The Atom BombInventing to Incinerate

The Debate

- By spring 1945, it was clear that Japan was not going to surrender to the Allies.

- An invasion was being planned by the Allies to conquer Japan.

- This would’ve resulted in massive loss of life; anywhere between 500,000-1 million-plus (or more) Allied soldiers and even more Japanese soldiers and citizens.

Invasion?

- In a letter sent to Gen. Curtis LeMay from Gen. Lauris Norstad when LeMay assumed command of the B-29 force on Guam, Norstad told LeMay that if an invasion took place, it would cost the US "half a million" dead.

- A study done for Secretary of War Henry Stimson's staff estimated that conquering Japan would cost 1.7–4 million American casualties, including 400,000–800,000 fatalities, and five to ten million Japanese fatalities. The key assumption was large-scale participation by civilians in the defense of Japan.

- Other estimates fell in between these numbers.

What Could’ve Been

Developing the Bomb

• In 1939, Albert Einstein wrote to FDR, suggesting Germany might build an incredibly powerful bomb, and urging the USA to build it before the Nazis.

• Scientists had succeeded in splitting a uranium atom; to make a bomb they had to succeed in creating a chain reaction.

• In theory, this would lead to a massive release of energy.

The Manhattan Project

• Determined to build the bomb before Hitler, FDR organized the MANHATTAN PROJECT, a top-secret plan to develop the atomic bomb.

• Composed of top nuclear physicists and scientists.• 1942: ENRICO FERMI produced a controlled chain

reaction in a laboratory at the University of Chicago.• Scientists began working on designing a bomb that

could store more material and trigger a gigantic reaction on demand.

TESTING the bomb

• In July 1945, Manhattan Project scientists tested the first atom bomb in the New Mexico desert.

• Test explosion, called “TRINITY,” blew a huge crater in the ground and shattered windows 125 miles away.

• Oppenheimer: “Now I am become death, destroyer of worlds.”

The Decision• With the bomb ready, the question was whether or not to

use it.• Alternatives to its use included:– Invasion of Japan (and the massive casualties it would bring)– A naval blockade to starve Japan, combined with

conventional (non-atomic) bombing– A demonstration of the bomb on a deserted island to scare

Japan into surrender– A softening of demands on the Japanese for its unconditional

surrender.

The Decision (Cont’d)• President Harry Truman’s advisors, called the

INTERIM COMMITTEE, had met in the spring of 1945, before the Trinity test, to discuss the alternatives.

• It could not recommend any. • Allies had already taken heavy casualties in Pacific

fighting, especially at Iwo Jima and Japanese island of Okinawa.

• Final authority ultimately rested with Truman.

Truman’s Conscience• Truman took over as president after FDR died in

April 1945.• Had no difficulty deciding to drop the bomb.– Considered the bomb a military weapon and had no

doubt that it should be used.– Never regretted the decision– 1963: “You should do your weeping at Pearl Harbor.”

- Truman to critics

Dropping the Bomb• August 6, 1945: American plane, the

Enola Gay, drops a single bomb on the Japanese city of Hiroshima.– Military target: Hiroshima was the site of

large military base.– 80,000 died; at least that many injured.– 90% of city’s buildings were destroyed.

• “Wherever you went, you didn’t bother to take the roads. Everything was flat, nothing was standing — no gates, pillars, walls, or fences. You walked in a straight line to where you wanted to go. Practically everywhere you came across small bones that had been left behind.”

– Hiroshima survivor

No Surrender• Japan did not surrender immediately despite the

awesome destructive power of America’s newest weapon.

• Three days later, a second bomb was dropped on Nagasaki.– Major industrial center; site of major port, as well as

shipbuilding and aircraft construction.– 80,000 dead

V-J DAY• 3 days after the second atomic bomb was dropped,

Japan accepted the American terms for surrender, setting off a wave of celebration across the USA.

• Formal surrender occurred aboard the battleship USS Missouri in Tokyo Bay on September 2, 1945. The war was officially over.