Book 5: Chapter 21
Srimad Bhagvata Mahapurana: Book 5: Chapter 21: Verses 1-11
Sri Suka began again : To this extent alone has the disposition of the terrestrial globe been described (by the learned) with (particular) reference to the extent and distinctive character of its parts. By (referring to) this (the extent of the terrestrial globe) the knowers of the subject (indirectly) describe the extent of the heavenly sphere as well, even as by referring to (the size of anyone of) the two halves of peas and other pulses (that of the other half is also made known). Between the two (heaven and earth) intervenes the sky (the aerial region), which is joined both to heaven (above) and earth (below). Placed at the centre of the sky, the glorious sun, the lord of the luminaries, warms by its heat and illuminates by its light (all) the three worlds (heaven, earth and the space lying between them). (Coursing) by slow, swift and regulated marches, known by the names of Uttarayana (the northerly march from the equator to the summer solstice and back to the equator), Daksinayana (the southerly march from the equator to the winter solstice and back to the equator) and the Vaisuvata (the march across the equator at the equinoxes) and rising higher (in the heavens), going down and taking a mean position whenever and wherever such positions are inevitable (under the divine law), the sun, while passing through the signs of the zodiac, from Makara (Capricornus) onwards, lengthens the days while shortening the nights and vice versa and brings their duration on a par. When the sun traverses the signs of Mesa (Aries) and Tula (Libra), the days and nights are (more or less) of equal length and when it traverses the five signs from Vrsabha (Taurus) onwards (viz., Vrsabha, Mithuna, Karkata. Sirnha and Kanya or Taurus, Gemini, Cancer, Leo and Virgo), days become longer and longer only while nights become shorter (on an average) by nearly half an hour (24 minutes) every month. (4) When (however) the sun traverses the five signs from Vrscika onwards (viz., Vrscika, Dhanus, Makara, Kumbha and Mina or Scorpio, Sagittarius, Capricornus, Aquarius and Pisces), days become shorter and nights (proportionately) longer. Days grow in length till the sun takes to the southward course and nights become longer and longer till it takes a northward turn. The learned declare the distance  covered by the revolution of the sun on the top of the (circular) Manasottara mountain as described heretofore (vide V. xx. 80) to be nine crore and fifty one lakh Yojanas (or seventy-six crore and eight lakh miles) and (further) mention the existence on that mountain of the city of Indra (the deity presiding over the eastern quarter), named Devadhani, the city of Yama (the deity presiding over the southern quarter), called Samyamani, the city of Varuna (the deity presiding over the western quarter), Nimlocani by name, and the city of Soma (the moon-god, the deity presiding over the northern quarter), known as Vibhavari, to the east, south, west and north respectively of Mount Meru. When the sun makes its way into these cities (one after another) at particular periods (of the day), there are on the four sides of Mount Meru sunrise, midday, sunset and midnight respectively-which serve as occasions for activity and suspension of activity on the part of living beings. For those dwelling on the Meru the sun ever shines as at midday. And though (actually moving in an easterly direction with its face turned towards the lunar mansions and) keeping the Meru on its left, it appears to (move in a westerly direction and) keep the Meru on its right (because of the movement in an opposite direction of the entire stellar sphere including the sun, which is going from east to west, being pushed by the wind known as Pravaha, which is always blowing with the Meru on its right).
It is a well-known fact that it sets (goes out of sight) just on the opposite side of the point where it rises (comes to view) and it sends the world to deep sleep (causes midnight) just opposite to the place where it torments people (by its heat), so as to make them drip with perspiration. (Similarly) they who clearly see it continually (from sunrise to sunset) no longer perceive it when it has gone to the other side (That is to say, when the sun shines overhead on the opposite side, there is midnight on this side). When the sun proceeds from the city of Indra to that of Yama, it traverses, in the course of fifteen Ghatikas (six hours), (a distance of) two and a quarter crore, twelve and a half lakh and more (twenty-five thousand) Yojanas (i.e., two crore, thirty-seven lakh and seventy-five thousand Yojanas all told or one-quarter of its total orbit). In the same way (in the same period) it travels from it (from the last-mentioned city, the city of Yama) to the city of Varuna, and (thence) to the city of Soma and (then) back to the city of Indra (all of which are situated at an equal distance from one another). So also other planets such as the moon alongwith the lunar mansions rise as well as set together in the stellar sphere.
- As the sun never remains at a fixed position according to the ancients and is constantly changing its course, turning more and more either towards the north or towards the south, days and nights are of equal duration, strictly speaking, only on two days in a year, viz., on the vernal and autumnal equinoxes. But the disparity in their length is very negligible during these two parts of the year, covering a total period of nearly two months, as it never exceeds 24 minutes. It is therefore that days and nights are spoken of as equal in length during this period. Similarly the length of days gradually increases and the length of nights is proportionately reduced only when the sun traverses the signs of Vrsabha and Mithuna; while during the other three months, viz., when the sun traverses the signs of Karkata, Simha and Kenya, the order is reversed, that is to say, the length of nights gradually increases and that of days diminishes. Days, however, nonetheless continue to be longer than nights till the sun takes to the southward course--- vide passage above. It is in this light that the statement in the latter part of passage above should be interpreted. And the statement made in passage above should also be construed likewise. Even so the monthly rate of fall in the duration of nights during the five months of the sun's northward course and in the length of days during the corresponding months of its southward course is not uniform every month; sometimes it exceeds 24 minutes, while at other times it is less than 24 minutes. 24 minutes should, therefore, be taken to be the average rate.
- By adding together half the diameter (fifty thousand Yojanas) of Jambudwipas-which lies at the centre of the lotus-like terrestrial globe----and the width of the five other circular Dwipas surrounding it, each of which is twice as large as the one preceding it, as well as of the six belts of oceans encircling the six Dwipas, each of which is equal in extent to the Dwipa enclosed by it, and joining to the total width of these six Dwipas and the same number of oceans surrounding them half the width of the seventh and largest Dwipa (Puskaradwipa) at the centre of which the mountain-belt called Manasottara is placed. the figure of one crore, fifty-seven lakh and fifty thousand Yojanas is arrived. This represents the radius of the circle described by the revolution of the sun's chariot on the top of the Manasottara mountain with Mount Meru, standing at the core of Jambudwipa, as its centre. The double of this number or 3 crore and fifteen lakh Yojanas represents the extent of its diameter. According to the established rules of geometry the extent of the circumference of a circle is 3 1/7 times as much as its diameter. Multiplying the length of the diameter as calculated above by 3 1/7 the figure comes to nine crore and ninety lakh Yojanas. This, however, does not tally with the figure cited in the text, which is 39,00,000 less. A learned commentator, however, points out that, really speaking, the distance from the centre of Mount Meru to the orb of the sun itself should be reckoned as +he radius of the circle and this has been ascertained from other authoritative sources to be in the neighbourhood of one crore and fifty-one lakh Yojanas only. Thus calculated, the diameter of the circle works out at the figure of three crore and two lakh Yojanas approximately. And by multiplying this figure by 3 1/7 the result arrived at exactly corresponds to the figure quoted in the text.