Rig Veda divides the universe into three regions – bhurloka (the Earth), bhuvarloka (the Firmament) and svarloka (the Heaven). This division was later extended to seven in the Hindu Puranas by introducing Maharloka (abode of sages), Jnanaloka (abode of sons of Brahma), Tapaloka (abode of deities) and Satyaloka (abode of Brahma). Bhurloka is described as being round in shape by Vedic seers in Aitareya Brahmana. In Vedic Samhitas, it is personified as the mother of all beings, and is invoked together with the sky.
Puranas and astronomical texts like Surya Siddhanta (400
CE), describe the genesis of bhurloka in detail. These texts state that the
Supreme Power first created water (apa) and deposited energy in matter. This
transformed itself into Hiranyagarbha (a golden spherical egg) which was
enveloped in darkness. Quite in the middle of the egg, the bhurloka stands in
akasha. The golden mount and the holy mount Meru, having a collection of
manifold jewels, pass through the middle of Bhurloka and is called jambudvipa.
The great ocean girdling divides bhurloka into two hemispheres – of the gods
and the demons. Six mountain ranges running east and west intersect at the
jambudvipa. The regions lying between them are called varsha (clime). In the quadrant
of the Earth’s circumference, Bhadrashva lies to the East. To the South is the
Bharatavarsha, in which Lanka is situated. To the West is the Ketumala, in
which the city of Romaka is situated. Northward lies Uttarakuru, the land of the
perfect beings.