Hiroshima atomic bomb: The US nuclear attack that changed history

As Japan marks 74th anniversary of world's first nuclear bomb attack, we examine the events that shaped history.

    Hiroshima atomic bomb: The US nuclear attack that changed history
    Hiroshima after atomic bomb attack in 1945 [Prisma Bildagentur/Getty Images]

    Japan has marked 74 years since a US atomic bomb attack that razed the city of Hiroshima to the ground at the end of World War II.

    Around 50,000 people, including representatives from around the world, attended on Tuesday a ceremony held in the Peace Memorial Park near ground zero to honour the memory of the victims of the world's first nuclear bomb attack.

    In a speech, Hiroshima Mayor Kazumi Matsui called on the international community to work towards a world without atomic weapons.

    Below we take a look at the events that shaped the course of history.

    What happened in Hiroshima? 

    On August 6, 1945, at about 8:15am Japanese time, the US aircraft Enola Gay dropped an untested uranium-235 gun-assembly bomb nicknamed "Little Boy" over Hiroshima. 

    The devastation was unlike anything in the history of warfare, ushering in the era of weapons of mass destruction.

    Hiroshima was immediately flattened. The resulting explosion killed 70,000 people instantly; by December 1945, the death toll had risen to some 140,000.

    The radius of total destruction was reportedly 1.6km.


    "The impact of the bomb was so terrific that practically all living things - human and animal - were literally seared to death by the tremendous heat and pressure set up by the blast," Tokyo radio said in the aftermath of the explosion, according to a report by The Guardian in August 1945.

    "All the dead and injured were burned beyond recognition. Those outdoors were burned to death, while those indoors were killed by the indescribable pressure and heat."

    But the damage did not end there. The radiation released from the explosion caused further suffering.

    Thousands more died from their injuries, radiation sickness and cancer in the years that followed, bringing the toll closer to 200,000, according to the Department of Energy's history of the Manhattan Project. 

    Why did the US drop the bomb?

    Japan was a fierce enemy of the US and its allies, Britain, China and the Soviet Union during World War II. 

    By 1945, the allies had turned the tide of the war and pushed the Japanese forces back from many locations.

    The Japanese had publicly stated their intent to fight to the bitter end, and were using tactics such as kamikaze attacks, in which pilots would suicide dive against US warships. 

    In July 1945, US President Harry Truman and allies demanded the "immediate and unconditional" surrender of Japan, but Japan did not issue a clear response.

    Shortly after, the US attacked Hiroshima, which was seen as a strategically sound target due to weather conditions, aircraft range, military impact and morale impact upon the enemy.


    "What has been done is the greatest achievement of organised science in history. It was done under high pressure and without failure," Truman said 16 hours after the atomic bomb was dropped

    "We are now prepared to obliterate more rapidly and completely every productive enterprise the Japanese have above ground in any city. We shall destroy their docks, their factories, and their communications. Let there be no mistake; we shall completely destroy Japan's power to make war."

    Truman said if Japan's leaders "do not now accept our terms they may expect a rain of ruin from the air, the like of which has never been seen on this Earth".

    He added: "Behind this air attack will follow sea and land forces in such numbers and power as they have not yet seen and with the fighting skill of which they are already well aware." 

    What happened after Hiroshima?

    After the bomb obliterated Hiroshima, the Japanese did not surrender.

    Three days later, the US launched another mission to bomb Kokura, however, the city was obscured by clouds. The city of Nagasaki was chosen as a target instead. "Fat Man" was dropped over Nagasaki on August 9, 1945, instantly killing at least 40,000 people.

    The British pilot Leonard Cheshire, who was involved in the mission to bomb Nagasaki, later recalled the cloud caused by the atomic blast: "Obscene in its greedy clawing at the earth, swelling as if with its regurgitation of all the life that it had consumed."

    The bombings were as questionable back then as they are today. Six out of seven five-star US generals and admirals at the time felt there was no need to drop the bomb because Japanese surrender was imminent.

    Devastation after the nuclear bombing of Nagasaki.
    The nuclear bombing of Nagasaki during World War II [Getty Images]

    What was the impact of Hiroshima and Nagasaki?

    On August 15, Emperor Hirohito announced Japan's surrender, and on September 2, the surrender was formally signed, bringing the hostilities of World War II to a close. 

    The power of the atomic bomb would usher a change in geopolitics that still reverberates to this day, with several countries currently vying to acquire this technology. 

    The Doomsday Clock 

    In 1947, the scientists involved in the Manhattan Project created the Doomsday Clock, which represents the likelihood of a man-made global catastrophe, with midnight symbolising the destruction of civilisation as we know it.

    Last year, the clock was adjusted to two minutes to midnight, the closest it has been to doomsday.

    In 2019, the Bulletin of the Atomic Scientists maintained the "two minutes to midnight" time, citing continuing climate change, US and Russian nuclear modernisation efforts; information warfare threats and other dangers from "disruptive technologies" such as artificial intelligence, synthetic biology and cyberwarfare.

    Former California Governor Jerry Brown, left, and former US Secretary of Defence William Perry unveil the Doomsday Clock during on January 24, 2019. This year the Doomsday Clock remains unchanged and is set at two minutes to midnight [File: Mark Wilson/Getty Images]

    SOURCE: Al Jazeera News