The Science of Battlestar Galactica

by Di Justo, Patrick

  We’ve established that ionizing radiation can cause mutations within multicellular organisms, and that some of those mutations can be passed along to subsequent generations of cells. It turns out that if the cellular mutation occurs within the reproductive system of the affected organism, mutations can be passed along to descendants. More often than not, this is manifested as deformities—extra or misplaced limbs, albinism, missing organs, and the like. Maybe the old movies about mutant ants, grasshoppers, and spiders weren’t so totally far-fetched after all.

  THROW ’EM OUT THE AIRLOCK

  There are a lot of boards on the Internet where fans can discuss their favorite television shows. They’re places to praise a particularly good episode, or to pan a lame one. One of the Battlestar Galactica episodes fans took particular issue with was the third season’s “A Day in the Life.”

  Chief Tyrol had to fix a slow leak in a battle-damaged airlock. Because he saw an opportunity to spend some “quality time” (or what passes for quality time to a fleet on the run) with his wife, he assigned Cally to assist him. While the couple was working in the airlock, a malfunction triggered the inner airlock door to close, trapping the Tyrols with a slowly dwindling air supply as well as the prospect that their son, Nicky, might be a parent or two shy by day’s end.

  Apollo’s plan to save the Chief and Cally is to blow the explosive bolts on the outer airlock door. Explosive decompression of the remaining air in the airlock should then expel the Tyrols out of Galactica through space and into the open hatch of a waiting Raptor. They’ll repressurize the Raptor, and then deal with the physiological effects on the Tyrols.

  Cally and Galen Tyrol in “A Day in the Life.”

  I honestly beleave it iz better tew know nothing than two know what ain’t so.

  —Josh Billings Affurisms (1865)

  The ambient temperature of space is not absolute zero. It is almost absolute zero. In the absence of a nearby star or other heat-producing object, space is about 2.7 Kelvins, or about minus 455 degrees Fahrenheit. If Cally’s temperature is about 98 degrees F, then there is a more than 500-Fahrenheit-degree temperature difference between her body and space. There should be a lot of heat transfer going on, right? The laws of thermodynamics state that heat should flow from the hotter material (Cally) to the colder material (space) until both materials are the same temperature. Since there is a lot more of space than there is of Cally, every last bit of heat should be drained out of her, and both she and the Chief (who is a bit bulkier, but still tiny compared to the universe) should freeze solid pretty quickly, right?

  Not so fast. There are three primary methods of heat transfer: convection, conduction, and radiation. Convection occurs only when a fluid is heated from beneath, such as a pot of water on the stove, or deep within stars and planetary interiors, so it’s not relevant to our discussion of the Tyrols.

  Conduction, the temperature equalization that occurs when two objects of differing temperatures are in contact, is the method of heat transfer we’re most familiar with in our everyday lives. When you touch a hot stove with your finger, energy is conducted from the stove to your finger. Alternately, when you hold a cold can of beer or soda, heat is conducted from your hand to your drink. When Cally is blasted out of the airlock and floating in free space, she’s hardly touching anything; space is close to being a perfect vacuum. Her 3,000 square inches of skin would touch at best around 50,000 atoms in space—about the equivalent of a large protein molecule. If there’s little or no medium surrounding your body, there’s very little conduction to carry away your heat.

  That leaves radiation. When Cally and the Chief are in space, they will lose heat as it is radiated away from their bodies. This is a much slower process than conduction, and is certainly not instantaneous. The Tyrols certainly would not freeze in the few seconds they were exposed to the space environment. If Tyrol and Cally were left in space, their bodies would freeze eventually, but long after they perished by asphyxiation (as eventually happened to Cally, poor thing).

  In the movies Total Recall and Outland, we see a less-than-accurate depiction of the physiological effects of human exposure to a low-pressure environment. At the climax of the first movie, Quaid (Arnold Schwarzenegger) and Melina (Rachel Ticotin) are cast onto the surface of Mars without spacesuits. Their eyes bulge out of their heads, ostensibly from the pressure difference between that in their tissues and that of the rarefied Martian atmosphere. Even more dramatically, in Outland the viewer is treated to several instances where people, subject to a near-vacuum on Jupiter’s moon Io, literally explode from the pressure gradient.

  This simply would not happen either.

  Let’s say you were blown out into space, and let’s assume you did not hold your breath. What would the air in your system do? Would it burst your bodily tissues and/ or chest cavity, as in Outland? Or take the path of least resistance and flow out of your mouth?

  The air in your body would mostly take the path of least resistance and burst out of your mouth. Your eyes, your intestines, your bloodstream, and the rest of your body would slowly outgas whatever air remained behind in your tissues. If you were blown into space—like Cally and Tyrol—the majority of the air in your body would simply flow from your lungs, out of your nose and mouth. As it passed from your body, cooling from the gas’s sudden expansion might cause the moisture in your breath to freeze, and frost might form around your nose or lips. A small amount of air would take the more difficult route, and might burst small blood vessels in your nose and/or eyes, as well as a small fraction of the alveoli in your lungs. Nitrogen would bubble in your bloodstream. Your eardrums might very well rupture, but you wouldn’t.

  If, somehow, you managed to survive the experience, you’d have a major league case of decompression sickness, more commonly known as “the bends.” The nitrogen dissolved in your blood as a normal function of respiration creates bubbles in the blood when your external confining pressure is reduced rapidly. This can cause incredible joint pain. Severe cases of the bends can lead to paralysis, even death.

  A patient suffering from decompression sickness can be treated by placing them in a recompression or hyperbaric chamber. By overpressurizing the atmosphere around the victim, then depressurizing slowly, effects of the bends can be mitigated. This is exactly what happened for Cally, and in the same scene where Cally was relegated to a hyperbaric chamber, we also see that blood vessels in her eye did, indeed, rupture. One can infer that Cally had a worse case of the bends than did the Chief. Then, again, the Chief is a Cylon; who knows how resilient they really are?

  In short, exposure to the near-vacuum of space would leave you very uncomfortable and unhappy, but if you were rescued quickly enough, you could easily survive it. ‹

  CHAPTER 14

  The Effects of Nuclear Weapons, or How the Cylons Can Reoccupy Caprica after a Few Days but Not Dead Earth after Two Thousand Years

  Throughout most of the first-season episodes, we see Cylons living in the abandoned cities of a postnuclear Caprica. Then, in the fourth season, we learn that Dead Earth (nuked more than twenty centuries earlier) cannot be inhabited. Is such a thing possible? Can a planet like Caprica be nuked and then become almost immediately inhabited by radiation-sensitive people, while another, similar nuked planet remains a wasteland?

  To understand this, we need to look at some of the effects of nuclear weapons. Giulio Douhet was an Italian general in World War I who practically invented the theory of strategic bombing from the air. In his 1921 book The Command of the Air, Douhet said that the perfect device for aerial bombardment of cities would consist of a mixture of high explosives to destroy buildings and create kindling; incendiary bombs to ignite that kindling and create a conflagration that would sweep across the area—a firestorm; and some form of long-term poison gas to prevent firefighting, rescue, and cleanup forces from moving into the area.

  Caprica being nuked.

  Nuclear weapons essentially are General Douhet’s perfect bomb. In a
typical nuclear weapon detonated in the lower atmosphere, approximately 50 percent of the total energy of the bomb is spent as blast—Douhet’s high explosive. Approximately 35 percent of the energy of a nuclear weapon is spent as heat or thermal radiation—Douhet’s incendiaries. Approximately 15 percent of the energy of a nuclear weapon is spent as ionizing radiation and residual radiation—Douhet’s long-term poison.

  Let’s look at blast damage first. Where Douhet imagined hundreds or thousands of medium-size conventional bombs raining down on a city, a single nuclear weapon can knock down buildings across an entire metropolitan area. In a “typical” strategic nuclear detonation, the blast usually happens in the air over a target, and is optimized to create maximum overpressure on the city itself, anywhere between 5 and 15 excess pounds of pressure per square inch. To create this overpressure, a 10-megaton nuclear weapon can be detonated at as high as 10 kilometers (6 miles) over a city (smaller nuclear weapons will, of course, be detonated at lower altitudes). In the miniseries, we see the Cylon attack begin with a silent nuclear detonation in the sky, visible from Baltar’s house. Later attacks are also clearly airbursts: one gives a newscaster in the studio a brief moment to react to the flash before she is killed by the blast. That same blast traveling outward in a spherical shock wave at about 1,000 kilometers (600 miles) per hour, near the speed of sound, also wipes out a reporter in the field about 1.3 kilometers (1 mile) away from the detonation. Much of the devastation of a nuclear weapon is caused by blast, since most buildings are not built to handle the overpressure brought by the shock wave (witness how Baltar’s house disintegrates around him).

  Admiral William Adama.

  William and Lee Adama.

  A few seconds after the blast wave hits a given location, air comes rushing back in to fill the “vacuum,” thereby creating a second, smaller pressure wave from the opposite direction. Both waves do a great deal of damage to structures and people.

  About 35 percent of the energy of a nuclear bomb is released as visible, infrared, and ultraviolet light. Any object in a direct line of sight to the explosion will receive some of this light. Depending on the color and composition of an object, this light will be reflected, transmitted, or absorbed. For a one-megaton bomb, anything in a direct line of sight up to approximately 1 kilometer (0.6 miles) from ground zero will catch fire and burn. Many such fires, started in the blasted remains of buildings, will almost surely evolve into a firestorm.

  A firestorm is a fire that is so intense, and burns for so long, that it creates its own wind system. Firestorms are not unique to nuclear weapons; they also occur in forest fires, and were a major consequence of the Allied conventional bombings of the German cities of Dresden and Hamburg in World War II. In a firestorm, a large conflagration on the ground creates a column of superheated air that can rise into the stratosphere. The rising air pulls in low-level air behind it, bringing in fresh oxygen to feed the fire; in a large enough firestorm, the winds can reach hurricane force. As fresh oxygen feeds the flames, the fire burns hotter, and the winds become more erratic. This can sometimes create small cyclones of fire outside the burn zone, allowing the fire to spread. A firestorm ends when weather conditions change, or when firefighters manage to control the periphery of the fire, or when there is nothing left to burn. A firestorm in a nuked city has the potential to destroy more buildings than the original blast. The “Lest We Forget” photograph, which Galactica’s pilots touch for luck on the way out of the ready room, almost certainly shows a Colonial soldier witnessing a firestorm on Aerilon.

  A worldwide nuclear war, with resulting firestorms across the planet, brings another danger—the real possibility of “nuclear winter.”

  When the particles of soot from a firestorm make it all the way to the stratosphere, they can remain suspended in the atmosphere for many years and block a significant portion of sunlight from reaching the surface. This can have the effect of cooling the surface of the planet, so much that temperatures in post-attack summer might be colder than pre-attack winter. In such a scenario, crops will not grow, and billions of people not directly affected by nuclear blasts will suffer as the world’s food runs out.

  Yet despite firestorms and nuclear winter, probably the scariest effect of nuclear weapons is radioactivity, which accounts for about 15 percent of the total energy of the bomb. Radioactivity, as we saw in chapter 13, “The Wonderful World of Radiation,” is an effect of the breakdown of an unstable atomic nucleus, causing the nucleus to give off particles and waves, which could take the form of helium nuclei (a.k.a. alpha particles), electrons, or high-energy photons.

  Curiously, the initial burst of radioactivity associated with a nuclear detonation is probably the last thing you have to worry about during a large-scale nuclear attack. If you’re close enough to be harmed by the initial radiation, you’re probably close enough to be killed by the blast or thermal pulse anyway.

  But then there’s fallout.

  Fallout is bad. Unbelievably bad.

  Fallout is made of vaporized soil, vaporized buildings, vaporized people, and vaporized nuclear material from the bomb itself, created in the first seconds of a nuclear blast. These generally condense into microscopic radioactive particles in the explosion’s mushroom cloud. Some of these radioactive particles fall back to the ground close to the explosion. Some are carried by winds, bringing their radioactivity dozens or hundreds of miles from the site of the explosion. Others make it all the way up to the stratosphere, where they spread around the world before bringing their radioactivity back to the ground.

  The human race could be expected to survive an all-out nuclear war if the sole effect of atomic weapons were blast. We might survive the resulting nuclear winter if the only effect of atomic weapons was blast and fire. It is entirely possible, though, to design nuclear weapons in such a way as to maximize the intensity and duration of their radioactive fallout—blanketing Earth with intense radiation that lasts for years, destroying not only humanity, but nearly every living creature on the land and sea.

  This is probably the difference between nuked Caprica and Dead Earth: the fallout. The mechanical creatures who blew up Galen Tyrol at the farmers’ market on pre-Dead Earth could easily have “salted” their nuclear weapons with a few kilograms of any of the following parent isotopes.

  Parent Isotope1 Radioactive Product Half-Life

  Lithium Fluoride Fluorine-18 109 minutes

  Magnesium-24 Sodium-24 15 hours

  Gold-197 Gold-198 2.697 days

  Tantalum-181 Tantalum-182 115 days

  Zinc-64 Zinc-65 244 days

  Cobalt-59 Cobalt-60 5.26 years

  The parent isotopes are nonradioactive, relatively abundant, and easy to obtain. A nuclear explosion will convert these parent isotopes to a specific radioactive isotope, and that’s where the killing lies.

  The radioactive half-life is the expected time it takes a radioactive substance to decay to half its initial strength. Suppose we have a quantity of radioactive cobalt-60 that is undergoing an average of 1,000,000,000 radioactive decays per second. A little more than five and a quarter years later, that same quantity of cobalt-60 will be experiencing only 500,000,000 decays per second. Five and a quarter years later (10.52 years after we started measuring), it will have an average of 250,000,000 decays per second, and so on. Since cobalt-60 radiates particularly energetic gamma rays, any area contaminated with the isotope is going to remain uninhabitable for a long time beyond the five-year half-life. By carefully exploding an awful lot of cobalt bombs in ways that will simultaneously maximize the amount of fallout and put that fallout into a planet’s stratosphere, the mechanical creatures that destroyed the 13th tribe could, in theory, create a “doomsday shroud” of radioactive particles that would completely blanket Dead Earth and destroy all humanoid and animal life.bh

  Isotope salting works with “standard” nuclear weapons. But it is entirely possible to redesign nuclear weapons in ways that will modify their innate radiation effects. When
we see the Cylons walking around undamaged portions of Caprica City soon after the attack, it leads to the assumption that—at least in certain areas of their attack on the Twelve Colonies—the Cylons used neutron bombs.

  Neutron bombs, known in Pentagon-speak as “enhanced radiation weapons,” were thought up by Sam Cohen, a researcher at the Lawrence Livermore Laboratories. During the Korean War, he had seen first-hand the destruction that war brings to civilian populations. He knew that there was talk in Washington of possibly using atomic weapons in Korea, and Cohen realized that if conventional war treated civilians so badly, nuclear war—which can be targeted almost exclusively at civilians—would be even worse. There had to be a way to use nuclear weapons in a way that would benefit, or at least not hurt, civilians.

  Cohen used his nuclear physics background to develop the idea of a neutron bomb: a nuclear explosive specifically built so that most of the energy comes out as radiation—not blast or heat—and most of the radiation comes out as neutrons. A small neutron bomb exploded three thousand feet in the air will do minimal damage to buildings, but will put out enough radiation to kill nearly every person in a half-mile radius. Being neutral particles, neutrons have a strange effect on the human body: above a certain limit, you will certainly die relatively quickly; below that limit, you will certainly live, with very few side effects. Also, neutrons do not produce fallout or lingering radiation to contaminate an area—an area blasted by a neutron bomb can be reinhabited a few minutes after the explosion (or after the bodies have been carted away). Cohen calls neutron bombs the most moral weapons ever made.