#Hiroshima : #OnThisDay

On 6th of August 1945 the USA detonated an atomic bomb over the Japanese city of Hiroshima.

The consent of the United Kingdom was obtained for the bombing, as was required by the Quebec Agreement, and orders were issued on 25 July by General Thomas Handy, the acting chief of staff of the United States Army, for atomic bombs to be used against Hiroshima, Kokura, Niigata, and Nagasaki.

At the time of the attack, the population of Hiroshima was approximately 340,000–350,000.

At 08:09, Tibbets started his bomb run and handed control over to his bombardier, Major Thomas Ferebee. The release at 08:15 (Hiroshima time) went as planned, and the Little Boy containing about 64 kg (141 lb) of uranium-235 took 44.4 seconds to fall from the aircraft flying at about 9,400 meters (31,000 ft) to a detonation height of about 580 meters (1,900 ft) above the city. Enola Gay was 18.5 km (11.5 mi) away before it felt the shock waves from the blast.

Due to crosswind, the bomb missed the aiming point, the Aioi Bridge, by approximately 240 m (800 ft) and detonated directly over Shima Surgical Clinic.

 It released the equivalent energy of 16 ± 2 kilotons of TNT (66.9 ± 8.4 TJ). The weapon was considered very inefficient, with only 1.7 percent of its material fissioning.

The radius of total destruction was about 1.6 kilometres (1 mi), with resulting fires across 11 km² (4.4 sq mi).

Enola Gay stayed over the target area for two minutes and was 16 kilometres (10 mi) away when the bomb detonated. Only Tibbets, Parsons, and Ferebee knew of the nature of the weapon; the others on the bomber were only told to expect a blinding flash and given black goggles.

“It was hard to believe what we saw”, Tibbets told reporters, while Parsons said “the whole thing was tremendous and awe-inspiring … the men aboard with me gasped ‘My God’.” He and Tibbets compared the shockwave to “a close burst of ack-ack fire”

The exact number of people killed by the blast, firestorm, and radiation effects of the bombing are unknown. Estimates have ranged from 66,000 people killed and 69,000 injured, upwards to 140,000 dead (by December 1945) in later estimations.

Over 90 percent of the doctors and 93 percent of the nurses in Hiroshima were killed or injured—most had been in the downtown area which received the greatest damage.