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Death Notice

Iwao Ogawa

1922 - 13 June 2006
Tokyo, Japan
Rikkyo University

Submitted by Physics Today Editorial Staff

Published on 16 June 2006

Current comments and reminiscences on Iwao Ogawa:

This is sad news.

Iwao Ogawa, Professor Emeritus of Rikkyo University, Tokyo,
who was the last survivor among the participants at the First
Pugwash Conference in 1957, passed away in Tokyo, Japan,
on June 13, 2006 at the age of 84; by lung cancer.

He attended eight Pugwash Conferences in 1957, 1958, 1962,
1967, 1977, 1981, 1987, 1995 and three Symposiums in 1975,
1989, 1997, including the Symposium held at Pugwash, Nova Scotia, Canada to commemorate the 40th Anniversary of the First Conference.

He gave various contributions to radiation physics and nuclear physics. He watched the Hiroshima Bomb explosion from a distance in 1945. He measured and analysed radioactive fallout from surface and atmospheric nuclear weapon tests in the 1950's.

The funeral will be held at Myofukuji Temple, Tokyo at 10:30 am
(in Japanese standard time, which is ahead by 9 hours from
the universal Greenwich time) on June 16, 2006.

He is survived by his wife Ikuko and two sons.

Iwao Ogawa was the only Japanese nuclear physicist known to have observed the 1945 explosion of the atomic bomb over Hiroshima. At the time, he was teaching at the Imperial Japanese Naval Academy, 10 miles south of the city. Almost immediately he organized research groups to study the explosion, and came to the conclusion that it was an atomic weapon, something he knew that two groups in Japan had been working on.

In an New York Times article published in 1982, he said ''Our first clue was that X-ray film in the hospitals had all been blackened, exposed.... 'That could only have happened by radiation. We also had seismologists who measured the distance from Hiroshima at which gravestones had been toppled. Their estimate of the bomb's size proved very accurate."

''The bomb was a terrible thing.... 'But until it was dropped, the navy officers were very confident they could fight on. After it, they came to me and asked for books about physics. It may have shortened the war.''

Ogawa, was one of three Japanese delegates to the first meeting between American and Soviet Scientists during the Cold War. The meeting, in Pugwash Nova Scotia, led to the formation of Pugwash Conferences on Science & World Affairs, and led the groundwork to the 1963 Atomspheric Nuclear Test Ban Treaty and to the biological and chemcial weapons conventions.