Śrīmad-Bhāgavatam 3.11.20
SB 3.11.20
Open the full passageSanskrit
sandhyā-sandhyāṁśayor antar yaḥ kālaḥ śata-saṅkhyayoḥ tam evāhur yugaṁ taj-jñā yatra dharmo vidhīyate
Translation
The transitional periods before and after every millennium, which are a few hundred years as aforementioned, are known as yuga-sandhyās, or the conjunctions of two millenniums, according to the expert astronomers. In those periods all kinds of religious activities are performed.