Śrīmad-Bhāgavatam 3.11.22
SB 3.11.22
Open the full passageSanskrit
tri-lokyā yuga-sāhasraṁ bahir ābrahmaṇo dinam tāvaty eva niśā tāta yan nimīlati viśva-sṛk
Translation
Outside of the three planetary systems [Svarga, Martya and Pātāla], the four yugas multiplied by one thousand comprise one day on the planet of Brahmā. A similar period comprises a night of Brahmā, in which the creator of the universe goes to sleep.