Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v1.c5.40

v1.c5.40

The questions above about the sun as having disturbed the primitive mind is not merely a figment of fancy. Evidence of such primitive thought is found in the Jain literature which shows that the Jains believed in the existence of two suns. The Purāṇas too have postulated twelve different suns for the twelve months of the year. The twelve Ādityas of the Vedic literature are also well known. Although these notions appear today to be fantastic, it is clear that there was a time when people really cherished such beliefs. For instance the following verse from the Rigveda would show that the sun was supposed to have actually sunk itself in ocean before rising the next day.