Before the Bombing
Before 1942
- 1938: Nuclear fission is discovered in Germany. Scientists realize it could be used to make extremely powerful weapons.
- August 1939: Albert Einstein and Leo Szilard write a letter to President Roosevelt warning that Nazi Germany might build an atomic bomb.
- 1942: The United States launches the Manhattan Project, a secret program to develop nuclear weapons.
1945: The Final Stage of WWII
- July 16: The first nuclear test, called the Trinity Test, is successfully conducted in New Mexico, USA.
- July 17 – August 2: The Potsdam Conference is held. The U.S., U.K., and Soviet Union demand Japan’s unconditional surrender.
- July 26: The Potsdam Declaration is issued. Japan ignores it.
August 6, 1945: The Bombing of Hiroshima (Minute-by-Minute)
| Time (JST) | Event |
|---|---|
| 02:45 | The B-29 bomber Enola Gay takes off from Tinian Island, carrying the bomb “Little Boy.” |
| 06:07 | Japanese radar detects a B-29 scout plane near Hiroshima, but it is not considered a threat. The air raid warning is lifted. |
| 07:09 | Another brief air raid warning is issued, then canceled. People return to their normal routines. |
| 08:09 | Enola Gay reaches Hiroshima. Weather is clear, so the mission proceeds. |
| 08:15:17 | The atomic bomb is dropped from an altitude of 9,400 meters (about 31,000 feet). |
| 08:16:02 | “Little Boy” explodes 600 meters above the city, near Aioi Bridge. The temperature at the center reaches 3,000–4,000°C. |
Minutes After the Explosion
| Time | Event |
|---|---|
| 08:16–08:20 | The city center is completely destroyed. About 80% of people within 1.5 km of the blast die instantly. Fires break out all over the city. |
| 08:20–09:00 | Survivors begin escaping to the rivers. Many have severe burns and hanging skin. Communication lines are cut. |
| 09:00 and later | Government and military officials try to respond, but leadership is in chaos. Injured people flee to the outskirts. |
| Noon–Evening | A radioactive “black rain” begins to fall. Rescue teams enter the city but are exposed to radiation. |
Nagasaki & the End of the War
| Date | Event |
|---|---|
| August 9, 11:02 | A second bomb, “Fat Man,” is dropped on Nagasaki, killing about 74,000 people. |
| August 15 | Emperor Hirohito announces Japan’s unconditional surrender in the famous Gyokuon Broadcast. World War II ends. |
Aftermath and Long-Term Effects
| Period | Event |
|---|---|
| By the end of 1945 | About 140,000 people in Hiroshima and 74,000 in Nagasaki die. Many die from radiation. |
| From 1946 onward | Survivors begin to suffer from radiation effects like cancer, leukemia, infertility, and birth defects. |
| 1957 | Japan enacts a law to provide medical aid to atomic bomb survivors (hibakusha). |
| From the 1980s | Survivors begin sharing their stories. Peace museums and testimony programs are launched. |
| Today | Around 110,000 hibakusha are still alive, most over 80 years old. The memory of the bombings is passed on to future generations. |
Key Terms to Know
- Manhattan Project: U.S. project to develop nuclear weapons.
- Little Boy / Fat Man: Names of the bombs dropped on Hiroshima and Nagasaki.
- Potsdam Declaration: Statement demanding Japan’s surrender.
- Gyokuon Broadcast: Emperor’s radio speech announcing the end of the war.
- Hibakusha: Atomic bomb survivors.
- Black Rain: Rain containing radioactive particles that fell after the explosion.
