A radiation curve that combines the systematic effects of the precession of the equinoxes, the tilt of the earth's rotational axis, and the eccentricity of the earth's orbit. Early in the twentieth century, a Serbian mathematician and physicist, Milutin Milankovitch (1879–1958), calculated the composite solar radiation curve and used it to account for the variations of climate. He postulated that the effects of seasonal and latitudinal distribution of incoming solar radiation influenced climatic fluctuations of the order tens to hundreds of thousands of years, with each period of radiation minimum causing an ice age.