The Original Ground Zero

The Atomic Age dawned at 5:29 a.m. on July 16, 1945

by Joe Zentner

“Suddenly, there was an enormous flash of light, the brightest light I have ever seen,” said an American soldier who witnessed the cataclysmic event.

The Atomic Age dawned at 5:29 a.m. on July 16, 1945, in the New Mexico’s Northern Chihuahuan Desert.  The first atomic explosion came less than 50 years after the discovery of radioactivity, in 1896; it synthesized, dramatically, many threads of physics, technology and politics.  The manmade thunder that echoed off the Oscura Mountains that day continues to reverberate through the modern world.  The test was code named “Trinity” and the spot where it occurred came to be known as the Trinity Site.

Dawn over Ground Zero

Why New Mexico?

The story of the Trinity Site begins in June 1942 with the formation of the Manhattan Project, which was established for the express purpose of designing and building an atomic bomb.  At the time it was believed to be a race to beat the Germans who, according to intelligence reports, were building their own atomic bomb.  (In fact, hindsight showed they weren’t.)



Under the Manhattan Project, three large facilities were constructed.  At Oak Ridge, Tennessee, huge gas diffusion and electromagnetic processing plants were built to separate uranium 235 from its more common form, uranium 238.  Hanford, Washington, became the home for nuclear reactors that produced a new element called plutonium.  (Both uranium 235 and plutonium are fissionable elements, which means that their atoms’ nuclei can be split, releasing a large amount of heat energy.  They can therefore be used to produce an atomic explosion.)  Los Alamos was established in New Mexico as the place where the bomb would be designed and built, the center of gravity for the Manhattan Project. 

At Los Alamos, many of the greatest scientific minds of the day labored over the theory and actual construction of the device.  J. Robert Oppenheimer, who had studied at Harvard, Cambridge, Gottingen, Leyden, and Zurich, before joining the faculty of the California Institute of Technology in 1929, led the group.

New Mexico, a thinly populated state with harsh deserts, rugged mountain ranges and secluded canyons, was an ideal place to conduct secret wartime work, although “secret” may be an exaggeration.  People who lived in the area knew something was up.  They saw nearby Santa Fe bustling with newcomers, and they got construction jobs on a mesa known simply as “The Hill,” building acres of apartments and laboratories.  But no matter how much, or how little, residents of New Mexico knew or guessed about the super-secret weapons project, they were forbidden to talk about it under strict wartime rules.

When the Manhattan Project came to the mesa, the Army condemned some 54,000 acres and relocated everyone who lived there, including Pueblo Indians, a few ranchers, and the occupants of a private boarding school for boys.  At first the Army planned for only about 30 scientists and support personnel, but by 1945 the population had swollen to 7,000, including the families of scientists, engineers, and construction workers as well as military personnel.  Since the project was secret, those who were recruited to live at Los Alamos were given only the vaguest idea where they were moving and why.  Their address was a cryptic Post Office Box 1663, Santa Fe, New Mexico.

The streets of the new town were unpaved, the water supply was unreliable, the buildings were firetraps, and there was constant fear of epidemics.  The stress level was tremendous because of the secrecy and high stakes of the lab’s mission, played out against the tragedies of World War II and the miseries of living on the forbidding mesa.

The Trinity Site itself was selected as the location for the world’s first atomic fission explosion because it was isolated from population centers and it was reasonably close to Los Alamos.

Atomic Weapons Theory

Los Alamos scientists devised two designs for an atomic bomb—one using uranium 235 and another using plutonium.  The uranium design was comparatively simple and scientists were confident it would work without testing it.  The plutonium bomb was more complex.  Conceptually, it worked by compressing plutonium into a critical mass to sustain a chain reaction.  Theoretically, compression of a plutonium ball could be accomplished by surrounding it with charges of conventional explosives.  They were designed to all explode at the same instant.  The explosive force would be directed inward, thus smashing the plutonium from all sides.

Redstone Missile

In an atomic explosion, a chain reaction picks up speed as atoms split, thereby releasing neutrons plus enormous amounts of energy.  The escaping neutrons strike and split more atoms, thereby releasing still more neutrons and energy.  In a nuclear explosion, this all occurs in a millionth of a second with billions of atoms being split.

Manhattan Project leaders decided they had to prove the plutonium bomb in a test before they could verify its use as a weapon of war.  From a list of eight sites in California, Texas, New Mexico and Colorado, the Trinity Site was chosen as the test location.  The U. S. government already controlled the area because it was part of the Alamogordo Bombing and Gunnery Range, which had been established in 1942.

The Test

The atomic “device,” as the scientists called the bomb in a classic understated description, was assembled a few miles from Trinity Site in the late spring and early summer of 1945 in a ranch house that had been acquired by the government from a family named McDonald.  At 5:10 a.m., the countdown started; at 5:29:45 a.m. Mountain War Time, the device exploded.  The test was monumentally successful. 

To many observers, the brilliance of the light from the explosionseen through dark glasses – upstaged the shock and sound waves that arrived moments later, though some witnesses remember the sound bouncing off the nearby mountains creating an echoing effect.

Physicist Hans Bethe, one of the participating Los Alamos scientists on hand, wrote: “It looked like a giant magnesium flare which kept on for what seemed like a whole minute but was actually one or two seconds.  The white ball grew and, after a few seconds, became clouded with dust whipped up by the explosion and left behind a black trail of dust particles.”


What happened that day in the New Mexico desert in July 1945 helped mightily to hasten the end of the greatest war the world had ever witnessed.  Should this instrument of death have been used against Japan?  The answer to that question will be argued from now on. 

Trinity Site Afterwards 

The 51,500 acre area was declared a national historic landmark in 1975.  It includes a base camp, where scientists and a support group lived; the ranch house, where the bomb’s plutonium core was assembled; and ground zero, where the bomb was placed for the explosion.

If a visitor does not know the significance of the site, the fenced-in circle of New Mexico desert isn’t much to look at.  All there is to see is a stone obelisk and what looks like the top of a shed buried in the ground.

But Trinity Site isn’t about the visual; it’s about the visceral.  The obelisk and shed are there to add insight to the emotional experience of being on the exact spot of one of the most significant events in human history—the birth of the atomic age. 

The pyramid-shaped obelisk marks exact ground zero, 100 feet below where the bomb was detonated atop a steel tower.  The tower was vaporized in the blast, but near the obelisk is a small outcropping of concrete that was part of the footing for one of the tower legs.  The shed-like structure protects a section of the original crater where radiation levels are still monitored.

There was a special opening of the Trinity Site on July 16, 2005, to commemorate the 60th anniversary of the atomic test.  More than 3,500 people visited the site on that day.

What To See And Do

The Trinity Site is located on the northern edge of the White Sands Missile Range.  Now only slightly radioactive, the site is open to the public twice a year: on the first Saturday of April and the first Saturday of October.  About 3,000 visitors pour into White Sands on each of those days to view the relics of the dawn of the atomic age.  No reservations are necessary, but for security reasons adults entering the missile range property must have a valid photo ID.

After parking, you weave your way through an area of vendor and informational booths.  You then arrive on the edge of a fenced area.  A barbed-wire fence surrounds Trinity Site.  Visitors enter through a large gate and follow a fenced roadway to Ground Zero.

Although the explosion vaporized most of the tower, visitors can still see the stumps of the tower legs in the ground.

At the National Atomic Museum in Albuquerque, visitors can view models of nuclear submarines, examine missile parachutes, look at casings of the atomic bombs used during World War II, and see photos of the scientists who worked together on the Manhattan Project, including J. Robert Oppenheimer, Enrico Fermi, Hans Bethe, Edward Teller and Leo Szilard.  The men all used aliases during the war to prevent their whereabouts from becoming known.  Fermi, for example, was Mr. Farmer.

For additional information, contact:

National Atomic Museum
1905 Mountain Road NW
Albuquerque, New Mexico 87104
Phone 1-505-245-2137

You may well ask, as I have, where was Einstein in all this?  The German-born mathematical physicist, who became world famous for his special and general theories of relativity, in 1942 stated in 1942 that he would decline to participate in the creation of a weapon of mass destruction whose consequences cannot be predicted.  After World War II, Einstein urged international control of atomic weapons.

Brigadier General Thomas Farrell, Deputy Director of the Manhattan Project said of the Trinity explosion, “The effects could well be called unprecedented, magnificent, stupendous and terrifying.  No manmade phenomenon of such tremendous power had ever occurred before.  The lighting effects beggared description.  The whole country was lighted by a searing light with an intensity many times that of the midday sun.” 

Did the scientists who created The Bomb in the New Mexico desert do the right thing?  In thinking about the answer to that question, it is worth remembering that the Dear Departed Leader of North Korea, who had the bomb, reportedly consumed two fifths of consciousness-altering cognac a day.  He prefered the Hennessy label.  (I myself prefer Grand Marnier, but I don’t have my finger on an atomic trigger.) The current leader of North Korea, Kim Jong Un, is reported to favor Johnnie Walker whiskey; and North Korea still has the bomb.

If You Go

If you choose to go to the Trinity Site on one of the two days it is open to the public each year, you will find it 110 miles south of Albuquerque between the Oscura Mountains on the east and the San Mateo Mountains on the west.  It is 60 miles northwest of Alamogordo.

The easiest way to get to the site is to enter White Sands Missile Range through its Stallion Range Center gate, which is five miles south of U. S. Highway 380.  The turnoff is 12 miles east of San Antonio, New Mexico, and 53 miles west of Carrizozo, New Mexico.  The Stallion gate is open for entry during each open house from 8:00 a.m. to 2:00 p.m.  Visitors arriving at the gate between those hours can drive the 17 miles to the Trinity Site without escort.

Another way to visit the site is to drive with a caravan from Alamogordo.  The caravan forms at the Otero County Fairgrounds and leaves at 8:00 a.m.  It is an 85-mile drive to the site from Alamogordo.  The caravan returns between 12:30 and 1:00 p.m. 

During your drive across the Trinity Site, watch for herds of antelope, which roam freely on the range.  The animals are notorious for running in front of oncoming vehicles.  Cameras are allowed at Trinity Site but their use is prohibited anywhere else on the White Sands Missile Range.


Area 51
White Sands National Monument



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