Regarding details of the universe, be satisfied by reading only Bhagavatam. What is the use of reading other books - you are not going there. Some portion of the earth is flat. When you stand in any place you see flat, so for us to some extent it appears flat, but it is round.
Simply keep faith that whatever we describe, that is a fact. After all, we are an insignificant creature in the universe, so whether you take the modern scientists or Sukadeva Goswami, it is inconceivable. It is best to keep faith in Sukadeva Goswami, because actually our only business is to go back to home, back to Godhead. So whether Sukadeva Goswami or the modern scientists are right or wrong, it is nothing interesting to us. We want to go back to home, back to Godhead - yanti mad-yajino'pi mam.
Letter to Madhava, 3 October, 1976