The material world is only one fourth of the Supreme Personality of Godhead’s creation, but it is unlimited and impossible for anyone to know or describe, even with the qualification of a life as long as that of Brahmā, who lives for millions and millions of years. Modern scientists and astronomers try to explain the cosmic situation and the vastness of space, and some of them believe that all the glittering stars are different suns. From Bhagavad-gītā, however, we understand that all these stars (nakṣatras) are like the moon, in that they reflect the sunshine. They are not independent luminaries. Bhūloka is explained to be that portion of outer space through which the heat and light of the sun extend. Therefore it is natural to conclude that this universe extends in space as far as we can see and encompasses the glittering stars. Śrīla Śukadeva Gosvāmī admitted that to give full details of this expansive material universe would be impossible, but nevertheless he wanted to give the King as much knowledge as he had received through the paramparā system. We should conclude that if one cannot comprehend the material expansions of the Supreme Personality of Godhead, one certainly cannot estimate the expansiveness of the spiritual world. The Brahma-saṁhitā (5.33) confirms this:
advaitam acyutam anādim ananta-rūpam
ādyaṁ purāṇa-puruṣaṁ nava-yauvanaṁ ca
The limits of the expansions of Govinda, the Supreme Personality of Godhead, cannot be estimated by anyone, even a person as perfect as Brahmā, not to speak of tiny scientists whose senses and instruments are all imperfect and who cannot give us information of even this one universe. We should therefore be satisfied with the information obtainable from Vedic sources as spoken by authorities like Śukadeva Gosvāmī.