Damage from the Heat Ray
The temperature at the center of the fireball generated by the atomic bomb at the moment of detonation was more than 1 million degrees Celcius. One second later, the fireball had grown to its maximum diameter of 280 meters. The fierce heat ray emitted from that fireball raised surface temperatures at the hypocenter to 3,000°C to 4000°C. (The surface temperature of the sun is 5,700°C; iron melts at 1500°C.)

●A Schoolgirl with Burns
August 10, 1945
Those exposed to the ferocious heat ray sustained serious burns. Skin exposed directly to the heat ray (with nothing to shield it) within roughly 1.2 kilometers of the hypocenter was burned to black char. Even internal organs were affected. Virtually everyone burned in this way died immediately or within a few days.

Photo: Hajime Miyatake
Courtesy: Asahi Shimbun
All rights reserved by the Asahi Shimbun.

●A man burned by the heat ray except where his waistband covered him
August 7, 1945
This man exposed within a kilometer of the hypocenter was critically burned over his whole body except where his waistband covered him.
Photo: Masami Onuka
●This woman's kimono pattern was burned into her skin.
Around August 15, 1945
Because dark colors absorb heat more readily than light colors, the heat ray burned the dark parts of this woman's kimono pattern into her skin.
Photo: Gon-ichi Kimura
●Road imprinted with the shadow of the bridge railing
Around November 1945
The heat ray scorched and blackened the asphalt, but it remained white where the bridge railing blocked the rays.
　 Photo: US Army