Although it is not in our experience, there is a milk ocean within this universe. Even the modern scientist accepts that there are hundreds and hundreds of thousands of planets hovering over our heads, and each of them has different kinds of climatic conditions. Srimad-Bhagavatam gives much information which may not tally with our present experience. But as far as Indian sages are concerned, knowledge is received from the Vedic literatures, and the authorities accept without any hesitation that we should look through the pages of authentic books of knowledge (sastra-caksurvat). So we cannot deny the existence of the ocean of milk as stated in the Srimad-Bhagavatam unless and until we have experimentally seen all the planets hovering in space. Since such an experiment is not possible, naturally we have to accept the statement of Srimad-Bhagavatam as it is because it is so accepted by spiritual leaders like Sridhara Svami, Jiva Gosvami, Visvanatha Cakravarti and others. The Vedic process is to follow in the footsteps of great authorities, and that is the only process for knowing that which is beyond our imagination.