Vishnupurana 2.8.p6

2.8.p6

When the sun is in the cities of Sakra and others, the three cities and two intermediate points are illuminated; and when he is in an intermediate point he extends light to the two cities and three intermediate points. From the time of his rising till midday the rays of the sun gradually increase; and from then he moves towards setting with his diminishing rays. By the rising and the setting of the sun the east and west quarters are ascertained. As far as the sun shines in front so far he shines behind, and thus on both the sides illuminating all the places except the court of Brahmā which is situate on the summit of Meru—the mountain of the celestials. When the rays of the sun reach the court of Brahmā they are repelled and driven back by the radiance which prevails there. Consequently there is the alternation of day and night in northern quarter in as much as all the insular continents are situated on the north of Meru.