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The Third Bomb

“War Reserve Unit IV” sits in perpetual retirement at the National Museum of Nuclear Science & History in Albuquerque, NM

Story and Photos By Bill Newcott
August 6, 2020

“Let me show you the gadget,” says James Walther. My eyes take a moment to adjust as we step from the glaring, hot air of an Albuquerque, New Mexico summer into the dark, cool expanse of the National Museum of Nuclear Science and History — its usually busy galleries eerily empty in this year COVID-19.

The museum’s director leads me past an array of unlit displays — the stretch sedan America’s first atomic scientists rode across the New Mexico desert…a hunk of uranium from Hitler’s nuclear program…equipment used to build the first nuclear bomb — until we stop in front of an enormous spherical device. The thing bristles with dozens of cables, each linked to what appears to be a kind of spark plug. It’s shiny, complex, strangely beautiful — and with a little bit of bad luck it could have incinerated and irradiated hundreds of thousands of Japanese in 1945.

This is the Third Bomb.

After a jaw-dropping detonation in New Mexico — known to history as the Trinity Test — the world’s first atomic weapon was dropped by the United States on Hiroshima on August 6, 1945. When the Japanese failed to immediately surrender, on August 9 a second atomic device was detonated over Nagasaki. Still, there was no definitive word that the Empire was about to give up as some persistent Japanese government war hawks were willing to gamble the U.S. didn’t have any more of these devastating weapons. We can still wait out the Allies, they said. But they were wrong.

About 80 miles north of where James Walther and I are standing now, in the small town of Los Alamos, scientists and engineers of the Manhattan Project were assembling a third bomb, identical to the one dropped on Hiroshima. Known as “Fat Man” because of its wide girth, also referred to as “The Gadget” by its creators, the bomb was both astonishingly advanced and devilishly simple: It consisted of a small core of uranium surrounded by 5,000 pounds of high explosives. When those explosives were detonated at the same millisecond, they compressed that uranium core until it reached critical mass — at which point it exploded with the power of 12 kilotons of TNT.

Outside the museum, a Fat Man replica hangs from a copy of the Trinity Site shot tower.

The first Fat Man had leveled a square mile of Hiroshima. This one would be just as devastating. Fat Man II’s aluminum shell had already been cast by the time the Nagasaki bomb was dropped. All that was needed was a new uranium core, and that was being processed. In fact, General Leslie Groves, head of the Manhattan Project, reported to President Harry S Truman, production of Fat Man II was well ahead of schedule.

  “We have gained 4 days in manufacture and expect to ship from New Mexico on 12 or 13 August the final components,” Groves wrote. “Providing there are no unforeseen difficulties in manufacture, in transportation to the theatre or after arrival in the theatre, the bomb should be ready for delivery on the first suitable weather after 17 or 18 August.”

Japan’s leaders never knew how close they were to a third atomic attack. On the 17th, Emperor Hirohito spoke to the nation — the first occasion any of his subjects had heard his voice — announcing surrender in the face of “a new and terrible weapon with the power to destroy many innocent lives and do incalculable damage.”

And so Fat Man II went into obscure retirement, and now it’s sitting harmless on the floor of a New Mexico museum.

“This is War Reserve Unit Four,” says Walther. “There’s obviously no plutonium in it, but this is the original aluminum casing. This would have been the next bomb had the Japanese not surrendered.”

Each of those wires leads to the point where the bomb would have had an explosive charge aiming inward toward the plutonium.

Original Manhattan Project equipment at the museum.

“And each one had to be exactly the same length,” Walther says. “There were no electronics then — just batteries and phone switches.”

It’s humbling to stand in the presence of the weapon that changed history forever — but even more astonishing to realize that in 75 years, no other device has pushed its way ahead of Fat Man II to become the third nuclear bomb detonated in combat. For all the saber rattling of the Cold War, for all the bitter border wars among Asian nuclear powers, for all the tensions that bedevil the Middle East, Fat Man II sits in his glass case at the end of a museum corridor, the first of tens of thousands of nuclear weapons to have not been unleashed. 

Some destinies are best left unrealized. 

The National Museum of Nuclear Science & History is at 601 Eubank SE (at Southern Blvd), Albuquerque, New Mexico
(505) 245-2137

For more of Bill Newcott’s coverage of the dawn of the nuclear age, see his National Geographic article: I Trekked To a Nuclear Crater To See Where The Nuclear Age Began.



Published by Bill Newcott

Award-Winning Film Critic, Columnist, TV Host and Creator of AARP's Movies For Grownups, Bill writes for publications including National Geographic, The Saturday Evening Post, Delaware Beach Life, Alaska Beyond and Northwest Travel.

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