White Sands Proving Grounds in Socorro County, New Mexico — The American Mountains (Southwest)
the world's first
was exploded on
July 16, 1945 Erected 1965
White Sands Missile Range
J. Frederick Thorlin
Major General U.S. Army
(The lower marker reads):
has been designated a
National Historical Landmark
This Site Possesses National Significance
In Commemorating The History of the
United States of America
National Park Service
United States Department of the Interior
Erected 1965 by White Sands Missile Range.
Marker series. This marker is included in the National Historic Landmarks marker series.
Location. 33° 40.638′ N, 106° 28.517′ W. Marker is in White Sands Proving Grounds, New Mexico, in Socorro County. Touch for map. Marker is in this post office area: White Sands Missile Range NM 88002, United States of America. Touch for directions.
Other nearby markers. At least 1 other marker is within 2 miles of this marker, measured as the crow flies. McDonald Ranch House Trinity Site (approx. 2 miles away).
Regarding Trinity Site.
This black lava obelisk marks Trinity Site ground zero, where the first atomic bomb was detonated on a 100-foot tower at 5:29:45 a.m., Mountain War Time on July 16, 1945.
Exact ground zero was the spot on the ground between the tower’s four legs – where the obelisk now stands. Although the tower was vaporized in the explosion, one of the tower’s buried footings is visible just northwest of the obelisk.
The bomb mechanism and its plutonium core were married together under the tower. The whole device was then hoisted to the top where it was protected in a small shed. There the detonators and final wiring were installed.
The Trinity device was placed on the tower to simulate an aerial blast. The Nagasaki bomb was exploded at an altitude of about 1,540 feet to maximize the blast effects. Another benefit of detonating from the tower was that less radioactive fallout was generated.
The blast vaporized the tower and some of the top soil. No bomb crater was formed because of the cushion of air provided by using the tower. The ground was depressed into a plate-like hollow about eight-feet deep and 800 yards across.
The immense heat of the explosion melted the sand, turning it into a green glass. “Trinitite,” as it was dubbed, once lined the depression.
Much of the Trinitite has been removed. The rest was bulldozed and mixed with sand. The low shed was built to protect an original section of the Trinitite-covered depression. The fences were added to control visitors.
The area inside the inner fence is still radioactive. It measures about 10 times the background radiation levels for this part of New Mexico. This means visitors standing near the obelisk receive about one half to one milliroentgens of exposure an hour. In comparison, people flying cross country in a jet airliner can receive as many as three to five milliroentgens per flight.
A little known event at Trinity was the conventional explosion used to practice the countdown procedures and calibrate instruments for the atomic test. On May 7, 1945 scientists exploded 100 tons of TNT just east of today's parking lot. Those explosives were stacked on a 20-foot wooden platform.
Also see . . . Trinity Site Time Capsule Opening Disappointing. First person review by Ben Moffett, who attended both the 1984 Time Capsule burial and its opening in October 2009. (Submitted on December 29, 2009.)
1. Time Capsule Opening
We would like to visit the Trinity Site for the opening of the Time Capsule. Will this be done in April or October of 2009?
Editor's Note: We contacted the White Sands Public Affairs Office. They've notified us that the Time Capsule will be opened during the October 2009 Trinity Site Open House. The specifics are not available at this time, so please check their link for more updated information.
— Submitted January 3, 2009, by Florence Maze of Edgewood, New Mexico.
Categories. • Military • Science & Medicine • War, World II •
More. Search the internet for Trinity Site.
Credits. This page was last revised on June 16, 2016. This page originally submitted on December 20, 2007, by Kevin W. of Stafford, Virginia. This page has been viewed 9,372 times since then and 106 times this year. Photos: 1, 2, 3, 4, 5, 6. submitted on December 20, 2007, by Kevin W. of Stafford, Virginia.