According to Hindu cosmology. Universe contains 7 upper and 7 lower planetary systems.
In the Puranas and in the Atharvaveda, there are fourteen worlds, seven higher ones (Vyahrtis) and seven lower ones (Patalas), viz. bhu, bhuvas, svar, mahas, janas, tapas, and satya above and atala, vitala, sutala, rasātala, talātala, mahātala, patala and naraka below.
The concept of a loka or lokas develops in the Vedic literature. Influenced by the special connotations that a word for space might have for a nomadic people, loka in the Veda did not simply mean place or world, but had a positive valuation: it was a place or position of religious or psychological interest with a special value of function of its own.
Hence, inherent in the ‘loka’ concept in the earliest literature was a double aspect; that is, coexistent with spatiality was a religious or soteriological meaning, which could exist independent of a spatial notion, an ‘immaterial’ significance. The most common cosmological conception of lokas in the Veda was that of the trailokya or triple world: three worlds consisting of earth, atmosphere or sky, and heaven, making up the universe.