ENOLA GAY, the American B-29 bomber, dropped an atomic bomb on Hiroshima 70 years ago today.
The apocalyptic explosion in the Japanese city wiped out thousands of the 350,000 people who lived there, while the physical effects from radiation are still being felt generations later.
Three days later another nuclear device fell on Nagasaki, hastening Japan’s surrender and the end of World War Two. MARTIN PHILLIPS charts the first devastating seconds of the attack and its dreadful aftermath.
8.15am (Hiroshima time) – Bombardier Colonel Thomas Ferebee pulls the lever to release Little Boy – the first nuclear weapon used in warfare – from Enola Gay, 31,060ft above Hiroshima.
The bomb is the result of the US-led Manhattan Project, a plan to build and drop the first atomic bomb. It is 9ft 10in long, 2ft 3in wide and weighs 9,700lb.
Its target is the Aioi Bridge over the Ota and Motoyasu rivers.
8.15am + 43 seconds – bomb is blown 820ft off target, detonates at 1,970ft over a surgical clinic.
8.15am + 44 seconds – it creates a blinding flash of light and a fireball 1,200ft across, with a core temperature of more than 1,000,000C and a surface temperature of 6,000C (the melting point of iron is 1,500C).
Victims in its immediate path are incinerated, leaving only their shadows on the scorched walls and pavements where they were standing.
A shock wave faster than the speed of sound is released, with atmospheric pressure 1,640ft from the blast reaching 19 tonnes per square metre. Splintered glass and other debris fly from buildings obliterated in its path.
Everyone within 1.1 miles subjected to at least 5lb per square inch of pressure is killed.
Within miliseconds, the sudden expansion of air is reversed in a devastating backdraught capable of sucking eyeballs out of sockets and exploding internal organs of anyone still alive.
8.15am + 47 seconds – heat from the fireball causes birds flying more than a mile away to burst into flames.
A thunderous roar is heard and a mushroom cloud surges into the stratosphere. It carries dust, debris and 98 per cent of radioactive material that didn’t react to cause the initial blast.
8.16am – simultaneous fires start all over the blast-damaged area.
8.35am – the blazes, fuelled by debris, broken gas pipes, existing fires and electrical shorts, merge into a firestorm that consumes everything flammable within two miles of the blast centre.
It accounts for 60 per cent of the 80,000 people killed (including 20,000 soldiers) and 70,000 hideously injured in the blast.
8.45am – black rain falls from the mushroom cloud, showering the city with mud, dust, soot and radiation.
2.58pm – Enola Gay lands at base on the Pacific island of Guam, 12 hours, 13min after it took off.
In Hiroshima, survivors vomit and show other signs of radiation sickness.
August 7 – further radiation sickness sets in, including fever, tiredness, bleeding gums, hair loss and diarrhoea which, for some, will last for months. The worst affected will die within three weeks. Power is restored to some areas.
August 8 – Manhattan Project scientist Dr Harold Jacobsen predicts Hiroshima’s devastated centre will remain dead, “not unlike our conception of the Moon”, for 70 years. A limited rail service resumes in Hiroshima.
August 9 – a second nuclear bomb, codenamed Fat Man, is dropped on Nagasaki, prompting the Japanese surrender and the end of World War Two.
August 27 – those exposed to the highest doses of radiation are dead, but the number suffering radiation sickness keeps rising.
More than half the survivors who were within 1.2 miles of the blast are severely scarred, with increased risk of hepatitis, liver damage, and thyroid and heart disease.
September – red Cannas grow in the Hiroshima rubble, 2,600ft from the centre of the blast-damage zone.
September 17 – Makurazaki typhoon hits, killing more than 2,000 people and flooding large areas. Floodwaters bring radiation-free topsoil and sand.
October – the rate of new radiation fever cases slows. More than 6,000 people who survived the blast and fire will die from radiation injuries.
Spring 1946 – Hiroshima’s cherry trees blossom.
Summer 1946 – Oleander flowers, the official plant of Hiroshima, bloom in the rubble.
1947 – the US sets up the Atomic Bomb Casualty Commission to study the effects of radiation on survivors.
Around one third of those who suffered radiation injuries recover, but with a lifelong increased risk of cancer. Some children develop signs of leukaemia.
1949 – Hiroshima is declared City of Peace by mayor Shinzo Hamai. Designs for the Peace Memorial Park take shape, while Prefectural Industrial Promotion Hall, the ruined building closest to the blast centre, is named The Atomic Dome.
1952 – Japan is independent again after US forces leave.
1955 – Hiroshima’s population returns to pre-war levels. The Peace Memorial Museum opens.
1956 – cancer diagnoses among survivors rise and continue during the Sixties.
1966 – Peace Pagoda is built in the Peace Park.
1998 – Peace Institute and Hiroshima University established.
2015 – Hiroshima is a thriving industrial city.