Encyclopedia of India–China Cultural Contacts v1.c6.19

v1.c6.19

As for movements of the sun and moon, many translated *sutras* mention that they moved around Mt Sumeru propelled by the wind wheel. The height of the solar and lunar orbital motions is half of Mt Sumeru, ie 42,000 yojanas. The diameter of sun was 51 yojanas, and of the moon 50 yojanas. The sun moved around Mt Sumeru Mountain, day and night causing alterations and seasonal changes in the four continents. In *Li shi a pi tan lun* (*Treatise on Creating the World of Abhidharma*), the Chapter 19 of Volume 5 entitled ‘Motion of the Sun and the Moon’ mentions that there are 180 paths for the solar movement and 15 paths for the lunar movement. In half-a-year, the sun transits from one solar path to the next consecutively each day and after reaching the outermost it returns to the innermost solar path. This model helps better explain the changes in the time of sunrise azimuth and the length of day. As far as the lunar path is concerned, each lunar path is equal to 12 solar paths. The distance between the outermost (southernmost) and innermost (northernmost) path of the 180 solar paths is 290 yojanas. The sun and moon travel their next successive path on each day. The centre of illumination of sunlight is a ball with the diameter of 721,200 yojanas.