We know that there are survivors. They must be disgustingly mutated.
Flowers began to grow back in Hiroshima less than a month after Little Boy incinerated the city. But this was no comforting return of nature after humanity’s terrible flash of technological sorcery. The distorted and malformed blooms were a haunting sign that the world would never be the same again.
Both the wielders and the victims of the atom bomb knew about the lethal potential of radiation. Survivors of the blast told lurid tales of the black rain that brought radioactive sludge from the atmosphere back down to earth, and doctors recognised the low white blood cell counts of their dying patients as a symptom of something similar to an X-ray overdose. Babies who were in their mothers’ wombs at the time of the explosion were born with cruel deformities and genetic maladies.
The Americans were keen to play down the radiation story. To be fair, the radiation levels dropped rapidly after the explosion, and fears that Hiroshima might be uninhabitable for decades were swiftly proved to be unfounded. Seizing on this, the US military spin machine presented their atom bomb as just another high explosive, certainly more powerful than any yet created, but not fundamentally different from a stick of dynamite.
They maintained this stance for the best part of nine years, and for all the vague fears among the general public radiation was mostly seen by solid, no-nonsense types as a relatively minor hazard of warfare in the atomic age. Nuclear fallout was recognised and studied, but with most atomic test explosions taking place high enough off the ground to avoid drawing radiation-blasted soil up into the mushroom cloud, it didn’t seem like a major worry.
Castle Bravo changed all that. Operation Castle was the US attempt to develop a hydrogen bomb that could be practically delivered to the enemy. The preceding programme, Operation Ivy, saw the first ever explosion of a hydrogen bomb in the Ivy Mike detonation. At over ten megatons, this was more than six hundred times more powerful than the Hiroshima bomb, but as an experimental setup – a huge, cryogenically-cooled storage tank – it wasn’t something you could readily drop on Moscow. Castle Bravo swapped the cumbersome liquid deuterium that fuelled Ivy Mike’s fusion explosion for solid lithium deuteride, creating a bomb that could be readily transported – and dropped.
It was detonated on Bikini Atoll on 1 March 1954. The explosive yield was 15 megatons – three times higher than expected, thanks to an incomplete model of the fusion process. The wind had shifted eastward, blowing the radioactive fallout outside of the designated zone. The fallout plume spread out over a hundred miles, shrouding inhabited islands in radioactive dust. Most famously, the Japanese fishing vessel Daigo Fukuryu Maru was caught in the plume, radioactive coral debris raining down as white ash. Its 23 crewmen all became seriously ill, and one died. This was too big a calamity for the official US denial machine to brush aside. Along with the dreadful effects on the many islanders and fishermen subjected to this calamity, and the strain the event put on US diplomatic relations with Japan and in the wider Pacific region, Castle Bravo showed, publicly and undeniably, the far-reaching lethality of nuclear fallout from the new hydrogen bombs.
Not only would nuclear warfare devastate cities, destroy countries, turning nations to rubble in a few hours or days like World War II on fast-forward. It would also poison the soil, contaminate the sea, fill the air with lethal dust, covering the world in a deadly shroud that would linger for years – centuries – millennia. The Earth would become a dead planet.
Which brings us to Skaro.
The dead planet with its petrified forest is Terry Nation’s surreal vision of a planet long since ravaged by nuclear war. If we’re going to understand what happens to our four time travellers once they step out onto the ruined surface, we have to look at exactly why radioactivity is so bad for you.
When we talk about radiation, as in the intangible killer that blighted the survivors of Hiroshima, Castle Bravo and Skaro, we’re really talking about ionising radiation. That is, rays of light or subatomic particles that have enough energy to knock electrons out of atoms when they collide with them. This matters, because chemical processes are all about the interactions between electrons belonging to different atoms, and ionising radiation is radiation that is powerful enough to screw up chemistry. The more complicated the chemistry, the more ways there are to screw it up, and the most complicated chemical phenomenon we know about is life. So, ionising radiation is particularly relevant if you are alive, especially if you plan to stay that way.
Your body is made up of many different kinds of cells, each performing its own specialised function. The effects of ionising radiation depend not just on what kind of cell it hits, but also on whether the cell is killed outright or merely damaged. Large doses of radiation will kill a load of cells at once, leading to radiation sickness, while lower doses can damage the reproductive mechanisms of cells, causing cancers or genetic mutations. The radiation levels that we encounter on Skaro are high enough to give the time travellers acute radiation sickness, while the natives seem to only be suffering the chronic effects of mutations. Evidently cells on Skaro are made of sterner stuff than on Earth.
How susceptible a cell is to radiation damage depends mainly on how quickly it reproduces: the higher the reproduction rate, the greater the chance that the cell will be screwed up by radiation. In our bodies, blood cells reproduce quickly, nervous system cells reproduce slowly, and the cells in your gut are somewhere in between. And right enough, at low (but still damaging) levels of radiation exposure it’s the blood cells that show the first sign of damage. At this stage you just feel fatigued, though if the radiation has affected the skin there may also be sunburn, and hair loss as the hair follicles are damaged. As the dose gets higher, the damage increases and the gastrointestinal cells begin to suffer. First nausea, then vomiting and diarrhea as the dose level increases. At the highest levels, the central nervous system crumbles, leading to loss of coordination, confusion, coma, shock, convulsions – the sort of symptoms that vomiting and diarrhea seem like a blessed condition.
The lower levels of damage can be treated – blood transfusions or bone marrow transplants can provide for a full recovery from blood disorders. If the gut is too badly damaged, however, death is inevitable, and pretty nasty. And if the radiation dose is high enough to take out the central nervous system, there’s not much in the way of medical treatment beyond one last, heavy dose of morphine.
Older people will tend to be more susceptible to radiation sickness, so it’s no surprise that the Doctor is the first to succumb. We can be thankful his symptoms do not progress beyond the first stages of fatigue: the sight of Billy Hartnell shitting his guts out all over Lime Grove Studio D is not one that anyone wants to see on a Saturday teatime.
If you get your radiation dose from fallout, rather than the direct radiation blast from the explosion itself, how much damage it does depends on the precise chemical makeup of the fallout that you breath in or ingest with your food, as well as the level of radiation it gives off. In the aftermath of a nuclear war, a wide range of radioactive isotopes would be present in the fallout. Project Gabriel, a US Atomic Energy Commission study in the 1950s, determined that the most dangerous isotope would be strontium-90. This isotope emits beta radiation – fast-moving electrons – but what makes it really nasty is where it sits while it’s doing the emitting. Strontium is chemically similar to calcium – it’s directly beneath it in the periodic table – and because of this it is readily absorbed into bones, where it hangs around giving the unfortunate victim bone cancer or leukemia. It was evidence that levels of strontium-90 in children’s teeth had massively increase due to nuclear testing that convinced President Kennedy to sign the partial test-ban treaty that put an end to above-ground nuclear test explosions.
But one of the major horrors of radiation that we haven’t touched on much yet is mutation. Whether by damaging DNA molecules directly, or by upsetting the mechanisms within the cell that enable DNA to replicate, radiation can make cells and even whole organs develop in strange and unexpected ways. There is ample evidence of this kind of mutation happening in human fetuses, from Hiroshima onwards. Whether a single radiation dose can cause mutations in subsequent generations is a more vexed question. Studies of survivors of the Hiroshima and Nagasaki bombs suggest not, but laboratory studies on mice and fruitflies have found second-generation effects. In any case, to be sure of getting mutation continuing down the generations, you really need the radiation to stick around as a long-lasting environmental feature. continuing mutation effects, you need to have the radiation as a long-lasting environmental feature. The nastiest isotopes of fallout, like strontium-90 or caesium-137, decay with half-lives of the order of tens of years, so after a few generations they would be practically gone. However, there are some fallout isotopes like plutonium-239 and carbon-14 that hang around for tens of thousands of years, and are readily taken up in food and absorbed into the body. These could raise the mutation rate for a very long time indeed.
Even so, it is unlikely to produce a race of Aryan supermen in kinky pants. Most mutations are trivial, and most of the non-trivial ones are harmful. These mutations lead to cancers, genetic diseases, disabilities and severely shortened lifespans. So, although we need some mutations to drive natural selection, producing new variations that may be better suited to their environment, too high a mutation rate does not simply give us evolution on fast forward. Rather, it results in the entire population dying out before it has much chance to adapt to anything. Unless, of course, these poor, crippled mutations have the technological capability to build themselves protective cocoons with mobility and manipulation devices that allow them to survive the debilitating effects of genetic degradation. Yeah, that sounds feasible.
But there’s one last twist in the tale, when the Daleks realise they need radiation to survive. This seems an odd notion – we’ve seen how damaging ionising radiation can be to biological tissues. It is not, however, wholly without foundation. At high doses, radiation is just a bad idea and best avoided. The evidence for what effect, if any, radiation has on us at very low dose levels is sparse. If you drop a nuclear bomb on some people, and they all either die or get cancer, that’s a big effect that’s easy to measure. If you give someone a small radiation dose, and they get cancer thirty years later, separating out the effects of the dose from background radiation, passive smoking, pollution and various other carcinogens is pretty hard. So for now we have to extrapolate, and there are two main theories. One is the straightforward linear extrapolation: draw a straight line through the graph, all the way down to zero. The other is the threshold theory, which is that below a certain level of radiation there is no harm done. People involved in radiological protection argue about this a lot: the linear theory is the standard one, on which standards for radiation dose limits are based, but if the threshold theory is true then those limits are too conservative and we are throwing away money on over-cautious protection.
There is a third, rather more interesting theory. Hormesis is the phenomenon whereby a small amount of something is beneficial, while large doses are harmful. Take any household painkiller, for example – but only as directed on the packet. Since the eighties, there has been something of a cottage industry of scientists trying to establish that radiation might have a hormetic effect, through aiding DNA repair, reducing free radicals or stimulating the immune system. This theory is not widely accepted, and the opinion of official bodies ranges from cautiously interested (France) to patently unconvinced (US). So it’s possible there’s something in it, but there’s a pretty good chance it’s bollocks.
So if you do wind up as the desperate survivor of a nuclear apocalypse, horribly mutated beyond recognition, don’t count on the radiation ever doing you any good, and certainly don’t count on being able to sit around waiting to evolve into something prettier. Instead, get to work building yourself an electric wheelchair with a grabby arm and an eyestalk, and make the best of things. And it’s probably worth sticking some kind of gun on it as well. Just in case.