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Bhuu and its many related words and expressions are linked to the root earth in Sanskrit.
Vedic mythology and Vedic astronomy describes Bhu-mandala, Bhuloka to be divided into 7 islands ( planets in outer space). It is said that Maharaja Priyavrata drove his celestial chariot behind the sun, the rims of his chariot wheels created impressions that later became seven oceans, dividing the planetary system known as Bhu-mandala into seven islands. So, he created seven different types of oceans and planetary systems, which altogether are known as Bhu-mandala, or Bhuloka.
Each island is surrounded by a liquid substance, beyond which is the next island. Each island is twice as large as the one preceding it. All the 7 islands are completely surrounded by the 7 oceans, and each ocean is equal in breadth to the island it surrounds. The names of 7 islands and 7 rulers of them (sons of Maharaja Priyavrata) and 7 oceans are:
- 1st island: Jambu: Agnidhra,
- 1st ocean: salt water,
- 2nd island: Plaksa: Idhmajihva,
- 2nd ocean: sugarcane juice,
- 3rd island: Salmali: Yajnabahu,
- 3rd ocean: liquor,
- 4th island: Kusa: Hiranyareta,
- 4th ocean: clarified butter,
- 5th island: Kraunca: Ghrtaprstha,
- 5th ocean: milk,
- 6th island: Saka: Medhatithi,
- 6th ocean: emulsified yogurt,
- 7th island: Puskara: Vitihotra,
- 7th ocean: sweet drinking water.
According to Viraraghava Acarya, the breadth of the first island is 100,000 yojanas. One yojana equals eight miles, and therefore the breadth of the first island is calculated to be 800,000 miles.
Bhagavat Purana (Srimad Bhagavatam, BBT Edition) Author: A.C. Bhaktivedanta Swami