Atomic Bombs and Their Impact

Overview

This lecture reviews the development, use, and aftermath of atomic bombs on Hiroshima and Nagasaki in August 1945, and examines their impact on World War II, the nuclear age, and ongoing debates about nuclear weapons and energy.

Historical Context

• By the early 20th century, Japan and the USA competed for power and resources in the Asia-Pacific.
• Japan's expansion included Korea, Taiwan, parts of China, and Southeast Asia.
• The Second Sino-Japanese War began in 1937, including atrocities like the Nanjing Massacre.
• In response, the US imposed an oil embargo on Japan in 1940.
• Japan attacked Pearl Harbor in 1941, bringing the US into WWII; Japan joined Axis powers.

Development and Use of Atomic Bombs

• The US developed atomic bombs with uranium and plutonium through the Manhattan Project, involving Hanford (plutonium), Oak Ridge (uranium), and Los Alamos (development).
• The first atomic bomb test (Trinity Test) occurred on July 16, 1945.
• The Potsdam Declaration issued an ultimatum for Japan’s surrender, threatening total destruction.

Hiroshima and Nagasaki Bombings

• Hiroshima was bombed on August 6, 1945, with "Little Boy" (uranium bomb) for its military significance and undamaged state.
• The bomb caused immense destruction, firestorms, and immediate and long-term casualties.
• Nagasaki was bombed on August 9, 1945, with a more powerful plutonium bomb after the original target, Kokura, was obscured by fog.
• Japan announced its surrender on August 15; formal surrender was signed on September 2, 1945.

Consequences and Legacy

• Estimated deaths by the end of 1945: 110,000–210,000, plus long-term victims from radiation.
• Survivors faced societal discrimination and ongoing disputes about state compensation and recognition.
• The bombings marked the start of the atomic age and the Cold War arms race.
• Subsequent nuclear tests increased global nuclear fears and influenced culture (e.g., Godzilla).
• Postwar Japan relied heavily on nuclear energy until the 2011 Fukushima disaster prompted renewed protests and policy changes.

Key Terms & Definitions

• Atomic bomb — A weapon that uses nuclear fission to release massive destructive energy.
• Manhattan Project — The US-led program to develop atomic bombs during WWII.
• Potsdam Declaration — Ultimatum issued to Japan demanding unconditional surrender.
• Trinity Test — The first detonation of a nuclear device.
• Cold War — The geopolitical tension primarily between the US and Soviet Union after WWII.

Action Items / Next Steps

• Review the causes and consequences of WWII’s use of nuclear weapons.
• Reflect on the ongoing debates about nuclear weapons and energy for class discussion.