The Soviet submarine officer who persuaded his commanding officer to seek clarification from the Kremlin before he dispatched his nuclear warhead into Kennedy's America?

Or the Russian duty officer in a nuclear bunker outside Moscow who witnessed five US missiles about to inaugurate World War III - and didn't tell his superiors, gambling it was a computer error?

It's amazing what you can learn from the Doomsday Clock, which celebrates its 70th anniversary this year.

The Doomsday Clock first appeared on the cover of the Chicago-based Bulletin of the Atomic Scientists in 1947 - two years after US president Harry Truman ordered the deployment of what remain the only two nuclear bombs ever used in warfare, resulting in the destruction of Hiroshima and Nagasaki in Japan and the end of World War II.

But the clock hands have rarely been closer to midnight than now. Earlier this year, the Science and Security Board of the Bulletin decided "to move the minute hand of the Doomsday Clock 30 seconds closer to catastrophe". Suddenly Earth was at 2?? minutes to midnight - the closest our planet has been to annihilation since 1952.

And that was the good news.

The atomic scientists apologised for not turning the clock a full minute closer to Armageddon, explaining it was giving US President Donald Trump the benefit of the doubt: "As this statement is issued, [he] has been the US President only a matter of days."

Still, the scientists hardly pulled their punches about Trump: "The president's intemperate statements, lack of openness to expert advice, and questionable cabinet nominations have already made a bad international security situation worse."

Other culprits were named. Kim Jong-un (for launching two missiles a month during 2016 and boasting in his 2017 New Year message that he'd soon be testing an intercontinental missile). Well, that's one politician who keeps his promises. Vladimir Putin (for ordering the construction of new missiles,). Plus the leaders of China, India and Pakistan ("China is helping Pakistan build submarine platforms. And Pakistan and India continue to expand ... their nuclear arsenals").

But surely the world has been this close to the abyss before?

1948: SEVEN MINUTES TO MIDNIGHT

Soviet dictator Joseph Stalin at his desk in the Kremlin, Moscow. Photo: AP

Three years after the end of World War II, Soviet dictator Joseph Stalin ordered a blockade of the three sectors of Berlin administered by the "Western powers" (the US, France and Britain) which lay within Soviet-occupied East Germany. All railways, roads and waterways to West Germany were cut off from June 24, 1948 to May 12, 1949. It was the first clash of the Cold War.

1949: THREE MINUTES TO MIDNIGHT

US President Harry Truman, centre, with Joseph Stalin, left, and Winston Churchill, right, in 1945. Photo: AP/US Navy

On September 3, 1949, an American U-2 spy plane, flying off the coast of Siberia, picked up the first evidence that the USSR had detonated an atomic bomb in Kazakhstan. President Truman confirmed that to the American people later that month. It was the start of the arms race.

1952: TWO MINUTES TO MIDNIGHT

The cloud from the explosion of a hydrogen bomb by the US in the Marshall Islands in 1952. Photo: AP

On November 1, 1952, the US successfully detonated "Mike", the world's first hydrogen bomb. The 10.4-megaton thermonuclear device destroyed Elugelab Atoll in the Marshall Islands, leaving a crater more than a kilometre wide.

1962: THREE MINUTES TO MIDNIGHT

US President John F. Kennedy addresses the US about the blockade of Cuba. Photo: AP

On October 22, 1962, US president John Kennedy made a TV broadcast ordering a naval blockade of Cuba which - under Communist leader Fidel Castro - had agreed to host Soviet nuclear missiles pointed at the US. What followed were perhaps the most tense 13 days in world history. Kennedy had already tried to topple Castro's regime in 1961 with the failed CIA-inspired Bay of Pigs invasion. Somehow both Kennedy and Soviet leader Nikita Khrushchev kept their nerve and negotiated a truce (Khrushchev agreed to remove the Soviet missiles in return for Kennedy agreeing not to invade Cuba and to remove US missiles directed at the USSR from Turkey).

1962: THREE MINUTES TO MIDNIGHT

An American U-2 spy plane crossed into Soviet airspace in 1962.

Two flashpoints occurred on October 27. In the middle of the Cuban Missile Crisis, pilot Charles Maultsby took off in a U-2 spy plane on a routine flight over the North Pole. Somehow, with his vision obscured by the Aurora Borealis, Maultsby crossed into Soviet air space. Fearing nuclear attack, the Soviets launched several MiG fighter jets. However Maultsby and his U-2 were guided back to Alaska by two F-102 fighters.

On that same day, the destroyer USS Beale began dropping non-lethal depth charges along Kennedy's blockade line around Cuba, to force any enemy submarines to the surface. Several of them detonated close to the nuclear-armed Soviet submarine B-59. Imagining the worst, the submarine commander ordered the launch of B-59's single nuclear missile. Fortunately, his second in command - Vasili Arkhipov - soothed his superior, convincing his fellow officers to seek fresh orders from Moscow. B-59 eventually returned safely to Russia without incident.

1973: 12 MINUTES TO MIDNIGHT

US President Richard Nixon was engulfed by the Watergate scandal at the time. Photo: New York Times

On October 24, 1973, US troops around the world were put on nuclear alert during the Yom Kippur War (when Syria and Egypt invaded Israel). Defcon (Defence Readiness Condition) 3 is the highest state of US armed readiness short of a declaration of war. According to reports, Nixon - then engulfed by the Watergate scandal - slept through the crisis. Henry Kissinger, Nixon's secretary of state, received a message from Leonid Brezhnev advising that the USSR planned an intervention. Kissinger tried to speak to the president, but was told he'd already retired for the night at 9.50pm and couldn't be disturbed. The National Security Council met - without Nixon or a vice-president (Spiro Agnew had resigned in disgrace, but Gerald Ford had yet to be appointed) - and issued a message to Brezhnev in Nixon's name. It worked.

1979: SEVEN MINUTES TO MIDNIGHT

Inside NORAD headquarters in 1979. Photo: AP

On November 9, technicians at Colorado's North American Aerospace Defense Command (NORAD) were convinced the USSR had launched an unprovoked nuclear attack on the American mainland. Ten fighter aircraft were ordered to intercept incoming missiles. The phantom attack was a false alarm: a technician had accidentally run a training program simulating a Soviet attack on the US.

1983: FOUR MINUTES TO MIDNIGHT

An American intercontinental ballistic missile being tested in the US in 1969. Photo: US Air Force

On September 26, Lieutenant-Colonel Stanislav Petrov was the duty officer at Serpukhov-15, an early warning bunker near Moscow where the Soviets monitored their satellite-based detection systems. Tensions were high. On September 1, the Soviets had shot down a Korean Air passenger jet - with the loss of 269 lives - mistaking it for a US fighter plane. So imagine the pressure on Petrov when he discovered the US had fired five intercontinental ballistic missiles at his homeland. Petrov's job was to report any incoming missiles to his military bosses, who would almost certainly have launched a retaliatory strike. His instructions were clear, his training exemplary. But he did not report the US missiles to his superiors. Why would the US - with all its nuclear arsenal - attack with just five missiles, giving the Soviet Union time to respond? Petrov recorded the attack as a computer malfunction - which it was.

1983: FOUR MINUTES TO MIDNIGHT

War games were common during the Cold War. Here US soldiers are en route to NATO exercises in 1983. Photo: AP

In November, NATO launched a routine war game simulating how the US might respond to a conventional attack from the USSR. Such war games weren't uncommon during the Cold War. But Able Archer 83 was unprecedented in its scope: 19,000 US troops were airlifted to Europe and the alert status raised to Defcon 1. Unfortunately, Able Archer 83 also perfectly matched how the Soviets anticipated a nuclear attack on their country might start. Fighter jets in East Germany and Poland were poised for a counterstrike until November 11 - when Able Archer ended peacefully.

1989: 10 MINUTES TO MIDNIGHT

East German border guards on the Eastern side of the Berlin Wall as it comes down in November, 1989. Photo: AP

Mikhail Gorbachev, leader of the Soviet Union, decided not to intervene as East Germany, Poland, Czechoslovakia, Hungary and Romania all rebelled. The signature moment came on November 9, 1989, when West and East Germans united in demolishing the Berlin Wall.

1991: 17 MINUTES TO MIDNIGHT

US President George Bush and Soviet leader Mikhail Gobachev in 1990. Photo: US Information Service

This was the safest year since the Doomsday Clock was created. The Cold War was officially over and the US and Russia began making significant reductions to their nuclear arsenals through the Strategic Arms Reduction Treaty.

1998: NINE MINUTES TO MIDNIGHT

A still taken from footage showing Pakistan's missile testing in1998. Photo: AP

India and Pakistan hold nuclear weapons tests three weeks apart.

2002: SEVEN MINUTES TO MIDNIGHT

The attack on the World Trade Centre in New York on September 11, 2001. Photo: AP

Following al-Qaeda's attack on the Twin Towers and the Pentagon on September 11, 2001, greater focus was placed on the threat of terrorist organisations getting hold of nuclear weapons. The Bulletin pointed out "the enormous amount of unsecured - and sometimes unaccounted for - weapon-grade materials" located throughout the world. Meanwhile US president George W. Bush's government rejected a series of arms control treaties and announced it would withdraw from the Anti-Ballistic Missile Treaty.

2007: FIVE MINUTES TO MIDNIGHT

Iran's Natanz uranium enrichment facility as seen in 2007. Photo: AP/GeoEye/SIME

As North Korea (under Kim Jong-il) conducted a nuclear test, fears grew that Iran was also seeking to become a nuclear power. For the first time, the Doomsday Clock also took account of man-made climate change.

2015: THREE MINUTES TO MIDNIGHT

Unchecked climate change was a factor for the scientists behind the clock. Photo: Nick Moir

Setting the Doomsday Clock at its most dangerous level since the Reagan administration, the Science and Security Board noted: "Unchecked climate change, global nuclear weapons modernisations, and outsized nuclear weapons arsenals pose extraordinary and undeniable threats to the continued existence of humanity ... These failures of political leadership endanger every person on Earth."

2017: TWO-AND-A-HALF MINUTES TO MIDNIGHT

North Korean leader Kim Jong-un. Photo: AP

Noting Kim Jong-un's bellicose march towards intercontinental nuclear weapons, and the potential for "lethal automomous weapons systems that make 'kill' decisions without human supervision", the Science and Security Board concluded: "The Clock is ticking, global danger looms. Wise public officials should act immediately, guiding humanity away from the brink. If they do not, wise citizens must step forward and lead the way."