Matsya Purana — Dhruva as Cosmic Pivot: Motions of Sun–Moon–Planets
यो ऽसौ चतुर्दशर्क्षेषु शिशुमारो व्यवस्थितः उत्तानपादपुत्रो ऽसौ मेढीभूतो ध्रुवो दिवि //
yo 'sau caturdaśarkṣeṣu śiśumāro vyavasthitaḥ uttānapādaputro 'sau meḍhībhūto dhruvo divi //
That celestial Śiśumāra (the cosmic dolphin-form) stationed amid the fourteen nakṣatras is Dhruva, the son of Uttānapāda, fixed in the heavens as the pivot-post—the cosmic axle about which all revolves.
It does not describe Pralaya directly; it presents the stable cosmic order after creation—Dhruva as the fixed pivot in the heavens around which the stellar arrangement (Śiśumāra) is conceived.
Indirectly, it models dhruvatā—steadfastness and stability: just as Dhruva is the fixed pivot of the heavens, the ideal king/householder should be firm in dharma, becoming a stabilizing center for society and family.
No explicit Vāstu or temple rule is stated, but the idea of a 'pivot/axis' (meḍhī) supports ritual-cosmological mapping: temples and altars are often aligned to a central axis (brahmasthāna/axis mundi) reflecting a stable cosmic center like Dhruva.