A tenth of a millisecond later, all of the materials that had made up the bomb converted into an ionized gas, and electromagnetic waves were released into the air. The thermal heat of the bomb ignited a fireball with an internal temperature of over 540,000 degrees Fahrenheit. Within one second, the blazing fireball expanded from 52 feet to its maximum size of 750 feet in diameter. Within three seconds, the ground below reached an estimated 5,400 to 7,200 degrees Fahrenheit. Directly beneath the bomb, infrared heat rays instantly carbonized human and animal flesh and vaporized internal organs.
