Uranium bomb dropped on hiroshima exploded at eight 16 a m 18 hundred and 70 feet above the ground, only 550 feet wide of its aiming point. The nuclear chain reaction it triggered created a corpes temperature of about one million degrees cels, s igniting the air around it to a diameter of nearly a kilometer. Thermal and ionizing radiation killed virtually all people within a kilometer of the surface of the fire ball, burning them to death or rupturing their internal organs. Farther out, in successive consen i circles around the epi center, people were exposed to gamma rays, neutron radiation, flash burns. Street cars were lifted from their tracks and