Matsya Purana — Solar–Lunar Motions
विदूरभावादर्कस्य भूमेरेषा गतस्य च श्रयन्ते रश्मयो यस्मात् तेन रात्रौ न दृश्यते //
vidūrabhāvādarkasya bhūmereṣā gatasya ca śrayante raśmayo yasmāt tena rātrau na dṛśyate //
Because the Sun is far away, and because it has moved to the other side of the Earth, its rays fall and rest elsewhere; therefore it is not seen at night.
This verse is not about pralaya; it gives a cosmological explanation for night—when the Sun is positioned away from our side of the Earth, its rays illuminate elsewhere, so it is not visible.
Indirectly, it supports dharma through right knowledge (tattva/jñāna): understanding time (day/night) underlies proper scheduling of royal administration and household rites that are prescribed for specific times.
Ritually, it implies why many rites are time-bound—certain acts are prescribed for daytime when sunlight is present, while night has distinct observances; it does not give specific Vastu rules but supports the time-science behind ritual timing.