|
THE TRINITY TEST (Trinity Test Site, July 16, 1945)
Events
>
Dawn of the Atomic Era, 1945
-
The War Enters Its Final Phase, 1945
-
Debate Over How to Use the Bomb, Late Spring
1945
-
The Trinity Test, July 16, 1945
-
Safety and the Trinity Test, July 1945
-
Evaluations of Trinity, July 1945
-
Potsdam and the Final Decision to Bomb, July
1945
-
The Atomic Bombing of Hiroshima, August 6,
1945
-
The Atomic Bombing of Nagasaki, August 9,
1945
-
Japan Surrenders, August 10-15, 1945
-
The Manhattan Project and the Second World War,
1939-1945
Until the atomic bomb could be tested, doubt would remain
about its effectiveness. The world had never seen a
nuclear explosion before, and estimates varied widely on
how much energy would be released. Some
scientists at
Los Alamos continued privately to have
doubts that it would work at all. There was only
enough weapons-grade uranium available for one bomb, and
confidence in the gun-type design was
high, so on July 14, 1945, most of the uranium bomb
("Little Boy") began its trip westward to the Pacific
without its design having ever been fully tested. A
test of the plutonium bomb seemed vital, however, both to
confirm its novel implosion design and to
gather data on nuclear explosions in general.
Several plutonium bombs were now "in the pipeline" and
would be available over the next few weeks and
months. It was therefore decided to test one of
these.
Robert Oppenheimer chose to name this
the "Trinity" test, a name inspired by the poems of John
Donne. The site chosen was a remote
corner on the Alamagordo Bombing Range known as the
"Jornada del Muerto," or "Journey of Death," 210 miles
south of Los Alamos. The elaborate instrumentation
surrounding the site was tested with an explosion of a
large amount of conventional explosives on May 7.
Preparations continued throughout May and June and were
complete by the beginning of July. Three observation
bunkers located 10,000 yards north, west, and south
(right) of the firing tower at ground zero would attempt
to measure key aspects of the reaction.
Specifically, scientists would try to determine the
symmetry of the implosion and the amount of energy
released. Additional measurements would be taken to
determine damage estimates, and equipment would record the
behavior of the fireball. The
biggest concern was
control of the radioactivity the test device would
release. Not entirely content to trust favorable
meteorological conditions to carry the radioactivity into
the upper atmosphere, the Army stood ready to evacuate the
people in surrounding areas.
On July 12, the plutonium core was taken to the
test area in an army sedan (left). The non-nuclear
components left for the test site at 12:01 a.m., Friday
the 13th. During the day on the 13th, final assembly
of the "Gadget" (as it was nicknamed) took place in the
McDonald ranch house. By 5:00 p.m. on the 15th, the
device had been assembled and hoisted atop the 100-foot
firing tower. Leslie Groves,
Vannevar Bush,
James Conant,
Ernest Lawrence, Thomas Farrell,
James Chadwick, and others arrived in the
test area, where it was pouring rain.
Groves and Oppenheimer, standing at the S-10,000 control
bunker, discussed what to do if the weather did not break
in time for the scheduled 4:00 a.m. test. To break
the tension, Fermi began offering anyone listening a wager
on "whether or not the bomb would ignite the atmosphere,
and if so, whether it would merely destroy New Mexico or
destroy the world." Oppenheimer himself had bet ten
dollars against George Kistiakowsky's entire month's pay
that the bomb would not work at all. Meanwhile,
Edward Teller was making everyone nervous by applying
liberal amounts of sunscreen in the pre-dawn darkness and
offering to pass it around. At 3:30, Groves and
Oppenheimer pushed the time back to 5:30. At 4:00, the
rain stopped. Kistiakowsky and his team armed the device
shortly after 5:00 and retreated to S-10,000. In
accordance with his policy that each observe from
different locations in case of an accident, Groves left
Oppenheimer and joined Bush and Conant at base camp.
Those in shelters heard the countdown over the public
address system, while observers at base camp picked it up
on an FM radio signal.
During the final seconds, most observers laid down on the
ground with their feet facing the Trinity site and simply
waited. As the countdown approached one minute,
Isidore Rabi said to the man lying next to him, Kenneth
Griesen, "Aren't you nervous?" "Nope" was Griesen's
reply. As Groves later wrote, "As I lay there in the
final seconds, I thought only of what I would do if the
countdown got to zero and nothing happened." Conant
said he never knew seconds could be so long. As the
countdown reached 10 seconds, Griesen suddenly blurted out
to his neighbor Rabi, "Now I'm scared." Three, two,
one, and Sam Allison cried out, "Now!"
At precisely 5:30 a.m. on Monday, July 16, 1945, the
nuclear age began. While Manhattan Project staff members
watched anxiously, the device exploded over the New Mexico
desert, vaporizing the tower and turning the asphalt
around the base of the tower to green sand. Seconds
after the explosion came a huge
blast wave and
heat searing out across the desert.
No one could see the radiation generated
by the explosion, but they all knew it was there.
The steel container "Jumbo," weighing over 200 tons and
transported to the desert only to be eliminated from the
test, was knocked ajar even though it stood half a mile
from ground zero. As the orange and yellow fireball
stretched up and spread, a second column, narrower than
the first, rose and flattened into a mushroom shape, thus
providing the atomic age with a visual image that has
become imprinted on the human consciousness as a symbol of
power and awesome destruction.
The most common immediate
reactions to the explosion were surprise, joy, and
relief. Lawrence was stepping from his car when, in
his words, everything went "from darkness to brilliant
sunshine in an instant"; he was "momentarily stunned by
the surprise." (Click here to read Lawrence's thoughts on the Trinity
test.) A military man was heard to exclaim, "The long-hairs
have let it get away from them!" Hans Bethe , who
had been looking directly at the explosion, was completely
blinded for almost half a minute. Norris Bradbury
reported that "the atom bomb did not fit into any
preconceptions possessed by anybody." The blast wave
knocked Kistiakowsky (who was over five miles away) to the
ground. He quickly scrambled to his feet and slapped
Oppenheimer on the back, saying, "Oppie, you owe me ten
dollars." The physicist Victor Weisskopf reported that
"our first feeling was one of elation." The word
Isidor Rabi used was "jubilant." Within minutes,
Rabi was passing around a bottle of whiskey. At base
camp, Bush, Conant, and Groves shook hands. Rabi
reported watching Oppenheimer arrive at base camp after
the test:
You've seen pictures of Robert's hat. And he came to where
we were in the headquarters, so to speak. And his
walk was like "High Noon" -- I think it's the best I could
describe it -- this kind of strut. He'd done it.
When they met, Groves said to Oppenheimer, "I am proud of
you." Groves's assistant, Thomas Farrell, remarked
to his boss that "the war is over," to which Groves
replied, "Yes, after we drop two bombs on Japan." (Click here to read Groves's observations of the
Trinity test [pdf].) Probably the most mundane response of all was Fermi's:
he had calculated ahead of time how far the blast wave
might displace small pieces of paper released into
it. About 40 seconds after the explosion, Fermi
stood, sprinkled his pre-prepared slips of paper into the
atomic wind, and estimated from their deflection that the
test had released energy equivalent to 10,000 tons of
TNT. The actual result as it was finally calculated
-- 21,000 tons (21 kilotons) -- was more than twice what
Fermi had estimated with this experiment and
four times as much as had been predicted by most
at Los Alamos.
Soon shock and euphoria gave way to more sober
reflections. Rabi reported that after the initial
euphoria, a chill soon set in on those present. The
test director, Kenneth Bainbridge, called the explosion a
"foul and awesome display" and remarked to Oppenheimer,
"Now we are all sons of bitches." Expressions of
horror and remorse are especially common in the later
writings of those who were present. Oppenheimer
wrote that the experience called to his mind the legend of
Prometheus, punished by Zeus for giving man fire, and said
also that he thought fleetingly of Alfred Nobel's vain
hope that dynamite would end wars. Most famously,
Oppenheimer later recalled that the explosion had reminded
him of a line from the Hindu holy text, the
Bhagavad-Gita: "Now I am become Death, the
destroyer of worlds." The terrifying destructive power of
atomic weapons and the uses to which they might be put
were to haunt many of the
Manhattan Project scientists for the
remainder of their lives.
The success of the Trinity test meant that both types of
bombs -- the uranium design, untested but thought to be
reliable, and the plutonium design, which had just been
tested successfully -- were now available for use in the
war against Japan. Little Boy, the uranium bomb, was
dropped first at
Hiroshima on August 6, while the plutonium
weapon, Fat Man, followed three days later at
Nagasaki on August 9. Within days,
Japan offered to surrender.
-
The War Enters Its Final Phase, 1945
-
Debate Over How to Use the Bomb, Late Spring
1945
-
The Trinity Test, July 16, 1945
-
Safety and the Trinity Test, July 1945
-
Evaluations of Trinity, July 1945
-
Potsdam and the Final Decision to Bomb, July
1945
-
The Atomic Bombing of Hiroshima, August 6,
1945
-
The Atomic Bombing of Nagasaki, August 9,
1945
-
Japan Surrenders, August 10-15, 1945
-
The Manhattan Project and the Second World War,
1939-1945
Previous Next
Sources and notes for this page.
The text for this page was adapted from, and portions
were taken directly from the
Office of History and Heritage Resources
publication:
F. G. Gosling,
The Manhattan Project: Making the Atomic Bomb
(DOE/MA-0001; Washington: History Division, Department
of Energy, January 1999), 48-49. On the availability of additional
plutonium bombs (but not uranium), see "The Manhattan Engineer District, 1945-1946." The "long-hairs" remark is quoted in
Los Alamos Scientific Laboratory,
Los Alamos: Beginning of an Era, 1943-1945
(Los Alamos: Public Relations Office, Los Alamos
Scientific Laboratory, ca. 1967-1971), 53; the anecdotes re the final seconds of the
countdown are from
Los Alamos: Beginning of an Era,
50-51. Click
here for information on the color photograph of
Trinity. The photograph of SED Herb Lehr holding the
Gadget's core is courtesy the
Los Alamos National Laboratory (LANL)
and is reprinted in Rachel Fermi and Esther Samra,
Picturing the Bomb: Photographs from the Secret World
of the Manhattan Project (New York: Harry N. Abrams, Inc., Publishers, 1995),
138. The following pictures are also courtesy
LANL: the bunker at S-10,000, the plutonium core being
unloaded from the car,
the gadget being hoisted up the tower, the
unidentified man sitting next to the gadget, and the
photograph of Kenneth Bainbridge. The map of the
Trinity Test Site is reproduced from
Vincent C. Jones,
Manhattan: The Army and the Atomic Bomb,
United States Army in World War II (Washington: Center
of Military History, United States Army, 1988),
479. The photograph of
Robert Oppenheimer with
Leslie Groves at the Trinity Site
appears on the cover of the History Office
publication:
The Signature Facilities of the Manhattan
Project
(Washington: History Division, Department of Energy,
2001). The photograph of Fat Man is
courtesy the U.S. Army Corps of Engineers (via the
National Archives).
Home |
History Office
|
OpenNet
|
DOE
|
Privacy and Security Notices
About this Site
|
How to Navigate this Site
|
Note on Sources
|
Site Map
|
Contact Us
|