Editing Manhattan Project (section)

=== Bombings ===
On 6 August 1945, the ''[[Enola Gay]]'', a Boeing B-29 Superfortress of the 393d Bombardment Squadron, piloted by Tibbets, lifted off from North Field with a Little Boy in its bomb bay. Hiroshima, the headquarters of the [[2nd General Army]] and [[5th Division (Imperial Japanese Army)|Fifth Division]] and a port of embarkation, was the primary target, with Kokura and Nagasaki as alternatives. Parsons, the weaponeer in charge of the mission, completed the bomb assembly in the air to minimize the risks of a nuclear explosion in the event of a crash during takeoff.<ref>{{harvnb|Groves|1962|pp=315–319}}.</ref> The bomb detonated at an altitude of {{convert|1750|ft}} with a blast that was later estimated to be the equivalent of 13 kilotons of TNT.<ref>{{harvnb|Hoddeson|Henriksen|Meade|Westfall|1993|pp=392–393}}</ref> An area of approximately {{convert|4.7|sqmi|km2}} was destroyed. Japanese officials determined that 69% of Hiroshima's buildings were destroyed and another 6–7% damaged. Early estimates were that 66,000 people were killed and 69,000 injured; later re-estimations that included people ignored by previous methods, like Korean slave laborers and additional soldiers, concluded there might have been 140,000 dead from the attack by December 1945.<ref name="casualties">{{cite journal |last=Wellerstein |first=Alex |author-link=Alex Wellerstein |title=Counting the dead at Hiroshima and Nagasaki |journal=Bulletin of the Atomic Scientists |date=4 August 2020 |url=https://thebulletin.org/2020/08/counting-the-dead-at-hiroshima-and-nagasaki/ |access-date=23 January 2024}}</ref><ref name="USSBS">{{cite web |website=[[Harry S. Truman Presidential Library and Museum]] |title=U.S. Strategic Bombing Survey: The Effects of the Atomic Bombings of Hiroshima and Nagasaki |pages=9, 36 |date=19 June 1946 |url=http://www.trumanlibrary.org/whistlestop/study_collections/bomb/large/documents/pdfs/65.pdf |access-date=15 March 2009 |archive-date=31 January 2012 |archive-url=https://web.archive.org/web/20120131042336/http://www.trumanlibrary.org/whistlestop/study_collections/bomb/large/documents/pdfs/65.pdf |url-status=dead }}</ref><ref>{{cite web |url=http://www.readthespirit.com/ourvalues/life-arises-from-hiroshima-legacy-of-slavery-still-haunts-japan/ |title=Life Arises from Hiroshima: Legacy of slavery still haunts Japan |publisher=Our Values |first=Daniel |last=Buttry |access-date= 15 June 2016}}</ref><ref>{{cite web |url=http://www.hiroshimacommittee.org/Facts_NagasakiAndHiroshimaBombing.htm |title=Hiroshima and Nagasaki Bombing – Facts about the Atomic Bomb |publisher=Hiroshimacommittee.org |access-date=11 August 2013}}</ref>

[[File:Atomic bombing of Japan.jpg|thumb|left|The mushroom clouds of the atomic attacks on [[Hiroshima]], Japan, 6 August 1945 (left) and [[Nagasaki]], Japan, 9 August 1945 (right)|alt=Two mushroom clouds rise vertically.]]
On the morning of 9 August 1945, the ''[[Bockscar]]'',<!-- yes, it is "Bockscar" not "Bock's Car". This is ''not'' a typo! --> a second B-29 piloted by the 393d Bombardment Squadron's commander, Major [[Charles W. Sweeney]], lifted off with a Fat Man on board. This time, Ashworth served as weaponeer and Kokura was the primary target. When they reached Kokura, they found cloud cover had obscured the city, prohibiting the visual attack required by orders. After three runs and with fuel running low, they headed for the secondary target, Nagasaki. Ashworth decided that a radar approach would be used if the target was obscured, but a last-minute break in the clouds over Nagasaki allowed a visual approach as ordered. The Fat Man was dropped over the city's industrial valley midway between the Mitsubishi Steel and Arms Works in the south and the Mitsubishi-Urakami Ordnance Works in the north. The resulting explosion had a blast yield equivalent to 21 kilotons of TNT, roughly the same as the Trinity blast, but was confined to the [[Urakami]] Valley, and a major portion of the city, including the city center, was protected by the intervening hills. About 44% of the city was destroyed, and estimates of casualties range from 40,000 to 80,000 people killed and at least 60,000 injured.<ref>{{harvnb|Sklar|1984|pp=22–29}}</ref> Overall, an estimated 35,000–40,000 people were killed and 60,000 injured.<ref>{{harvnb|Groves|1962|pp=343–346}}.</ref><ref name="Hoddeson et al., pp. 396-397">{{harvnb|Hoddeson|Henriksen|Meade|Westfall|1993|pp=396–397}}</ref><ref name="casualties" />

Groves expected to have another atomic bomb ready for use on 19 August, with three more in September and a further three in October.<ref name="Briefing book-HullSeeman">{{cite web |title= Telephone conversation transcript, General Hull and Colonel Seeman (13 August 45) |publisher=George Washington University |date= 13 August 1945 |work=National Security Archive Electronic Briefing Book No. 162 |url= http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB162/72.pdf |access-date=23 January 2024}}</ref> Two more Fat Man assemblies were readied, and scheduled to leave [[Kirtland Air Force Base|Kirtland Field]] for Tinian on 11 and 14 August.<ref name="Hoddeson et al., pp. 396-397" /> At Los Alamos, technicians worked 24 hours straight to cast [[Demon core|another plutonium core]].<ref>{{cite web |url=http://manhattanprojectvoices.org/oral-histories/lawrence-litzs-interview-2012 |title=Lawrence Litz's Interview (2012) |publisher=Manhattan Project Voices |access-date=27 February 2015}}</ref> Although cast, it still needed to be pressed and coated, which would take until 16 August.<ref>{{cite web |url=http://blog.nuclearsecrecy.com/2013/08/16/the-third-cores-revenge/ |title=The Third Core's Revenge |publisher=Restricted Data |first=Alex |last=Wellerstein |author-link=Alex Wellerstein |date=16 August 2013 |access-date=27 February 2015}}</ref> It could therefore have been ready for use on 19 August.

On 10 August, Truman was informed that another bomb was being prepared. He ordered that no additional atomic bombs could be used without his express authority. According to [[Henry A. Wallace]], Truman told his cabinet that "the thought of wiping out another 100,000 people was too horrible. He didn't like the idea of killing, as he said, 'all those kids.'"<ref>{{harvnb|Wallace|1973|p=474}}</ref> Groves suspended the third core's shipment on 13 August.<ref name="Eclipsed by Hiroshima and Nagasaki">{{cite journal |title=Eclipsed by Hiroshima and Nagasaki: Early Thinking about Tactical Nuclear Weapons |first=Barton J. |last=Bernstein |author-link=Barton Bernstein |journal=[[International Security]] |issn=0162-2889 |volume=15 |issue=4 |date=Spring 1991 |pages=149–173 |jstor=2539014 }}</ref>

On 11 August, Groves phoned Warren with orders to organize a survey team to report on the damage and radioactivity at Hiroshima and Nagasaki as soon as the war ended. A party equipped with portable Geiger counters arrived in Hiroshima on 8 September headed by Farrell and Warren, with Japanese Rear Admiral Masao Tsuzuki, who acted as a translator. They remained in Hiroshima until 14 September and then surveyed Nagasaki from 19 September to 8 October.<ref>{{harvnb|Ahnfeldt|1966|pp=886–889}}.</ref> This and other scientific missions to Japan provided valuable data on the effects of the atomic bomb, and led to the creation of the [[Atomic Bomb Casualty Commission]].<ref>{{harvnb|Home|Low|1993|p=537}}.</ref>

In anticipation of the bombings, Groves had commissioned physicist [[Henry DeWolf Smyth]] to prepare a sanitized technical history of the project for public consumption. The idea of releasing such information freely was controversial; the decision to do so was made by Truman personally. The "[[Smyth Report]]" was released to the public on 12 August 1945.<ref>{{harvnb|Groves|1962|pp=348–362}}.</ref>

[[Surrender of Japan|Japan announced its surrender]] on 15 August.<ref>{{cite web|url=http://www.airforcemag.com/MagazineArchive/Pages/2012/August%202012/0812keeper.aspx |title=Hirohito's "Jewel Voice Broadcast" |work=Air Force Magazine |date=August 2012 |url-status=dead |archive-url=https://web.archive.org/web/20130910212019/http://www.airforcemag.com/MagazineArchive/Pages/2012/August%202012/0812keeper.aspx |archive-date=10 September 2013}}</ref> The necessity of the bombings became a [[debate over the atomic bombings of Hiroshima and Nagasaki|subject of controversy among historians]]. Some questioned whether "atomic diplomacy" would have attained the same goals, and the relative weight that the bombs and the [[Soviet–Japanese War (1945)|Soviet declaration of war]] had on the Japanese willingness to surrender.<ref name="Briefing book">{{cite web |last=Burr|first=William|title= The Atomic Bomb and the End of World War II, A Collection of Primary Sources |publisher=George Washington University |date= 13 August 1945 |work=National Security Archive Electronic Briefing Book No. 162 |url= http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB162/|access-date=23 January 2024}}</ref> The [[Franck Report]] was the most notable effort pushing for a demonstration but was turned down by the Interim Committee's scientific panel.<ref>{{harvnb|Frisch|1970|pp=107–115}}.</ref> The [[Szilárd petition]], drafted in July 1945 and signed by dozens of scientists working on the Manhattan Project, was a late attempt at warning Truman about his responsibility in using such weapons.<ref>{{harvnb|Hewlett|Anderson|1962|pp=399–400}}.</ref><ref>{{cite web |url=http://www.trumanlibrary.org/whistlestop/study_collections/bomb/large/documents/index.php?documentdate=17%20July%201945&documentid=79&studycollectionid=abomb&pagenumber=1 |title=Petition to the President of the United States, 17 July 1945. Miscellaneous Historical Documents Collection |publisher=[[Harry S. Truman Presidential Library and Museum]] |access-date=20 October 2012 |archive-date=18 May 2015 |archive-url=https://web.archive.org/web/20150518092746/http://www.trumanlibrary.org/whistlestop/study_collections/bomb/large/documents/index.php?documentdate=17%20July%201945&documentid=79&studycollectionid=abomb&pagenumber=1 |url-status=dead }}</ref>