HIROSHIMA | 70 Years On

The mushroom cloud over Hiroshima.

Today in 1945, 70 years ago, the United States dropped an atomic bomb on the Japanese city of Hiroshima.

The war in Europe had ended earlier on May 8 with the surrender of Nazi Germany.

On July 26 the United States, United Kingdom and China issued the Potsdam Declaration, calling on Japan to surrender, warning of "utter destruction" if it did not. Japan refused.

In August, the Manhattan Project detonated an atomic device in the New Mexico desert.

Today at 8:16 local time, a B-29 bomber Enola Gay, called "Little Boy", released a uranium gun-type atomic bomb with the explosive power of 12,000-15,000 tons of TNT. Hiroshima had a military base but the majority of those killed were civilians.

The impact on Hiroshima is measured as:

• 62,000 buildings destroyed
• five square miles flattened
• 80,000 people killed immediately
• approximately half the eventual deaths occurred on the first day
• 35,000 more people died during the next week, of injuries or radiation
• 60,000 more died during the next year from the effects including malnutrition
• 90 percent of the city's doctors were killed by the bomb

Hiroshima after the bomb.

Japan did not surrender immediately after Hiroshima. Three days later, a second bomb, a plutonium implosion-type bomb nicknamed "Fat Man", was dropped on Nagasaki.

Six days later, on August 15, Japan surrendered and on September 2 it signed the document, ending World War II.

A year later, The New Yorker devoted an entire issue to an article by John Hersey, "Hiroshima", which is available online. It opens as follows:

At exactly fifteen minutes past eight in the morning, on August 6th, 1945, Japanese time, at the moment when the atomic bomb flashed above Hiroshima, Miss Toshiko Sasaki, a clerk in the personnel department at the East Asia Tin Works, had just sat down at her place in the plant office and was turning her head to speak to the girl at the next desk.

Terrible things happen in war. Hiroshima and Nagasaki are two of the most terrible wartime events in history. The necessity of one or both bombings is still the subject of argument. The huge ethical issues related to the bombings continue to be debated and the challenge of controlling nuclear weapons is still with us.

Alice and I went with our children to Japan in 1981 and 1986 and we visited the Memorials in Hiroshima and Nagasaki.