Śrīmad-Bhāgavatam · Text 3.11.22
Who is speaking and story frame
त्रिलोक्या युगसाहस्रं बहिराब्रह्मणो दिनम् ।
तावत्येव निशा तात यन्निमीलति विश्वसृक् ॥ २२ ॥
tri-lokyā yuga-sāhasraṁ
bahir ābrahmaṇo dinam
tāvaty eva niśā tāta
yan nimīlati viśva-sṛk
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.
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