Srimad Bhagavatam — Tritiya Skandha, Shloka 20
Kāla-vibhāga: The Divisions of Time from Atom to Brahmā, and the Lord Beyond Time
सन्ध्यासन्ध्यांशयोरन्तर्य: काल: शतसंख्ययो: । तमेवाहुर्युगं तज्ज्ञा यत्र धर्मो विधीयते ॥ २० ॥
sandhyā-sandhyāṁśayor antar yaḥ kālaḥ śata-saṅkhyayoḥ tam evāhur yugaṁ taj-jñā yatra dharmo vidhīyate
每个时代之前与之后的过渡期，如前所述为数百年，精通天文者称之为“瑜伽-桑迪亚”（时代交会）。在这些时期，各类宗教与法行得以施行。
FAQs
In Canto 3, Chapter 11, this verse explains that the interval between sandhyā and its fractional portion (sandhyā-aṁśa) is counted in hundreds of units, and learned authorities designate such measured spans as part of yuga-based time reckoning.
The verse defines yuga not only as a time-measure but as an age in which dharma is arranged and manifested in a particular way—implying that moral and spiritual order is understood in relation to cosmic time cycles.
It encourages aligning one’s daily discipline (dharma) with regular “junctions” and rhythms—using transitions (like dawn/dusk) for prayer, reflection, and recommitment to spiritual practice.