the Decision to Drop the Atomic Bombs on Hiroshima and Nagasaki,
Atomic Bombing of
Hiroshima, Japan-August 6, 1945
August 2, 1939: Albert Einstein sends a letter to President
Roosevelt describing the feasibility of atomic power, the potential
use of atomic bombs, and a warning that Germany is already working on
March 28, 1941: American
scientists conclude that plutonium can be used as a weapon.
December 6, 1941:President Roosevelt
authorizes the Manhattan Project to develop atomic weapons.
December 7, 1941:Japanese forces attack the
Unites States Naval base at Pearl Harbor, Hawaii, thus bringing the
United States into World War Two.
December 2, 1942:Enrico Fermi and his team at the University of
Chicago produce the world’s first controlled and sustained
nuclear fission reaction.
March, 1943:Construction begins on The
Hanford Site, in Washington State.
1944: A second uranium reactor is built at
Clinton, Tennessee for manufacturing plutonium for an atomic bomb.
(The first reactor was Fermi’s experiment in Chicago).
November, 1944: The first batch of
plutonium from Hanford's reactors is ready for testing.
January, 1945: Weaponizaton of plutonium
begins at Hanford with the reprocessing of th plutonium.
January 20, 1945: The first batch of
Uranium-235 is successfully separated at Oak Ridge National
April 12, 1945: President Franklin D.
S Truman, becomes the 33rd President of the United
States.As Roosevelt had
never bothered to inform Truman of the Manhattan Project or anything
about the atomic bomb program, Truman spent his first couple of weeks
as President completely unaware of the atom bombs currently in
April 24, 1945: Secretary of War Harry
Stimson and General Leslie Groves (who was the general in charge of
the Manhattan Project), brief President Truman on the full scope of
the atomic research and development and the plans for the atomic
April 27, 1945: The Target
Committee meets for the first time in order to
decide which Japanese cities to target with the atomic bomb.
May 8, 1945:Germany surrenders to the
Allies, ending the war in Europe.
June 22, 1945: The Battle of Okinawa ended
after 82 bloody days. Okinawa is an island (part of Japan itself),
and the Japanese military and the civilian population on the island
fought ferociously. Allied casualties (dead, wounded, and missing),
equalled 82,000. Over 360 Allied ships were damaged in the battle,
largely due to the suicide Kamikaze plane attacks, while 768 U.S.
warplanes were lost. Most of the Japanese defenders literally fought
to the death, and even most of the civilian population chose to die
rather than surrender. The heavy Allied casualties, combined with the
ferocity shown by the Japanese in defending home territiory, was a
major consideration in President Truman's decision to use the atomic
bombs. Plans were already underway for an Allied invasion of the main
Japanese Home Islands, and based on the defense of Okinawa, estimates
of Allied casualties ranged from 250,000 to nearly a million. It was
known that the Japanese were preparing to defend the Home Islands,
and that millions of civilians were being trained to fight as
July 16, 1945:The Trinity test
explosion of the world’s first atomic bomb occurred at
Alamogordo, New Mexico. The bomb exploded with force equivalent to
fifteen thousand tons of dynamite, and the flash of light could be
seen over 200 miles away.The
test explosion was more powerful than expected by the scientists and
military personnel working in the Manhattan Project.
1945:The USS Indianapolis, a U.S. Navy Heavy
San Francisco, carrying parts and the enriched uranium (about half of
the world's supply of Uranium-235 at the time) for the Little
Boy atomic bomb with orders to deliver the cargo to the Pacific
island of Tinian.
July 21, 1945: Truman, who was in Potsdam, Germany at a conference with the
leaders of Britain and the Soviet Union, receives his first full
report on the Trinity Test. Over the course of the next couple of
weeks, Truman would meet with Generals Marshall and Eisenhower, as
well as with British Prime Minister Winston Churchill regarding this
July 26, 1945: The Potsdam Declaration, calling for
the unconditional surrender of Japan, is issued by the United States,
Britain, and China. While not specifying that the U.S. now had atomic
weapons, the Declaration asserted that unless Japan surrendered, it
would face "prompt and utter destruction.”The
Japanese government chose to respond with silence.
26, 1945:The USS Indianapolis, a U.S. Navy Heavy Cruiser,
arrived at the island of Tinian.
July 30, 1945:After
delivering the atomic cargo to Tinian, The
USS Indianapolis was returning to the U.S., when it was struck
by a torpedo fired by the Imperial Japanese Navy submarine
I-58, sinking in 12 minutes. Of 1,196 crewmen aboard the
Indianapolis, approximately 300 went down with the ship. The
900 crewmen who survived the sinking faced exposure, dehydration,
saltwater poisoning, and shark attacks while floating in the ocean
with few lifeboats and almost no food or water. The Navy learned of
the sinking when survivors were spotted four days later by the crew
of a patrol plane. Only 317 of the sailors survived. This attack
resulted in the greatest single loss of life at sea in the history of
the U.S. Navy.
6, 1945: The Enola Gay, a
B-29 Superfortress bomber based on the Pacific island of Tinian, and
commanded by Colonel Paul Tibbets, drops a 15 kiloton atomic bomb
nicknamed Little Boy over the Japanese city of Hiroshima.
Approximatley 130,000 people died in the explosion and the immediate
after-effects of the attack.
9, 1945: Per earlier agreements
between Stalin, Churchill, and Roosevelt at Yalta, the Soviet Union
declared war on Japan and launched a massive invasion of
Japanese-held China (the Manchuria region), northern Korea, Sakhalin
Island, and the Kurile Islands.
9, 1945:Bockscar, aB-29
Superfortress commanded by Major Charles Sweeney, dropped a 21
kiloton atomic bomb on the Japanese city of Nagasaki.The original target was the city of Kokura, but bad weather and the
smoke from massive bombing raid from the day before, obscured the
target area, forcing Bockscar to divert to the secondary
target of Nagasaki.Roughly 60,000-70,000 died in this atomic attack.
Atomic Bombing of
Nagasaki, Japan-August 9, 1945
10, 1945: Japanese Emperor Hirohito
decides that Japan must accept the Potsdam Declaration and surrender.
14-15, 1945: Attempted coup in Japan
with the intention of continuing the war.The coup attempt took place the night before Japan was to
announce the surrender.The
coup failed, and Japan announced acceptance of the Potsdam
Declaration and their surrender to the Allies.
15, 1945: In arecorded radio address, Emperor Hirohito
announced to his people and to the world that Japan would surrender
to the Allies.
September 2, 1945: Aboard the USS Missouri, an American
battleship in Tokyo Bay, representatives of the Japanese government
signed the official documents of surrender.World War Two thus ended.