Read Armageddon Science Online
Authors: Brian Clegg
In that time, the islanders began to develop symptoms of radiation poisoning from that seemingly harmless snowlike deposit that had formed on the island. In a typical response to radiation, ugly burns appeared on their skin. The victims began to vomit and suffer from diarrhea. Hair came out in chunks, and some islanders were coughing up blood.
For many, the hydrogen bomb was the ultimate example of humanity’s destructiveness—a horrible and frightening deliverer of overkill. Teller, however, remained in love with the concept that had won him over in 1942, and for the rest of his life pressed for applications of thermonuclear devices for everything from mining to diverting asteroids that were on a collision course with Earth. He infamously dismissed concerns about fallout from the tests of hydrogen bombs, commenting that the risk was no worse than being “an ounce overweight.” Charitably, we can assume he didn’t know about Rongelap.
In the arms race that followed the first successful thermonuclear explosion, bigger and bigger bombs were developed. This demonstrated the truly terrifying nature of fusion devices—there is no theoretical limit to the size of explosion they can deliver. The largest ever exploded was a Soviet bomb tested on October 30, 1961, which was the equivalent of 58 million tons of TNT. Vast stocks of nuclear weapons were built up. The U.S. military had not forgotten Pearl Harbor, and assumed that an unprovoked attack from the Soviet Union could result in the majority of its weapons being destroyed. For this reason it stockpiled one hundred times as many weapons as were considered necessary to wipe out America’s enemies. It was hoped that if the Soviets knew that there would always be enough weapons to destroy them, they would never make that first strike.
By the late 1950s Britain had also successfully tested a thermonuclear weapon, and China and France were to follow. Other nations such as India, Pakistan, and Israel have followed in the nuclear route, though Israel’s stock is limited to fission weapons, and it is not clear exactly what capability India and Pakistan have available. Thousands of nuclear weapons have been accumulated.
Even today, fission bombs have not gone out of fashion, as thermonuclear devices will always be relatively unwieldy, but the more recent fission weapons are something of a hybrid. Conventional fission weapons of the kind used at Hiroshima and Nagasaki have a practical limit of around fifty kilotons—two to three times the power of the Japanese bombs—but this can be enhanced by a factor of ten using a technique known as boosting.
The fission chain reaction is limited by the number of neutrons of the right speed that can be pumped into the fissile material. In a boosted weapon, the standard neutrons from the fission process are added to by neutrons being generated in a small fusion reaction. A small amount of fusible material like deuterium is injected into the heart of the bomb. This undergoes nuclear fusion in the explosion, generating extra neutrons to boost the fission reaction. Because it’s only a small amount; there is no need for all the sophisticated mechanism necessary to get a true fusion bomb to work—this is just a turbocharger for the conventional fission reaction. Where a modern atomic stockpile contains fission weapons, they are like to be such boosted devices.
There are inevitably a range of reasons why states have entered the nuclear club. For some, like Israel, it seems to have been as a result of perceived threat. As a small country, surrounded by enemies, it seemed to the Israeli state that the deterrent power of nuclear weapons was necessary—although the continued terrorist attacks since Israel acquired its nuclear capability seem to emphasize that nuclear weapons deter only states themselves capable of making nuclear attacks, as those attacking Israel have assumed that a conventional attack will not produce nuclear retaliation.
Others, like North Korea, seem to be aiming more for status than to deal with any perceived threat. The term “nuclear club” has a suggestion of us and them, the elite and the hoi polloi. It’s easy from within a country that has a nuclear capability to dismiss this need for status as insignificant, but there is a real sense of “Why should they have it when we don’t?” It’s no coincidence that the permanent members of the UN Security Council all have nuclear weapons. Membership in the club is a badge of power.
At the time of writing, as the aftermath of the 2008 recession continues to have an effect, many in countries like Britain and France are questioning whether it is financially acceptable to maintain a nuclear deterrent, particularly where conventional military forces have been stretched by actions in Iraq and Afghanistan. Britain, particularly, has had huge debates over whether it should renew the Trident nuclear submarine program. Yet financial arguments about military benefits miss the point. Maintaining a nuclear capability is not primarily a military action, but a political one. Having nuclear weapons is about international prestige, about being
someone
in the family of nations.
Arguably this is mad politics rather than mad science. Once the science was established, there was a clear opportunity for the politicians to control atomic power for worldwide good—but political fear or political necessity (depending on your viewpoint) made this dream impossible to realize. Despite the reduction in tension since the fall of the Soviet Union, and the significant reductions in numbers of weapons under the Strategic Offensive Reductions Treaty, the world still has a huge and deadly arsenal of nuclear warheads that could readily devastate civilization should they ever be used. It’s no accident that the initials of the term to describe the standoff of nuclear powers, mutually assured destruction, spell the word they do.
Yet for all the devastating might of current nuclear arsenals, it’s easy to forget that we have not gone as far as we could have. In the 1950s, something even more terrifying was predicted. There was every expectation that bombs would be constructed that would not just take out a major city like the thermonuclear weapons of the time, but that could wipe out all life on Earth: a true no-holds-barred doomsday weapon. This hypothetical weapon was sometimes called the C-bomb.
Although the idea had been discussed among the atomic cognoscenti before a single nuclear weapon had been dropped in anger, the doomsday weapon’s public unveiling was on an NBC radio show on February 26, 1950. Remarkably popular in an age where intellectual content was still considered appropriate for mass audience broadcasts, this was the
University of Chicago Round Table,
where leading figures would debate a topic of the day.
The subject for this particular discussion was nuclear weapons, and Hans Bethe, one of the lead scientists on the Manhattan Project, warned listeners that one of the worst aspects of the hydrogen bomb was the radiation it could produce. It could, he said, pump radioactive carbon 14 into the atmosphere that would remain a hazard for five thousand years. With enough thermonuclear weapons, the radioactive blanket produced could make life on the planet impossible. But Bethe was to be trumped by Hungarian-born American scientist Leo Szilard, the man who had conceived of the chain reaction, and who made major contributions to the theory behind the atomic weapon. He warned that everything that had been envisaged to date—including hydrogen bombs—could soon be outclassed.
A conventional nuclear weapon caused most of its destruction by its explosion, shock wave, and heat. But as Bethe had described, there was also a more insidious devastation from the radioactive fallout—the longer-term impact of the radioactive residue, spread into the atmosphere by the explosion, causing radiation sickness and death. In the discussion, Szilard imagined a nuclear device where this radioactive side effect would be magnified by encasing a conventional bomb in a jacket of a material that readily absorbed radiation.
This jacket would be vaporized by the explosion, while at the same time the material it was constructed from would be transformed into a highly radioactive form. As the explosion drove the remains of the jacket high into the atmosphere it would spread fine radioactive dust over hundreds or even thousands of miles. With the right material—Szilard suggested the element cobalt would be ideal for the job—this could wipe out whole continents, or even end the life of the whole world.
The model for the way such a bomb would spread dust around the world by first pumping it into the high atmosphere was not any of the bomb tests that had happened in the years leading up to Szilard’s remarks on the broadcast. Instead, it was an event that shook the world—literally—on August 26, 1883. It was then that the volcanic island Krakatoa most famously erupted.
Portrayed in the wonderfully inaccurate movie
Krakatoa, East of Java
(Krakatoa is, in fact, west of Java), the volcanic island known locally as Krakatau had seen a number of earlier eruptions, with events recorded as early as AD 416, but the 1883 eruption was massive, producing an explosive power equivalent to a two-hundred-megaton bomb. The significance of this eruption for the bomb makers was not the impact of that explosion, though. It was its ability to spread material around the world.
Around twenty cubic kilometers (four and three-quarter cubic miles) of ash and rock were spewed out by the explosion. Just think of that for a moment—a cube of material nearly five miles on each side. This ash was thrown up eighty kilometers (fifty miles) into the atmosphere and traveled around the Earth, following the eruption’s shock wave, which was measured passing around the globe a total of seven times. The result of the dark ash suspended in the atmosphere getting in the way of sunlight was to reduce global temperatures by around one degree Celsius (two degrees Fahrenheit) and to disrupt weather patterns for several years. The ash was detected everywhere around the world. Now substitute for that ash the deadly radioactive fallout of a cobalt bomb and you have Szilard’s doomsday weapon.
With a half-life of around five years, the isotope cobalt 60 would have plenty of time to spread around the world, pumping out deadly gamma rays. The impact would be inescapable—there would be nowhere to hide. Such a bomb (or more likely a series of bombs) would need to be much larger than anything that had ever been made. It couldn’t be dropped from an aircraft. But it was quite conceivable for such a bomb to take the form of a ship—and the nature of the devastation was such that it would not have to be set off at a particular location.
When Szilard dreamed up this hypothetical weapon, he was aware that there was an obvious question to be answered. Why would anyone other than a madman want such a weapon? Who would want to wipe out all life on Earth? The answer, he suggested, was someone looking for the ultimate in deterrence. If a country was threatened by an enemy with attack, particularly an attack with nuclear weapons, that country could say, “Stop, come no further. If you do, we will destroy the world.” As the chairman of the University of Chicago panel pointed out on that radio show, the terrible reality of this kind of weapon is that it would be easier to destroy all life with it than it would be to use the technology to attack an enemy in a controlled way.
While Szilard wasn’t sure any existing power would consciously wipe out life from the Earth, he did believe that both the United States and the Soviet Union would be prepared to make such a threat and to construct the means to make the threat meaningful—and if they ever reached a standoff on the use of the doomsday weapon, it was not impossible to imagine them carrying out the threat. Others pointed out that it was quite feasible that a man like Hitler, had he controlled such a weapon, might well have been prepared to use it at the end, when it was obvious that he had lost the war. It does not seem at all fanciful that, unable to control the world, he would have tried to destroy all life on Earth.
Although the idea of a cobalt bomb immediately took on a terrible reality in the mind of the general public, it was only a piece of speculation on Szilard’s part when the broadcast was made in 1950. Even so it would reinforce the fear that had already been generated by the dropping of the atomic bomb and that was stoked up by the existence of the hydrogen bomb. This feeling is typified in Tom Lehrer’s darkly humorous song “We Will All Go Together When We Go.”
The practicality of Szilard’s idea was to be given support by other scientists when they worked through the numbers. Admittedly, a doomsday cobalt attack would require something immense—much larger than any atomic weapon that had ever been constructed. It would require thousands of tons of cobalt alone. Yet there was no theoretical limit to the size of a hydrogen bomb—and there was nothing to stop a cobalt doomsday device being made up of a series of ships or land-based sites enabling any size of bomb to be made.
Even though such a bomb was never built, the idea of using radiation as a deadly carpet, rather like the salt that is used in the Bible to seed fields to stop anything from growing, was already in the minds of the public and the military alike. In 1950, in the first year of the Korean War, General Douglas MacArthur proposed following up a defeat of Communist Chinese troops by using radioactive cobalt 60 to produce a five-mile-wide no-go zone between Korea and China making it impossible to pass from one country to the other—the ultimate border control.
MacArthur believed that he had the Communists “in the palm of his hand” and would have been able to crush them by using this tactic had it not been for a combination of harassment and interference from the government in Washington, and the “perfidy” of the British, who MacArthur believed had informed the Chinese of his intentions after being briefed by Washington. Whatever the reasoning, thankfully, the plan to sow a cobalt barrier was never undertaken.
During the cold war, our biggest fear was the outbreak of nuclear war. It was thought that it would bring the end of civilization as we knew it, with only pockets of human survivors expected in the United States, the Soviet Union, and Europe. As far as has been revealed, the closest this came to occurring took place in October 1962, during the Cuban missile crisis. After a spy plane noted a new military site on Cuba, it soon became clear that the Soviets were installing missiles on the island that would be capable of reaching key U.S. cities in minutes.