The images in this book show U.S. atomic detonations from the era of above-ground nuclear testing, which lasted from July 16, 1945 to November 4, 1962.  In that time, the United States conducted 216 nuclear tests in the atmosphere and oceans, and the Soviet Union conducted 217.  After both countries signed the Limited Test Ban Treaty on August 5, 1963, nuclear testing in the atmosphere, the oceans, and cosmic space ceased.  Thereafter, both nations vigorously pursued nuclear testing underground.  The United States would go on to perform a total of 1054 nuclear tests, involving 1149 separate explosions, until its last test occurred on September 23, 1992.  The Soviet Union would conduct a total of 715 tests, involving 969 separate explosions, until its last test event on October 24, 1990.  That nation would formally dissolve 13 months later.

Since their inception, nuclear weapons have been used twice in combat.  On August 6, 1945, the United States dropped a bomb with a yield of 15 kilotons -- the destructive force of 15,000 tons of TNT -- on the Japanese city of Hiroshima, eventually killing over 200,000 people.  Three days later the United States destroyed the Japanese city of Nagasaki with a bomb yielding 21 kilotons; over 60,000 people would eventually die.  Japan agreed to unconditional surrender five days later, and World War II ended shortly thereafter.

A nuclear weapon is a device in which explosive energy is derived from either fission, fusion, or a combination of the two.  Nuclear fission is the splitting of the nucleus of a large atom into two or more parts, and was first demonstrated in an explosive device in 1945 with the Trinity test, which yielded 21 kilotons.  When bombarded by neutrons, some atoms of extremely heavy elements – such as those of the isotope uranium-235, which forms about 0.7% of naturally occurring uranium, and those of plutonium-239, which does not occur naturally and is instead made in nuclear reactors – will fall apart. This fission releases lighter nuclei, energy and neutrons, and the neutrons produced can then go on to split further atoms in an ever-increasing chain reaction.  Nuclear fusion is the forcing together of the nuclei of two light atoms to create a third, and was first demonstrated in an explosive device in 1952 with the Mike test.  Mike yielded 10,400 kilotons, or 10.4 megatons, of energy, 500 times the power of Trinity and more than that released in all the explosions of both World Wars combined.  To create the conditions under which deuterium and tritium, which are heavy isotopes of hydrogen, will fuse to form helium requires conditions of extreme heat and pressure that can only be achieved by using a first fission explosion as an “initiator”.  These hydrogen bombs, or thermonuclear weapons, thus come in two stages, with fission components triggering fusion components.  In some designs a third stage, in which neutrons from the fusion set off yet more fission, is added

Fission and fusion differ in the amount of energy that they release. Splitting every atom in one gram of uranium-235 would release 12.5 million times more energy than would be given off by a gram of ordinary chemical explosive; fusing one gram of deuterium into helium would release eight times more energy still.  A further difference between fission and fusion explosions is that the former are self-limiting.  Fission depends on the assembly of a “critical mass” in which there are enough atoms, closely enough compressed, for a chain reaction to get underway.  The subsequent explosion quickly disassembles this critical mass, and the fission reactions thus cease.  For this reason the largest fission devices – which are “boosted” with the addition of some heavy hydrogen – have a maximum yield of about one megaton.  A true fusion explosion does not depend on a critical mass in the same way; it will burn as brightly and as long as it has access to thermonuclear fuel.  That there are no inherent upper physical limits to the size of a fusion explosion is demonstrated by the stars, thermonuclear furnaces thousands and millions times larger than the earth.

A nuclear explosion creates damaging heat and blast effects like those of a conventional explosion, though on a far greater scale.  In a hundred-millionth of a second, the temperature at its core builds to several hundred million degrees, many times the temperature of the center of the Sun, and pressures reach a hundred million atmospheres, creating initial expansion speeds of about five million miles an hour.  But a nuclear explosion also transforms the very fabric of matter, producing gamma-rays, X-rays and radio waves as well as neutrons, alpha particles and beta particles.  All this radiation is undetectable by human senses and some of the emissions -- X-rays, gamma-rays, and neutrons in particular -- can penetrate living tissue and alter the delicate structure of its cells.  In some cases this radiation will kill cells outright, in some cases it will damage in a way that can be coped with and repaired, and in some cases it will damage their genetic material so that the cells go on to reproduce imperfectly and without check.  This last possibility is the one that causes cancer, sometimes relatively quickly after exposure to the radiation, sometimes decades thereafter.

As well as releasing vast amounts of energy, nuclear devices also create a host of unstable radioactive isotopes, both by burning their own nuclear fuel and by irradiating material close to the explosion.  These unstable isotopes will eventually decay into stable isotopes; the radiation they give off is part of this process. The rate of decay is defined by the isotope’s “half life” – the time it takes for half a given amount of the material to decay.  Some radioactive isotopes have half lives of seconds, some of years, some of centuries.  Thus the invisible legacy of a nuclear explosion can linger long after detonation, both in the environment at large and in the bodies of living things.

This radioactive aftermath can be spread out in space, as well as time.  The term “fallout” refers to the return to earth of radioactive matter which has been lifted into the atmosphere by a nuclear detonation, as well as the matter itself once it is deposited on the ground, vegetation, structures, or a body of water.  Detonations which occur very high in the atmosphere or underground produce little or no fallout, while those occurring near the surface of the earth produce a great deal, as vast quantities of dirt, dust and smoke are thrown into the air by the blast and irradiated.  Depending on the prevailing winds, the radioactive debris cloud of a nuclear detonation can travel for hundreds and even thousands of miles, sprinkling the earth evenly with fallout or concentrating in “hot spots” caused by rain or snow bringing many radioactive particles down at once.

Some radioactive fission isotopes are more dangerous to humans than others.  Within the first month, the most harmful are iodine-131, with a half-life of 8 days, and strontium-89, with a half-life of 54 days.  Longer term, strontium-90, with a half-life of 25 years, and cesium-137, with a half-life of 33 years, are the greatest hazards.  The body treats radioactive iodine and cesium the same way it processes regular iodine and potassium,  so they concentrate in the same organs, particularly the thyroid, where cancers are likely to form.  Infants and children are particularly at risk, since the milk of cows that have grazed on fallout-covered pasture will contain the dangerous isotopes in concentrated form.  Similarly, the body treats radioactive isotopes of strontium as if they were normal calcium, passing them to the bone and marrow, where they are likely to cause leukemia.

Of the 216 atmospheric tests detonated by the United States, 106 of them occurred continentally at the Nevada Test Site, 63 miles from Las Vegas.  The footprint of harmful radioactive fallout from those detonations flowed generally to the east and northeast of the test site, often extending the length of the nation and occasionally into the Atlantic Ocean beyond.  Those areas immediately east and north of the test site in Nevada and Utah were hardest hit throughout the 1950s and early 1960s, though the U.S. government attempted to minimize public perception of the danger through a systematic campaign of propaganda and intimidation.  Finally realizing the full extent of the adverse health effects they suffered from continental tests, “downwinder” residents of these areas organized in the 1970s, and by the early 1990s had extracted a formal apology from Washington, as well as ongoing monetary compensation for a host of fallout-related cancers.

From 1951 to 1957 at the Nevada Test Site, U.S. military troops, primarily from the Army, were ordered to observe nuclear tests at varying distances from the blast point, and then conduct “atomic war exercises”  at or near ground zero immediately after detonation.  Sometimes they were placed in trenches as close as 1.8 miles away.  While the personnel safety guidelines of the Atomic Energy Commission -- the civilian agency in charge of United States nuclear matters -- required a distance of 7 miles from the blast, the U.S. military quickly bypassed them in its quest to create “hardened” troops capable of “tactical” warfare on the atomic battlefield.  Many nuclear test veterans contracted fatal cancers and died; those that survived long enough to organize, like downwinder residents, would receive official governmental recognition of their plight and monetary compensation beginning in 1988.

While the U.S. military did not conduct troop exercises during the higher-yielding nuclear tests conducted at isolated atolls and islands in the Pacific from 1946 to 1962, the human cost of the tests was, and continues to be, steep.  Indigenous islanders were uprooted without recourse from test site areas initially, and several tests greatly exceeded expected yields, creating intense and unexpected radiological disasters.  Of these, the 15-megaton 1954 Bravo test at Bikini Atoll in the Marshall Islands was the worst, badly sickening test personnel, relocated islanders nearby, and the crew of a Japanese fishing vessel 85 miles away from the blast.  Repeated large-scale testing has also resulted in enduring radiological contamination of all the test islands, including Enewetak Atoll and Johnson and Christmas Islands.  Bikini remains uninhabitable to this day, its soil contaminated with radioactive cesium-137 that concentrates in fruits and vegetables.  Like the Nevada downwinders, the Bikinians organized and eventually sued the United States for damages; in 1982 the U.S. established three trust funds for environmental restoration and reparations, also creating a fund for the restoration of the southern islands of Enewetak Atoll as well.  Enewetak has been successfully restored and  resettled.  In 1988 the United States established a Marshallese Nuclear Tribunal to compensate radiation victims, and more than 1000 islanders have received damages.

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The photographs in 100 SUNS depict U.S. nuclear tests at or near the moment of detonation, and most were declassified by the U.S. government shortly after test completion.  The United States usually announced atmospheric tests in advance, and images that did not reveal the size, shape, weight or inner workings of a nuclear device were released to the public, often to underscore to domestic and international audiences the power or innovation of a particular test.  Most of the images seen here were obtained from prints at the U.S. National Archives, with a few gleaned from the records of the Los Alamos National Laboratory.  They have been reproduced here with faithfulness to the appearance of the particular print.

Each of the 1054 U.S. nuclear tests was given a code-name by either the U.S. military or the Atomic Energy Commission.  Names were initially based on the military phonetic alphabet (Able, Baker, Charlie, and so forth), but quickly branched out into more arbitrary and eclectic nomenclature to avoid duplication and confusion.  Test names were never indicative of the nature of the actual classified nuclear device or weapon at hand.

While 22 images in this book were made by photographers in the U.S .Army Signal Corps, most are the work of the 1352nd Photographic Group of the U.S. Air Force.  From 1947 to 1969, the 1352nd Photographic Group was based at an extensive motion picture and still photographic facility in Hollywood, California called the Lookout Mountain Air Force Station.  Lookout Mountain was thus in a position to draw on the world’s best film technology and its largest relevant talent pool, while protecting top-secret classified military information in a dedicated, essentially clandestine complex.

The Station was charged with photographing and filming all aspects of U.S. nuclear tests at the Nevada Test Site and the offshore Pacific Proving Grounds.  Using onsite studio and lab facilities, Lookout’s civilian and military staff also produced over 6500 scientific, technical, training and informational films for the Air Force, Department of Civil Defense, Atomic Energy Commission, and other U.S. government agencies.  Some were released early on as propaganda; many are still classified.

The Lookout Mountain cameramen generated vast amounts of visual documentation of each test, bringing their manned cameras as close as 4 miles to the point of detonation in Nevada and operating remotely-controlled ones closer.  During the much larger Pacific tests, they kept their manned cameras a minimum of 20 miles from the blast point.  Aside from recording history, their photographic work was integral to scientific investigation of the tests.  Measuring the yield of a detonation, for example, was done three ways: by “bang-meters” on the ground, by multiple cameras filming throughout, and – most accurately – by radiochemical analysis.

Only a small fraction of the extensive documentation of nuclear tests by Lookout Mountain and the Army Signal Corps can now be found in publicly-accessible U.S. government archives.  It is not the purpose of this work to try and locate that hidden mass of material, much of which may have been lost, deliberately destroyed, or remain classified.  In some ways, however, the archive images that are available do speak more to absence than to presence.  One cannot help but wonder what as citizens we still do not know about the subject of nuclear weapons, not only in the sense of the surreal excesses of the cold war past, but in terms of the hidden, weaponized nuclear present that will be with us for as long as we know time.

While eliminating the global specter of radioactive fallout and perhaps somewhat moderating the nuclear saber-rattling of nations, the shift to exclusively underground testing brought about by the 1963 Limited Test Ban Treaty came at a paradoxically high price: cultural invisibility and secrecy.  The United States has detonated four times as many nuclear detonations underground as it has above.  In all of these underground tests, there has been little to see and little to photograph; there is no record that helps keep an informed citizenry viscerally aware of what its government is doing.  While the world is currently not locked in a nuclear arms race between superpowers that in hindsight can only be described as kind of state-level psychosis, these “weapons of mass destruction” are with us forever.  Their proliferation continues apace, and they are held in the world’s most redundant numbers by the United States of America. 

It is difficult to comprehend the mechanics and effects of just one such distillation of brilliant human savagery, much less the some hundred thousand nuclear weapons that have been fabricated by nations since the Trinity test.  Any conscious person instinctively turns away.  That is why these photographic images from the era of atmospheric nuclear detonation remain utterly relevant, beyond the historic interest of the extreme cultural moment they capture.  Photographs only tell us about the surface of things, about how things look.  When it’s all we have, however, it’s enough to help understanding.  It exists.  It happened.  It is happening.  May no further nuclear detonation photographs be made, ever.

-- © Michael Light, 2003