dIpAvali f. a row of lights , nocturnal illumination BhP. iv , 21 , 4 , also = {dIpAdI} -valiprayoga} m. N. of wk. at one time in the distant past, our ancestors lived in the Arctic region (the polar region). In this region, darkness prevailed for six months. The sun appeared on Mesha Sankranthi day (the sun entering the Aries sign of the Zodiac). The sun sets in this region on Tula Sankranthi day (when the sun enters Libra). During the movement between these two regions, there is an interval of six months. http://www.dailynews.lk/2007/11/08/fea09.asp