Early Theories on the Distance to the Sun
  According to an ancient Indian text (c. 1700 BC?), the heavens are 1000 earth diameters away from the earth. Other texts took the sun to be halfway to the heavens, so this suggests a distance of the sun about 500 earth diameters from the earth. The confirmation for this supposition comes from the later theories (c. 500 AD) from the same region and from Greek ideas that speak of roughly the same distance. We suggest that this original conception was transformed by the later Indian and Greek theories in different ways to deal with contradictory data related to outer planet periods. 
Subhash Kak