṛṣṇa. In order to drive out all misgivings which the gross materialists of the world may have, Arjuna asked all relevant questions, and the answers were given by Kṛṣṇa so that any layman can understand them. Only those who are captivated by the glamour of the material world cannot accept the authority of Lord Śrī Kṛṣṇa. One has to become thoroughly clean in habit and heart before one can understand the details of the anti-material world. Bhakti-yoga is a detailed scientific transcendental activity that both the neophyte and the perfect yogī can practice.
The material world is only a shadow representation of the anti-material world, and intelligent men who are clean in heart and habit will be able to learn, in a nutshell, all the details of the anti-material world from the text of the Bhagavad-gītā, and these are in actuality more exhaustive than material details. The basic details are as follows:
The presiding Deity of the anti-material world is Śrī Kṛṣṇa, who exists in His original personality as well as in His many plenary expansions. This personality and His plenary expansions can be known only by anti-material activities commonly known as bhakti-yoga, or devotional service. The Personality of Godhead is the supreme truth, and He is the whole anti-material principle. The material principle as well as the anti-material principle is an emanation from His person. He is the root of the complete tree. When water is poured onto the root of a tree, the branches and leaves are nourished automatically. And in the same way, when Śrī Kṛṣṇa, the Personality of Godhead, is worshiped, all details of the material worlds are enlightened, and the heart of the devotee is nourished without his having to work in a materialistic way. This is the secret of the Bhagavad-gītā.
The process of entering into the anti-material worlds differs from materialistic processes. The individual living being can very easily enter the anti-material world by practicing anti-material activities while residing in the material world. But those who are truly gross materialists, who depend on the limited strength of experimental thought, mental speculation and materialistic science, find great difficulty in entering the anti-material worlds. The gross materialist may try to approach the anti-material worlds by endeavoring with spaceships, satellites, rockets, etc., which he throws into outer space, but by such means he cannot even approach the material planets in the higher regions of the material sky, and what to speak of those planets situated in the anti-material sky, which is far beyond the material universe. Even the yogīs who have perfectly controlled mystic powers have great difficulty entering into that region. Master yogīs who control the anti-material particle within the material body by practice of mystic powers can give up their material bodies at will at a certain opportune moment and can thus enter the anti-material worlds through a specific thoroughfare which connects the material and anti-material worlds. If they are at all able, they act in accordance with the prescribed method given in the Bhagavad-gītā:
Those who have realized the Transcendence can reach the anti-material world by leaving their material bodies during the period of uttarāyana, that is, when the sun is on its northern path, or during auspicious moments in which the deities of fire and effulgence control the atmosphere.
The different deities, or powerful directing officers, are appointed to act in the administration of cosmic activities. Foolish people who are unable to see the intricacies of cosmic management laugh at the idea of personal management of fire, air, electricity, days, nights, etc., by demigods. But the perfect yogīs know how to satisfy these unseen administrators of material affairs and, taking advantage of the good will of these administrators, leave their material bodies at will during opportune moments arranged for entrance into the anti-material universe or into the highest planets of the material sky. In the higher planets of the material world, the yogīs can enjoy more comfortable and more pleasant lives for hundreds of thousands of years, but life in those higher planets is not eternal. Those who desire eternal life enter into the anti-material universe through mystic powers at certain opportune moments created by the demigod-administrators of cosmic affairs, administrators unseen by the gross materialists who reside on this seventh-class planet called "Earth."
Those who are not yogīs but who die at an opportune moment due to pious acts of sacrifice, charity, penance, etc., can rise to the higher planets after death, but are subject to return to this planet (Earth). Their going forth takes place at a period known as dhūma, the dark, moonless half of the month, or when the sun is on its southern path.
In summary, the Bhagavad-gītā recommends that one adopt the means of devotional service, or anti-material activities, if one wishes to enter the anti-material world. Those who adopt the means of devotional service, as prescribed by the expert transcendentalist, are never disappointed in their attempts to enter the anti-material world. Although the obstacles are many, the devotees of Lord Kṛṣṇa can easily overcome them by rigidly following the path outlined by the transcendental devotees. Such devotees, who are passengers progressing in the journey of life toward the anti-material kingdom of God, are never bewildered. No one is cheated or disappointed when he adopts the guaranteed path of devotion for entrance into the anti-material universe. One can easily attain all the results that are derived from the studies of the Vedas, performances of sacrifice, practices of penance and offerings of charities simply by the unilateral performance of devotional service, technically known as bhakti-yoga.