Trinity Site: Inaugurating the Atomic Age

The Trinity test site of the Fat Man plutonium bomb is tucked well inside the 2.2 million desert acres of the White Sands Missile Range in southern New Mexico. We walked the dusty site—still speckled with Trinitite, sand fused by the detonation into green glass—during the last day of the MIT Alumni Travel Program tour, Entering the Atomic Age: The Manhattan Project. We had prepared for that moment with lectures on science and technology and stories by participants who made the history come alive. Now it was time to walk the very first place on Earth where a nuclear weapon was detonated. We were a pretty silent and thoughtful bunch, as the wind swept over the desert plain.

The Hiroshima bomb, Little Boy, was fueled with uranium-235, which was extremely difficult to extract but was sure to work with a gun-type mechanism. That bomb was assembled in flight because they didn't want an armed nuclear bomb going up in a B-29, which was prone to burst into flames on take off. But once up in the air, they were confident it would work—and it did. U-235  was so difficult to extract, however, there would be only one bomb for quite a while. So the Los Alamos team came up with a different solution, a bomb using plutonium-239, which was easier to derive but detonating it was tricky. The solution required a circle of high explosive charges that fired inward simultaneously to cause an implosion. The plutonium bomb was successfully tested July 16, 1945, and President Truman shared the results with Allied leaders at the Potsdam Conference. The world learned of atomic bombs when Little Boy was used Aug. 6.

Great stories, terrific conversations. The five-day trip was filled with personal stories from  people who had worked and lived in Los Alamos during the tumultuous heart of the Manhattan Project in 1943–45. Guide Ellen Bradbury, who grew up in Los Alamos, described visiting the weaponeer who helped launch Fat Man. The flight from Tinian Island to Japan bypassed the first target city and flew on to Nagasaki because of cloud cover. The crew nearly had to ditch the plane because they were short of gas—radio silence prevented coordination with accompanying planes, which were obscured by clouds, so the pilot circled for an hour at a rendezvous point. One traveler, a retired Boeing executive, described the company's first test flight of the B-29, which ended in a crash and loss of all on board. The engine was redesigned but remained an unpredictable element in bomb delivery. A scholar described the women involved in the science and development project including Lise Meitner, a co-discoverer of fission who was overlooked when the Nobel Prize went to her male partner.

Great conversations continued the learning. Topics ranged from nuclear technologies to the personal challenges of leaders like Robert Oppenheimer to lingering questions on how the nuclear bombs were first used. Many travelers had studied the era for years, but each of us gained new insights from walking the sites and hearing the voices of those who lived the Manhattan Project.

Nancy DuVergne Smith

Learn about MIT’s connections to the Manhattan Project in the first trip post and the group’s visit to Los Alamos National Laboratory.

Read about new work in  MIT’s Nuclear Science and Engineering department including the 2009 update on the Future of Nuclear Power.

PS: Learn about other MIT Alumni Travel Program trips.