By Dennis Overbye

TRINITY SITE, NM — Once, in another lifetime, I witnessed an atomic explosion. This was in the 1960s at the Nevada Test Site, a vast area about an hour northwest of Las Vegas where the US military tested bombs. I was working for EG&G, a military contracting company that, among other atomic chores, supplied all the instrumentation for the test site; it is now part of a company called Amentum. My job, to study the effects of nuclear explosions on the atmosphere, was sufficient to keep me out of the Vietnam War draft.

Cabriolet, as the test was called, contained the force of 2,300 tonnes of TNT. Detonated hundreds of feet underground, it was louder than I thought anything could ever be. The ground bulged, and a line of torches marking ground zero flew into the air. From a shaking trailer 4 miles away, my boss and I filmed tongues of fire erupting from the earth and congealing into an elephant-shaped cloud of dust that drifted off in the general direction of Montana.

Those were heady days in the atomic business, when people thought they could build harbours in a few microseconds of fury, or dig a new Panama Canal overnight in a domino of blasts, or even propel spaceships. Cabriolet was part of the Plowshare Program, which looked for peaceful civilian uses of nuclear explosions. Turns out all they are good for is terror.

Where it all began

Twice a year, on the first Saturdays of April and October, the US Army opens the gate to the White Sands Missile Range in New Mexico, allowing in civilians to tour a patch of sand known as the Trinity Site, where the very first atomic explosion was set off and the history of nuclear dread began. It was so named by J. Robert Oppenheimer, the physicist who led the Manhattan Project to build the bomb, inspired by lines like these in the poems of John Donne.

Batter my heart, three-person’d God, for you

As yet but knock, breathe, shine, and seek to mend;

That I may rise and stand, o’erthrow me, and bend Your force to break, blow, burn, and make me new.

According to the Trinity website, the Stallion Gate would open promptly at 8:00 a.m.; when we arrived not long after the crack of dawn, a 4-mile-long caravan of cars was ahead of us. The idea to visit came from Michael Turner, an old friend and cosmologist who recently retired from the University of Chicago and now with the Kavli Foundation in Los Angeles.

Turner had grown up under the Promethean promise of that mushroom cloud and 20th-century science. Everybody who was anybody in physics had worked on the Manhattan Project. As a young physicist in the 1960s and ’70s, Turner was part of a young band of physicists who invaded astronomy and turned cosmology into particle physics or perhaps vice versa. He had never visited the Trinity Site — he hadn’t known you could go there until recently, he said. And being open only two days a year presented a logistical challenge.

He brought along an old pal from his undergraduate days at the California Institute of Technology, Robert J. Miller, who had helped invent the computer touchpad.

Once inside the gate, we drove for a half-hour, past desert hills dotted with radar and telescope domes, to a dusty parking lot manned by fresh-faced young men in Army camo fatigues. A line of port-a-potties occupied one corner of the lot, arrayed as if for an outdoor rock concert.

The first thing on display was the Jumbo, a steel barrel 12 feet or so wide with walls as much as 16 inches thick; it rested on its side like a culvert, allowing visitors to walk through. The original plan was to detonate the Gadget — the Manhattan Project physicists’ term for the bomb — inside the Jumbo. If the bomb fizzled, the Jumbo would corral the $250 million worth of plutonium that was the explosive core of the device.

We continued through a gate and down a path lined with barbed wire, Keep Out signs and warnings about rattlesnakes, to a fenced-in area littered with glassy gravel, sand, and tufts of sagebrush and sparse grass. It was here at 5:29:45 a.m. on July 16, 1945, that arguably the most consequential physics experiment of the 20th century took place.

The bomb would use explosives to squeeze a softball-size lump of plutonium to critical density, ideally resulting in a soul-rattling explosion. It worked, lighting up the New Mexico landscape a few minutes before dawn and causing Oppenheimer to mutter to himself a verse from the Bhagavad Gita: “Now I am become death, destroyer of worlds.”

Three weeks later, on Aug. 6, 1945, a bomb of slightly different design was dropped on Hiroshima, killing an estimated 140,000 people. It shot two hunks of uranium together, creating the critical mass needed for a chain reaction to occur; scientists were so certain the design would work that they did not even bother testing it before it was deployed. Fat Man, a plutonium bomb of the kind tested at Trinity, was used on Nagasaki on Aug. 9, and the end of World War II soon followed.

Trinkets of the Apocalypse

At Trinity’s ground zero, hundreds of people were milling around as if at a county fair, but there was little to see. The detonation created a crater 8 feet deep, a half-mile wide and lined with glassy pebbles called trinitite: sand that had been swept up in the fireball, vaporized and then fell back down in molten radioactive droplets. But gradually the pebbles were shovelled out and the hole filled with scrubby sand, weeds and rocks. Now display stands sold snacks and souvenirs; at one table, docents were using a Geiger counter to show off mildly radioactive rocks.

The Gadget was detonated atop a 100-foot tower. All that remained was an inch-long stub of metal sticking out of the ground. An obelisk of black rocks, with a plaque commemorating the event, marked the exact point of ground zero; we took turns posing in front of it and a life-size model of Fat Man, which resembled a short, bulbous submarine with enormous tail fins.

The ground below our feet was littered with green shards of trinitite. They were allegedly radioactive, and signs warned that removing any stones constituted theft of government property and could lead to fines or even jail time.

The signs seemed to remind visitors to bend down and retie their shoelaces, perhaps to gather a promising souvenir or two of the original sin in the process. Some days later, in an email, Turner wrote that his piece of trinitite “has a proud place in my rare gem collection, kept two meters away from me (for radioactive safety. :-).”

Any such caution was unnecessary for me. On returning home, I took my bounty of trinitite to the office and gave it to a colleague whose spouse taught chemistry and had access to a Geiger counter. I was hoping that my pebbles would be at least as radioactive as a banana, but my friend’s verdict came the next day. “Pathetic,” he said.

A brief history of Atomic Warfare

There are now more than 13,000 nuclear warheads on Earth, according to a recent compilation by the Federation of American Scientists. Perhaps miraculously, not one has been detonated in anger since 1945, although stories keep emerging of close calls.

Recently it was revealed that when the Chinese Communists seemed to be threatening Taiwan in 1958, the US military drew up plans to bomb mainland China. Another near tragedy occurred on Sept. 26, 1983, three weeks after Soviet fighters had shot down Korean Air Lines Flight 007.

Stanislav Petrov, a lieutenant colonel in the Soviet air defence forces, was in charge that day of a command centre called Oko (‘eye’, in Russian), an early-warning system that relied on a network of satellites to detect attacks. The system reported that a half-dozen missiles had been launched from the United States and were headed toward the Soviet Union.

Petrov’s task was to relay the warning to his superiors in Moscow, who were likely to order a retaliatory strike. But Petrov, an engineer by training, held back, worried that the signal might be a false alarm. Several tense minutes in the early-warning command centre passed by until finally, ground-based radar confirmed that no missiles were incoming. The error was later traced to unusual reflections from high-altitude clouds.

Petrov was later reprimanded for insufficiently documenting his work on that day. To the rest of the world, he was a hero. In 2006 he was invited to address the United Nations and tour the United States, a trip that was documented in a film, ‘The Man Who Saved the World’.

In the course of his United Nations visit, he visited a Minuteman missile silo and its deactivated missile.

“Wow,” the former Soviet colonel says in the film. “You’re beautiful.”

Then his guide, a friendly young man, begins to explain that, according to policy, the weapon would have been launched only in response to a Soviet attack. Petrov erupts. “Brainless goat,” he says. “We were doing the same thing. We weren’t creating weapons to attack you, we were creating them for defence.”

Asked if atomic bombs would ever be used in war again, Petrov pauses. “I think so,” he says. “It’s absurd.”

-New York Times