āste tūṣṇīṁ dinātyaye
This verse is an explanation of the night of Brahmā, which is the effect of the influence of time in touch with an insignificant portion of the modes of material nature in darkness. The dissolution of the three worlds is effected by the incarnation of darkness, Rudra, represented by the fire of eternal time which blazes over the three worlds. These three worlds are known as Bhūḥ, Bhuvaḥ and Svaḥ (Pātāla, Martya and Svarga). The innumerable living entities merge into that dissolution, which appears to be the dropping of the curtain of the scene of the Supreme Lord’s energy, and so everything becomes silent.