Within this one universe, there are fourteen planetary systems, and the living entities are wandering in different bodily forms on different planets. According to karma, the living entity sometimes goes up and sometimes goes down. The lower systems are called Bhurloka, the middle systems are called Bhuvarloka, and the higher planetary systems, up to Brahmaloka, the highest planetary system of the universe, are called Svarloka. And all of them are situated on the body of the Lord. In other words, no one within this universe is without a relationship with the Lord. Modern enterprisers (the astronauts who travel in space) may take information from Srimad- Bhagavatam that in space there are fourteen divisions of planetary systems. The situation is calculated from the earthly planetary system, which is called Bhurloka. Above Bhurloka is Bhuvarloka, and the topmost planetary system is called Satyaloka. These are the upper seven lokas, or planetary systems. And similarly, there are seven lower planetary systems, known as Atala, Vitala, Sutala, Talatala, Mahatala, Rasatala and Patala lokas. All these planetary systems are scattered over the complete universe, which occupies an area of two billion times two billion square miles. The modern astronauts can travel only a few thousand miles away from the earth, and therefore their attempt to travel in the sky is something like child’s play on the shore of an expansive ocean. The moon is situated in the third status of the upper planetary system. There are innumerable universes beyond the one in which we are put, and all these material universes cover only an insignificant portion of the spiritual sky. The entire material universe is called Devidhama, and above it there is Sivadhama, where Lord Siva and his wife Parvati eternally reside. Above that planetary system is the spiritual sky where innumerable spiritual planets, known as Vaikunthas, are situated. Above these Vaikuntha planets there is Kṛṣṇa’s planet known as Goloka. Goloka Vrndavana is larger than all the material and spiritual planets put together. Those who are devotees of the Narayana expansion of Kṛṣṇa attain the Vaikuntha planets, but it is very difficult to reach Goloka Vrndavana. Indeed, that planet can be reached only by persons who are devotees of Lord Caitanya or Lord Sri Kṛṣṇa.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Second Canto, Chapter 5 – Text 38, 40 & 41
A.C. Bhaktivedanta Swami Prabhupada (2012 edition), “Teachings of Lord Caitanya, The Golden Avatara”, Page 168,
A.C. Bhaktivedanta Swami Prabhupada (2007 edition), “Teachings of Lord Kapila, The Son of Devahuti”, Page 15