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Hiroshima and Nagasaki: Humanity’s first encounter with the bomb

On the 80th anniversary of Hiroshima and Nagasaki, Professor Nicholas Wheeler explores how fear of nuclear destruction is not an effective deterrent.

6 August 2025•Long read
Black and white photo of Hiroshima, Japan, after the atomic bomb attack of 8 August 1945 showing the Genbaku Dome

The Genbaku Dome in Hiroshima, Japan, after the atomic bomb attack of 8 August 1945. Credit: Pictorial Press, via Alamy.

Eighty years ago, today the world entered its nuclear epoch. The atomic bomb dropped by the US on the Japanese city of Hiroshima killed between 70,000 and 140,000 civilians by the end of that year. J. Robert Oppenheimer, the physicist who led the scientific effort to build the bomb, later quoted the Bhagavad Gita upon witnessing the explosion: “Now I am become Death, the destroyer of worlds.”

A stark reminder of this immense destructive power came last week, when President Trump announced the redeployment of two US submarines – presumably Ohio Class nuclear-powered ballistic missile submarines (SSBN) – in response to what he called “highly provocative statements” by the former Russian President Dmitry Medvedev. It may have been empty posturing by Trump, but one Ohio SSBN (the US Navy has 14 in its fleet) under the 2010 New START arms control treaty limits carries approximately 90 warheads – each warhead having destructive power many times greater than the bomb dropped on Hiroshima.

For many years, it was believed that building an "atomic weapon"– the term coined in 1914 by H.G. Wells in his book The World Set Free–was simply infeasible given the amount of Uranium 235 required for a bomb. However, this cardinal assumption changed in March 1940 when two refugee physicists – Rudolf Peierls and Otto Frisch, who both worked at the University of Birmingham – produced in March 1940 what became known as the Frisch–Peierls memorandum. Brought together by the university’s chair of physics, Sir Mark Oliphant, their memorandum showed that a powerful atomic bomb could be built using only a small amount of uranium-235.

While factors such as national ambition and status played a role in proliferation, a key driving force was fear – of adversaries achieving a lasting decisive strategic advantage and, in the case of North Korea, protecting the regime from external attack.

Professor Nicholas J. Wheeler, University of Birmingham

What drove Frisch and Peierls was fear that Nazi Germany might build the bomb first. As they wrote in their memorandum: “If one works on the assumption that Germany is, or will be, in the possession of this weapon… The most effective reply would be a counter-threat with a similar bomb. Therefore it seems to us important to start production as soon and as rapidly as possible… it would obviously be too late to start production when such a bomb is known to be in the hands of Germany, and the matter seems, therefore, very urgent.”

Frisch and Peierls had no access to the relevant authorities, and it was Oliphant who submitted the memorandum in secret to the British Government. Prime Minister Winston Churchill heeded the message, establishing a month later the MAUD committee to investigate the military consequences of atomic energy. It reported in secret in July 1941, urging production of the bomb and that Britain should cooperate with the US in this endeavour. In a now-famous line, the Committee said, “No nation would care to risk being caught without a weapon of such decisive possibilities.”

The demonstration of what the atomic bomb was capable of at Hiroshima – and then again three days later with devastating effect at Nagasaki - spurred others to follow the MAUD Committee’s logic. The Soviet Union, fearing a US atomic monopoly, tested its first bomb in 1949. Britain joined the nuclear club in 1952, followed by France in 1960 and China in 1964. It is widely accepted that Israel had developed nuclear capability by the early 1970s – though it has maintained a position of ambiguity. India and Pakistan became declared nuclear powers in 1998, and North Korea followed in 2006.

While factors such as national ambition and status played a role in proliferation, a key driving force was fear – of adversaries achieving a lasting decisive strategic advantage and, in the case of North Korea, protecting the regime from external attack.

However, nuclear fear and the deterrence it makes possible are a fragile basis on which to safeguard humanity’s future.

Professor Nicholas J. Wheeler, University of Birmingham

Yet fear’s centrality to the nuclear story is not only in relation to its role as a driver of proliferation. Nuclear fear has also been a source of restraint – keeping what English novelist Martin Amis once called “Einstein’s Monsters”

at bay. The most dramatic manifestation of this was the October 1962 Cuban Missile Crisis. It was the mutual fear of nuclear catastrophe that drove the then US president, John F. Kennedy, and his Soviet counterpart Nikita Khrushchev to de-escalate the crisis. As I have argued elsewhere, shared fear and vulnerability led Kennedy and Khrushchev to develop empathy and trust – a key factor in the peaceful resolution of the crisis.

However, nuclear fear and the deterrence it makes possible are a fragile basis on which to safeguard humanity’s future. The world may have avoided the use of nuclear weapons since August 1945 through a combination of prudent statecraft and good luck. But how long is it before some combination of bad luck and reckless risk-taking leads to the use of nuclear weapons once again?

Russian nuclear sabre-rattling over Ukraine and the May 2025 conflict between India and Pakistan, unleashing unprecedented levels of conventional military force between two nuclear-armed states, are warnings that the "Sword of Damocles" Kennedy warned about still hangs over humanity.

The Bulletin of the Atomic Scientists, established by Albert Einstein and Oppenheimer in 1945, created the Doomsday Clock two years later to symbolise how close humanity is to nuclear catastrophe. In January 2025, the clock was moved one second closer to midnight, a stark reminder of the growing risks we face – not only from nuclear weapons, but also climate chaos and threats from new disruptive technologies like AI and biotech.

It is now the closest to midnight it has ever been. There is growing fear among governments, civil society and elites that the risks of nuclear war are greater today than at any time since the Cuban Missile Crisis. This includes the early 1980s, when the risks of nuclear war between the superpowers loomed large.

The bomb may have been born in fear, but only the building of trust – which may spring from that fear – can ensure it is never used again.

Professor Nicholas J. Wheeler, University of Birmingham

However, even in that period of deep distrust and nuclear fear, the US and the Soviet Union had some shared guardrails and channels of communication. Arms control agreements that followed the Cuban Missile Crisis limited superpower competition through the 1960s and 1970s and continued to restrain US-Soviet competition into the early 1980s.

Today, arms control has all but collapsed while reliable and trusted channels of communication between major nuclear adversaries are virtually non-existent. The prospects for regulating the nuclear arms competition between Russia, the United States, and China are bleak.

To mark the 80th anniversary of the advent of the nuclear epoch, and to issue yet another warning about the ever-increasing risk of nuclear war, the Nobel Laureate Assembly – a gathering of Nobel Laureates and nuclear experts at the University of Chicago – warned in its 2025 “Declaration for the Prevention of Nuclear War” that, “Ultimately, security cannot be built on fear.”

Seventy years earlier, Einstein and the philosopher Bertrand Russell had issued their famous “Russell-Einstein Manifesto.” Signed by 11 signatories, the Manifesto was created principally as a trust-building project between East and West. The manifesto concluded, “We appeal as human beings to human beings: Remember your humanity, and forget the rest. If you can do so, the way lies open to a new Paradise; if you cannot, there lies before you the risk of universal death.”

We now face the same choice the manifesto laid bare. One path leads to annihilation, the other to survival through a recognition of our common humanity. Japan gives expression to that common humanity every 6 and 9 August, when the cities of Hiroshima and Nagasaki hold their peace memorial ceremonies. Remembering the victims and those who continue to suffer from the effects of the atomic bombings, these peace memorials look to a future where nuclear weapons no longer exist or are part of the imagination of political and military leaders. The bomb may have been born in fear, but only the building of trust – which may spring from that fear – can ensure it is never used again.

This is an expanded version of an article that Professor Wheeler wrote for The Conversation.

Professor Wheeler wishes to give a special thanks to Professor Mark Dennis of the School of Physics and Astronomy at the University of Birmingham for sharing his perspective on the Frisch-Peierls memorandum and for their ongoing conversations on humanity’s encounter with the bomb.

Notes for editors

  • Nicholas Wheeler is Professor of International Relations in the Department of Political Science and International Studies at the University of Birmingham and a Non-Resident Senior Fellow at BASIC (the British-American Security Information Council).

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  • Professor Nicholas J. Wheeler

    Professor of International Relations

    Nicholas J. Wheeler is Professor of International Relations and Director of the Institute for Conflict, Cooperation, and Security at the University of Birmingham.

    Phone: +44 (0)121 414 6215
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