devanam oka asit svar
bhutanam ca bhuvah padam
martyadinam ca bhur lokah
siddhanam tritayat param
Heaven was established as the residence of the demigods, Bhuvarloka as that of the ghostly spirits, and the earth system as the place of human beings and other mortal creatures. Those mystics who strive for liberation are promoted beyond these three divisions.
Planets such as Indraloka and Candraloka are meant for the heavenly enjoyment of the most pious fruitive workers. The highest four planets, however, Satyaloka, Maharloka, Janoloka and Tapoloka, are meant for those who are most perfectly endeavoring for liberation. Caitanya Mahaprabhu is so inconceivably merciful that He is promoting the most fallen victims of Kali-yuga beyond these four planets and even beyond Vaikuntha, to the supreme planet of Lord Krsna in the spiritual sky, called Goloka Vrndavana. Srila Bhaktisiddhanta Sarasvati Thakura explains that heaven is the residence of the demigods, the earth is the residence of the human beings, and in between is a temporary residence for both classes of beings.