Hans Bethe, who discovered the violent force behind sunlight, helped devise the atom bomb and eventually cried out against the military excesses of the cold war, died late Sunday. He was 98, among the last of the giants who inaugurated the nuclear age. His death was announced by Cornell University, where he worked and taught for 70 years. A spokesman said he died quietly at home. Except for the war years at Los Alamos, N.M., Dr. Bethe lived in Ithaca, N.Y., an unpretentious man of uncommon gifts. His students called him Hans and admired his muddy shoes as much as...