New Mexico site of the first successful test of an atomic device. By 1945 the manhattan Project had produced sufficient plutonium for several fission bombs, but scientists were unsure of the reliability of the implosion technique required to initiate a chain reaction and an explosion. Small-scale experiments were unrevealing, since nothing below critical mass can explode. Thus, Major General Leslie R. Groves, overall director of the manhattan Project, authorized a full-scale test (known as Trinity) of the implosion technique. The Jornada del Muerto (Dead Man's Trail) near Alamogordo, New Mexico, was chosen as ground zero for the explosion. Isolated and ringed by peaks, the site helped to preserve secrecy and contain radioactive fallout, the effects of which were not yet then fully known.

Secured on top of a 100-ft steel tower, the device exploded at 5:30 a.m. on 16 July 1945. With a predicted minimal yield of 500 tons of trinitrotoluene (TNT) and an optimal yield of 5,000 tons if all parts functioned synergistically, the device actually produced a yield of 20,000 tons of TNT. Accompanied by a powerful shock wave and an awesome roar, the device vaporized the tower, creating a crater 400 yards in diameter. A mushroom cloud rose to 41,000 ft; the explosion was heard from 100 miles away, and the light produced was seen from 200 miles. To allay concerns of local residents, army officials reported that an ammunition dump had blown up.

Scientists were awestruck by the power of the explosion. Julius Robert Oppenheimer famously recalled the god Vishnu's line from the Bhagavad Gita: "I have become death, shatterer of worlds." Groves predicted, "The war's over." A report was quickly passed to President Harry S Truman at Potsdam, whose negotiating stance with Josef Stalin hardened considerably based on the stunning results of the Trinity test.

The Trinity test site is located on White Sands Missile Range. It is open to the public twice a year: the first Saturday in April and the first Saturday in October.

William J. Astore

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Further Reading
Lamont, Lansing. Day of Trinity. New York: Atheneum, 1965, 1985.; Storms, Barbara. Reach to the Unknown: Part 1: Trinity. Special Twentieth Anniversary Edition of the Atom, July 16, 1965. Los Alamos, NM: Office of Public Relations, 1965.; Szasz, Ferenc Morton. The Day the Sun Rose Twice: The Story of the Trinity Site Nuclear Explosion, July 16, 1945. Albuquerque: University of New Mexico Press, 1984.