> > ((4/3) * pi * 1738)/((4/3) * pi * 6378) = 27% > > Am I crazy or am I right? > > Vitaliy I don't think you are crazy, you just forgot to cube the radius (1738/6378)**3 = 0.0202 John -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist