On a flat-earth model, the sun must be localized, otherwise it would be impossible to have the variations of light during the day. According to the Book of Enoch, the sun is localized, and according to Srfmad Bhiigavatam 5 .21.7, the sun is said to move over a flat area of land with its localized rays creating sunrise, midday, sunset and midnight. The great iiciiry a and authority on Vedic cosmology, Sri:la VisvanathaCakravarti Thakura, explains the sun moving over a flat-earth as follows:
Amongst the four directions around Meru, wherever the sun is seen to rise, it is noon in the varsa (tract of land) to the east, midnight to the varsa in the west, and sunset in the varsa to the north. And when it is noon, it is sunset in the eastern varsa, sunrise in the western varsa and midnight in the northern varsa. When one sees sunset, it is noon in the western varsa, midnight in the eastern varsa and sunrise in the northern varsa. All the people situated in all the varsas consider themselves situated to the south of Meru and simply see sunrise, noon and sunset in their own var$a, and know the events of the sun in other varsas by the previously mentioned conception.
Vishnu Puran reference to Flat Earth Model
In the Visnu Purana it is said:
Situated in one city, the sun touches three other cities and two intermediate places. Situated at an intercardinal city, the sun touches three intercardinal cities and two cardinal cities. Situated in any of the cardinal cities, the sun touches three cardinal directions and two intercardinal directions. Situated in the eastern var$a at noon, there is sun rise in the southern varsa, sunset in the northern varsa. This is the meaning of touching three cardinal directions. (SB:Commentary 5.21.8-9 translation by H.H Bhanu Swami)
The idea of a cardinal direction has meaning on a flat plane but gives no reference to the "up" direction. Thus, all explanations given herein refer to a flat plane of land. As the sun's radiation illuminates all lands in the universe, the explanation of the way the sun moves over Jambudvipa or the demigods' abode is also applicable to our abode called earth.
Is our Sun Localized
The sun always rotates clockwise over a flat circular island, beginning Eastward and ending in the Westward. Wherever the sun is overhead, that place experiences midday. As there are always four time-periods current at any one time, the place that is diametrically opposite to the sun at midday experiences midnight (SB: 5.21.9). Similarly, the place to the right (counterclockwise) of the sun at midday experiences evening, while the place to the left (clockwise) experiences morning. The expanse of the sun's rays includes the shades of light pertaining to morning, midday, and evening. The fading light is due to the forward moving sun and its chariot of light having a limited expanse, and, being seen at a distance, the sun looks to be disappearing on the horizon of one's vision. This can only happen on an island that is not moving, if the sun is localized, and if the sun's light has a limited reach.
As a person stands at any position (looking toward the center of the island) and experiences the sun above at midday, the place to his right has already seen the sun and must therefore be experiencing evening going toward night. However, when the person standing at one position is experiencing the sun on the horizon (sunrise) that same right-hand direction is experiencing
midday. In this way,the directions are given with the middle of a circle being north and the outside being south. In this case, the place to the right (while one faces inward toward the north) is East (where the sun comes from), and the place to the left is West (where the sun moves toward).
Visvanatha Chakravarti said:
It is stated in the Visnu Purana that sarvesam dvipavar$anam merurut taratah sthitah: all the inhabitants have Meru in the north (relatively speaking). (SB.Commentary 5.21.8-9) They can have Meru in the north only if Meru is in the center, and the earth they live on is flat with the sun circurnambulating above in a clockwise direction.