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.