Codename "Little Boy", the first atomic weapon used in war was dropped on Hiroshima from the B-29 Enola Gay, on this day August 6th 1945. This and the bombing of the city of Nagasaki three days later effectively brought an end to WW2.
Hiroshima CloudReleased at 08:15 local time (11:15 GMT), the bomb took 57 seconds to fall from the aircraft to the detonation height 600 meters above the city, where it exploded with the force of approximately 15,000 tons of TNT. The temperatures directly beneath the fireball were instantaneously raised to approximately 4000c vaporising anyone exposed.
Birds burst into flames mid-flight, and combustible materials such as paper ignited as far away as 2km from ground zero. The white light acted as a giant flashbulb, burning the dark patterns of clothing onto skin and the shadows of bodies onto walls. Flash burns
Total destruction extended to 1.6 km, with resulting fires across 13 kmē. The Blast and heat directly killed an estimated 70,000 people, destroyed approximately 69% of the city's buildings and severely damaged another 6.6%. In the following months, an estimated 60,000 more people died from their injuries, and hundreds more from radiation.
Japan did not respond to further calls for their surrender, and three days later the atomic bomb was used again on the city of Nagasaki, followed shortly by their capitulation and the end of World War II. The decision use nuclear weapons against the cities of Hiroshima and Nagasaki remains a highly controversial issue to this day, and is one that belies simple analysis. However some of the following factors should be considered:-
The invasion of Japan would have without doubt resulted in massive casualties on both sides as the Japanese had shown their resolve to defend their land without mercy or quarter, demonstrated by the massive loss of life at the battle of Iwo Jima.
Truman did not want to be in a position after the war where he had to explain why he had a means to end the war swiftly but did not use it, especially one that had cost such a vast amount of money ($23billion USD 2007 adjusted).
There was undeniably a strong hatred of the Japanese at that time, due in no small part to Japan's wartime conduct, with the use of chemical and biological weapons, appalling ill treatment of POW's and other war crimes.
Curtis LeMayThe atomic bombings were truly horrific and caused massive loss of life but need to be considered in the context of the ongoing campaign by the US Strategic Air Command led by Curtis LeMay, to bomb Japan into submission with conventional ordnance.
Fleets of B-29s dropped thousands of incendiary bombs creating fire storms that would destroy entire cities in a night. One such attack on Tokyo turned the city into a solid sheet of fire destroying 16 square miles and incinerating over 100,000 men women and children.
By late summer almost a hundred Japanese cities had been reduced to ashes. However both Hiroshima and Nagasaki were kept "off limits", so that the full effects of the new bomb could be observed on "virgin" targets.
Another highly influential factor was that the USSR had just declared war on Japan. It was in the US's best interest to finish the war quickly so as to exclude the Soviets the from post-war land negotiations. The Soviets also made no secret of the fact that they wished to bring Communism to the rest of Europe. Demonstrating both the power of this weapon, and the US's resolve to use it was probably instrumental in preventing their advance into the rest of Europe.
sonicbomb Forum Admin
Joined: Aug 06, 2006
Tue Aug 07, 2007 3:23 pm
Posted on behalf of Fastfissions post of the front page
The stats on the Tokyo firebombings using conventional weapons make interesting reading. Couple of points. The strapline says April instead of August. Also, according to the 2hr Hiroshima documentary shown again on The History Channel (UK) last night, the bomb took 43 seconds to fall, not 57. Not sure which figure is right. Whilst I posted a similar question on Tsar's forum, I still find wonder why Los Alamos never bothered to test Little Boy, only Fat Man. They must have been really sure of their physics to make the untested weapon, the first to be deployed on the battlefield..... Anyway, happy birthday Little Boy. The party certainly went with a bang! (groan).
sonicbomb Forum Admin
Joined: Aug 06, 2006
Tue Aug 07, 2007 3:24 pm
Based on Tsars post on this subject on the old forums
Little Boy was used first was because the Trinity test used most, if not all, of the avaliable weaponizable plutonium at the time. Little Boy was ready to be deployed by August 1st (10th lastest). Fatman would not be ready until August 6th (a second Fatman bomb by August 24th). Only one Little Boy bomb was built at the time, while many Fatman casings were ready. The only issue was the plutonium, which was made just prior to the Nagasaki mission.
The theory of implosion was proven to be successful during Trinity, however, I doubt the planners thought the Fatman bomb was 'full-proof' as a weapon. Fatman was much safer then Little Boy, because in order for an implosion bomb to work, you truly need a deliberate initiation of the explosives assembly. This also makes the bomb more complex. So I would assume that the preparations of turning the Trinity Gadget into a deployable weapon took alot of time. Even right before loading Fatman onto 'Bock's Car', crude sealing was applied to the casing to protect the delicate barometric switch which detonated the bomb.
At the end of the day, it's all speculative.
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