By slamming into the planet at many times the speed of sound, triggering tidal waves, setting off earthquakes, vaporising anything in the impact radius, and causing centuries long dust storms, I hear you say.

Well, yeah.

But I’m not asking the question in the physical repercussions sense. I’m asking the question in the the sense of how asteroids in relatively stable, near-circular orbits out in the main belt between Mars and Jupiter, can be dislodged and get into the inner system where they could cause, in Busta Rymes infamous phrase, “Extiction Level Events”.

If we can understand that, then maybe we can save ourselves having to send Bruce Willis out to save the planet.

One method is obviously via collisions between asteroids within the belt, or collisions between asteroids and passing objects such as comets. Given the vast number of objects that make up the main belt, and the gravitational fluctuations that arise due to the relative positions of the Sun and Jupiter, I would anticipate that these kinds of collisions are not uncommon.

However, these types of interactions are by their nature fairly chaotic and unpredictable. This is why the skies are constantly being scanned by teams of astronomers dedicated to looking out for rogue asteroids. An unexpected collision could set a asteroid on a trajectory that would impact with Earth in a matter of years. Sounds a long time, but given the high cost and technical difficulty of easing one of these asteroids onto an alternative path, we might need every last day of warning to avert catastrophe.

Are there any other more predictable means by which asteroids might be subjected to forces that move them into dangerous inner system elliptical orbits?

Yes.

Strangely enough, the combination of the fact that most asteroids are spinning to a greater or lesser extent, and that they’re bathing in a constant stream of solar radiation, means that all asteroids feel a steady radiation thrust in a direction perpendicular to the inward gravitational force. The effect comes about because solar radiation takes time to be absorbed and re-emitted by the surface of the asteroid. In this time, given the rotation of the asteroid and the differential temperatures between the sun-side and the dark-side, more heat radiation is emitted on one side than the other, corresponding to a small thrust. The effect is named after its discoverer Ivan Yarkovsky.

Of course the effect is tiny, but over the course of millions of years this process can steadily alter the orbit of an asteroid. In this way, the main belt can act as a steady reservoir for missiles that can be flung at the inner planets causing craters like the one found at Meteor Crater near Flagstaff, Arizona, or the tree-flattening devastation of the Tunguska Event in Siberia.

Maybe it was my age, maybe it was the captivating performances, maybe it was the spine-tingling terror that the original film induced, but when I watched Alien sometime in the early Nineties (after hearing about from some kid at school who kept impersonating the grunts in the second film, Aliens), I came away breathless with awe. And I don’t remember having too much of a problem with the science either.

Skip forward twenty years, and oh-boy, do I wish I could hold the latest chapter–or prequel–in the Alien franchise, Prometheus, with the same reverence. Not only did I come away thinking that the film failed artistically, emotionally, and most of all, logically, it also must qualify as one of the most excreable examples of Hollywood attempting something the media-execs probably go round calling “Scienze”.

Interesting Scientific American speak with co-screenwriter Jon Spaights about the roots of the film’s mythology, and yet don’t pull him up on any one of the egregious scientific howlers. Guess it’s down to Creepy Treehouse. Spoilers ahoy.

1. Gravity

Okay, we’ll begin gently. It’s almost a standard trope that starships will always employ some form of artificial-gravity, but it still pains the rigorous scientist in me when I see the crew of these vessels prancing around as if they were standing on good ol’ Earth. In Prometheus, the rough riding over this universal law is particularly in-yer-face as the AI caretaker character waltzes around playing basketball while riding a bike. Solution? One-gee acceleration out, one-gee deceleration after halfway. Centripetal force. Take your pick. Then you come up with the problem how humanity gets anywhere by the year 2093. FTL anyone?

2. Evolution by natural selection

In possibly the dumbest single moment in the entire film (although maybe not–there’s a lot of them), the “Redshirt” biologist challenges the Scientific Lead when she claims that maybe humanity didn’t evolve on Earth but was put there some tens of thousands of years ago by a “progenitor” species. “You mean, you want us to throw away three hundred years of Darwinism?” he asks. “Yes,” she replies. Argument won.

Woah! Hold your horses. I know this one’s probably for the Creationists, but Darwin’s theory isn’t a theory to explain the last few hundred years of life on Earth. Evolution by natural selection explains the last four billion years of life on Earth. The evidence is deep, diverse, and overwhelming. Humans are genetically related to the most primitive lifeforms that evolved aeons ago. So, either our “progenitor” species seeded life at the dawn of time on Earth and remained essentially the same for the interim period, or they added the homo sapiens species to an existing biosphere, just happening to match the existing DNA. Hmm.

3. Caesarean section

Dr Shaw, after becoming implanted with one of the “stomach rippers” takes the surgical procedures into her own hands when she uses the automated medical facility to extract the critter from her womb.  This involves cutting open a ten-inch long gash across her stomah, and using clamps to physically pull the invader out. Afterwards, within minutes, she is running around.

I don’t think so. Her stomach muscles are completely severed, her core strength knocked for six. She’d have trouble getting to the bathroom, never mind outrunning a crashing alien spaceship.

4. Biomass

The critter that she does pull from her stomach doesn’t die, of course. Despite being exposed to the automated facility’s “decontamination” procedures. Okay, I’ll buy that. What I won’t buy is the same organism then going on to become a giant octopus of writhing, carniverous tentacles with serious kissing-with-tongues issues that is bigger than the hulking white supermensch–when it has nothing else to eat. Conservation of mass. Come on, that’s basic!

5. Linguistics

In one scene, David, the mission’s AI awakens one of the Engineers, and in perfect Engineer language, doesn’t ask the obvious question–where do you guys relax?–but instead quizes the three-metre giant if Biff, sorry Peter Weyland, can suck on some special immortality juice before he kicks the bucket. Unless David has already had contact with the Engineer language–and I grant being an AI might give him learning advantages so as not to need as much time as us meat-sacks–there is no way he could’ve learnt the verbal language from a bunch of cuneiforms. (Why an advanced space-faring civilization would still be writing in triangles on stone like they were still at Playschool is another mystery).

6. Biological contamination

In one memorable and horrific scene, Meridith Vickers, the cold-hearted Weyland Industries representative, makes a stand on their vessel’s Entry Deck after an expedition to the alien pyramid goes wrong, and the group tries to bring back a clearly sick Dr Holloway. Despite half the crew breathing in the exoplanet air and opening themselves up to airborn infection on the first day, the dissection of an alien head with no quarantine procedures, and the obvious fact that Dr Holloway was probably infectious earlier in the day WHEN aboard the ship, Vickers torches him anyway.

And there’s lots more, but maybe someone else would like to point out what’s wrong with electrical stimulation of a two-thousand year old head, dating an archaeological site in the blink of an eye, professional scientists who dismiss evidence and instead “choose to believe”.

Damon Lindelof, the other co-writer recently said: “In really, really good science fiction the line between the science and the fiction is blurry.” I’m surprised Mr Lindelof is even able to make such a statement given the obvious paucity of his scientific knowledge.

For a discussion on the gaping plot holes, sorry, plot abysses (you just can’t get round these problems), see this post. And for a mainstream film that gets the science right go see Contagion.

I recently watched the excellent, Contagion, a film by Steven Soderbergh, which gives a harrowing, scientifically realistic depiction of the outbreak of a highly contagious, often fatal disease. Highlighting both the potentially rapid spread of virus outbreaks and the influence of social media scaremongers/conspiracists in today’s interconnected world, the film is a great advert for why we need our politics informed by scientists’ thinking more than ever.

One thing that the film really helps dramatize is the reason why epidemiologists are so keen to identify “Patient Zero” after the outbreak of an infectious disease. As you might have guessed, Patient Zero–or the index case as it’s clinincally known–refers to the first person who shows documented symptoms of the disease. In Contagion, that unlucky person is Gwynth Paltrow, who comes back to the US after a business meeting in Hong Kong, stopping off for a spot of extra-marital play during her layover in Chicago.

So, why do the infectious disease experts trip over themselves to find Patient Zero? Why don’t they just deal with the cases at hand? Two main reasons. One, the earlier in the outbreak of a disease that the scientists can identify the first human carrier, the better their chances of controlling and dampening the outbreak. By determining exactly where Patient Zero travelled and who they came into contact with, epidemiologists are often able to track the spread of an infectious disease, and undertake procedures to isolate and treat the people who might be carriers. If this is done early enough, before the disease has spread to too many individuals or to “supercarriers”–human vectors who, by virtue of their profession or disposition are likely to infect many others–the outbreak can be artificially “shutdown” before it runs its natural devastating course. It really is a race against time.

While the first reason concerns the onward trajectory of the disease, the second looks back to its origin. By identifying Patient Zero, epidemiologists have a strong chance of locating the exact place where the first infection happened. Often harmful viruses exist in some natural “reservoir” such as a population of wild animals like bats or civet cats, and somehow this virus ends up coming into contact with Patient Zero. Learning about the environment in which Patient Zero fell sick can often lead to the identification of the source of the virus, which allows preventative steps to be taken to stop future epidemics. In Contagion the scientists eventually discover that “The wrong bat met the wrong pig”, leading to poor Gwynth’s infection when a chef shakes her hands after handling contaminated pork.

In a future post I’ll look at the basic mathematical models that epidemiologists use to predict disease outbreaks, and why vaccinating the entire population isn’t necessary!

Red Dead Redemption, GTA IV, Limbo. Works of creative genius by some of the most imaginative, most talented video game designers on the entire planet. All made by humans, of course. One PhD student at Imperial College, London, however, is on a mission to show that in the future some of our video games might be made, not be people, but by computers.

Step forward ANGELINA, one of the early AI pioneers of this new realm.

Now, before we get too excited, ANGELINA isn’t a true sentient AI encased in a metallocerramic carapace who goes out into the real world and gets inspired by Mozart symphonies, glorious sunsets, and the street art made by vomiting drunks, then goes back to her robotic garret and codes a masterpiece. Oh no. ANGELINA is merely a computer program who knows very little, if anything, about her digital creations.

So, how can she create games?

Answer: by leveraging the powerful force that is evolutionary computing. Let’s unpack that a little. First, what is evolution? Well, in the natural world, evolution is the chemico-biological process by which species evolve and diversify. Anything that produces offspring is in thrall to the power of evolution. This happens because when a biological entity reproduces, either sexually or asexually, the offspring are usually slightly different from their parents. Those which have developed traits that make them better at surviving their environment will be more likely to produce more offspring themselves, thus propagating their succesful traits. Those whose traits are a hinderance rather than a help will be less likely to reproduce and the trait will not be passed on.

On a human timescale we don’t see the effects of evolution in most organisms because it takes many generations for these traits to propagate. However, by mimicking evolution inside a digital space where we can speed up the process by many orders of magnitude, we can evolve, not just digital organisms, but anything that can be represented by a “genetic” code and tested in whatever way we see fit: aircraft fan blades, Prisoner’s Dilemma strategies, and, you guessed it, even video games!

While in nature the “fitness function” is encapsulated in an organisms ability to survive and reproduce before dying, the fitness function for population members like fan blades and video games is less clear, and is one of the more difficult parts of creating an evolutionary algorithm. For example, what makes any given fan blade “good”–and therefore a stronger candidate for reproduction where its design can be finessed–will be a subjective blend of how much material is used, the length of the blade, its aesthetic value, perhaps, how much turbulence it generates etc etc.

In a domain such as video games this assessment might be even harder; one person’s Call of Duty: Modern Warfare 2 nirvana might be another’s Shaq Fu horror.

ANGELINA creates games by breaking down a video game into constituent populations that can undergo this evolutionary process, with each game of every generation tested by a simulated human player that makes a numerial assessment of its “fitness”. For example, level-layout, enemy behaviour, and power-ups are each seperately evolved before being combined. The games that score highly will then have their constituent parts “reproduce” which will result in a new generation of slightly different levels etc, some worse than before some better. Those that are better will form the basis of the next generation, and in this way ANGELINA optimizes her collection of games, eventually–hopefully!–producing something that a real person can play and enjoy.

Judging by ANGELINA’S creations I don’t think Peter Molyneux–creator of Powermonger, Syndicate, and Magic Carpet, among many other classics–has to worry, but maybe some of the Indie studios churning out dime-a-dozen game apps for Android and co. should!

Tesco’s motto might be Every Little Helps, but in an apocalypse Britain’s biggest supermarket will probably be offering nothing–unless you raid one of its depots early before the rest of the desperate get there. Then you might be able to snag a year’s supply of petfood or something.

But, pillaging aside, what can the appliance of science do for your eating habits when Armageddon falls?

First off, it should be noted that the cultivation, reaping, preservation, preparation, cooking, and all the other activities pertaining to the consumption of foodstuffs to keep you alive during whatever apocalyptic winter you have found yourself enduring, is a subject way more complex than can be described in one simple blog post. For this part of the survivors guide, further research into soil chemistries, migratory patterns, edible taxonomies, animal husbandry, hunting tactics, and a whole host of other topics should be explored at your leisure.

Having said that, a few short tips underpinned by some sound scientific knowledge should go a long way to holding you in good stead. For the non-wandering survivor, the development of strategies to ensure food is available all year round will be critical; nature’s bounty, unlike the local supermarket’s, varies through the seasons.

A plentiful garden will live and die on the fecundity of the soil, and if the local environment doesn’t satisfy in this regard, a good composting heap will be essential. In essence, a compost heap is a place where bacteria convert food waste into plant food, breaking down spent foods into the building blocks of future grub. For a small heap, non-vegan organic matter should be excluded to avoid any soil contamination. This means no fecal matter from non-herbivorous species, and no flesh or dairy of any animal. All other food scraps can go in.

A good mixture of carbon and nitrogen is the key to a succesful compost. Carbon can be found in dried lawn refuse–straw, sticks, and leaves, while nitrogen can be found in foodstuffs and freshly cut grasses. As all good high-school biology students know, bacteria break down organic matter best in damp, hot, and well-oxygenated conditions. A poorly ventilated compost will lead to anaerobic respiration and foul smelling gases like methane. Don’t suffocate your bacteria! For heat, solar reflectors made of abudant and otherwise useless materials like compact discs, are perfect. When the compost is rich brown and crumbly it is ready!

After growing bountiful crops while conditions are ripe, the second thing a seasoned survivor will do is ensure that she can preserve her harvest through the fallow months. Food preservation is built on the principle of preventing the growth of bacteria, yeasts, fungi, and other microorganisms, as well as slowing down the oxidation of fats that cause rancidity. A whole cornucopia of ingenious methods exist to these ends–many of which a clever survivor can leverage.

Dehydration causes the food to dry, thus inhibiting bacterial growth. Avoid direct sunlight to prevent the food getting too hot and not drying fully. Refrigeration slows down the growth and reproduction of microorganisms, and slows the action of enzymes. A buried fridge or a watertight container immersed in a cold, running stream, will work for those not considering a mechanical refrigerator such as a reverse-run Stirling engine. Vacuum packing will deprive bacteria of oxygen. Curing–or salting–food draws moisture from meats through the process of osmosis (as outlined last week!). Smoking foods over a badly-oxygenated fire will aid preservation as the smoke acts as an antioxidant. Pickling in an edible anti-microbial fluid such as brine, vinegar, alcohol, or vegetable oil, will kill or inhibit bacteria–and get you sloshed if you have some good liquor! For those with access to radioactive sources, irradiation will kill bacteria, molds, and insect pests, but not viruses. To be honest, if you had your own gamma ray source I might be suspicious about your role in the apocalypse in the first place . . .

As to hunting, for the cowardly survivor who doesn’t want to take on the more dangerous beasts, a small dab of honey will usually lead to a profusion of ants that can be fried up nicely for a good dose of protein!

Any more tips?

Like it or not, over the coming decades robots will play an increasing role in our lives. They will clean our homes, mix our cocktails, even drive our cars. They may even become street entertainers, amazing us with their catching skills!

What has any of this got to do with the humble quadratic equation? The seemingly innocuous polynomial with the complicated “solution” that’s found in the front pages of exam papers, and is the bane of many high school mathematics students’ lives.

Read on to find out.

Imagine. You’re a fielder on a rounders’ pitch, standing out in the deep, the glare of the sun making your eyes squint. The opposite team’s big hitter has just come out, and is swinging her bat like she means business. Your pitcher tosses a lame throw, and — WHACK — the ball is struck far and high, and worst of all is arrowing in on your corner of the field.

No drama, though. You’re good. Somehow, by the magic of that wondrous computing device, your brain, in conjunction with your eagle eyes, you know where the ball is going to land. You get there. The ball comes down, hard and fast. You raise your hands, and–

OUT!

You might not be consciously aware of it, but the fact of the matter is that you’ve just solved the numerical/computational equivalent of a quadratic equation. How so? Well, the trajectories of objects under the sole influence of gravity are actually described by parabolas–the curves you get when you plot a quadratic equation. What this means is that if you can take a “measurement” of the ball’s position and velocity i.e. its speed and direction at any moment, then its future position at any later time in its flight is completely determined. Basically, you know pretty accurately where it’s going to land the moment it’s hit. And you can update your estimate on the fly, getting a more and more accurate prediction the longer the ball is into its flight.

Whether our brains actually “solve” a quadratic equation or use a numerical methods that lead to similar predictions is up for debate–the brain with its massively parallel and interconnected neuronal structure is unlike the simple algorithmic computing devices we build–but what’s certain is that the programmers and engineers who create juggling robots are getting their creations to solve quadratic equations in order to catch the balls.

So, next time you’re staring at a ax² + bx + c = 0 and wondering what possible use solving this equation could bring, think about the next generation of robots whose very foundations might’ve been laid in the intimate knowledge of this piece of mathematica. From auto-laser weapon systems disintegrating enemy mortar shells, to car manufacturing plants where components are lobbed between the robotic construction workers, the quadratic equation could be key!

Tiger Woods look out, your golfing nemesis is coming.

Last week I attended one of Café Scientifique’s series of public forums at the Royal Society in London, in which Dr Zita Martins, a University Research Fellow at Imperial College, London, gave a short talk entitled “What’s left to explore in the solar system?” Her talk and extended Q & A session actually focused on her analysis of meteorites–rocks of non-terrestrial origin that reach the surface of the Earth–and covered a wide-range of fascinating subjects.

Meteorites, as opposed to meteors that disintegrate in the atmosphere, give us a unique glimpse into the material universe away from our planet, and have important things to tell us about asteroids, solar system formation, and possibly even the origin of life. During the Q & A session I asked Dr Martins how we could be sure that the organic material found within a special class of metorites called carbonaceous chondrites were of extraterrestrial origin.

Before I relay what she told me, I’m going to answer another question first: how can we tell if a rock is a meteorite which has undergone a spectacular multi-million mile journey through the depths of space, surviving the fireball entry through Earth’s scorching atmosphere, or is, well, a darn boring rock?

Well, first off, it’s not if a burning fireball ploughs through your roof and sets alight your home. That probably just means it’s November Fifth. Check your calendar. Unlike the Hollywood depiction of meteorites being red-hot lances of fire, meteorites are actually fairly cold when they reach the ground. The high-temperatures that burn up the smaller pieces occur at altitudes over seven miles, and by the time the meteorite hits the ground its travelling at terminal velocity–much like an ordinary stone thrown up into the air.

However, the friction and superheating of the compressed air in front of the meteorite, will lead to a effect called fusion crust over the rock’s surface. A thin black rind, approx. the thickness of apple skin, sometimes shiny, sometimes matte black, is good evidence of this phenomena.

Second, most meteorites are attracted to magnets due to their high iron content–which also leads to their third distinctive property–they are noticeably heavier than most terrestrial rocks. Fourth, they never have vesicles–small holes throughout the structure–which are common in volcanic rocks due to escaping gas when lava cools. Five, six, and seven are the “thumbprints” caused by the surface melting while travelling through the atmosphere, the metallic flakes and grain-like chrondules of the interior, and acquistion of a yellow/ochre patina caused by oxidation on Earth’s surface.

As you can see, identifying a meteorite is a complex task, and if a strange rock turns up in your yard chances are it’s been kicked up by a passing truck’s drive belt rather than hurled from the asteroid belt.

So, now we’ve confirmed we’ve got a genuine rock from the big dark deep on our hands, how can we tell that any organic matter it carries actually came with it?

Dr Martins informed me there were three major ways scientists could tell if the carbon compounds, including amino acids, seemingly present in the meteorite samples came from outer space. First, the organics in meteorites exhibit racemic chirality. They do what? Chirality is a property of objects that lack an internal plane of symmetry–like hands. Your left hand and your right hand are mirror images of one another, and even though they can perform the same functions, they are not identical. Many carbon molecules exhibit a similar quality, and can be divided into left-hand and right-hand versions. For reasons that are still not fully understood, it turns out Earth-based organics like amino-acids and proteins predominately show one or other of the two forms, whereas extraterrestrial samples show equal mixtures of both forms, racemic in other words.

The second method involves determining the isotopic ratios of the carbon present in the organics. Many elements come in naturally occuring “flavours” or isotopes where the nucleus contains equal numbers of protons (and therefore electrons making them chemically near-identical) but differs in the number of neutrons present. Carbon-12 and carbon-14 are examples. Terrestrial and extraterrestrial samples will exhibit differing ratios of these isotopes and can therefore be used to determine whether an organic compound is truly of off-world origin.

Lastly–phew!–a comparison of the soil organics where the meteorite fell and the organic matter purported to be in the meteorite should show detectable differences, furthering the evidence the meteorite wasn’t contaminated on Earth.

A question to finish with: where do you think the best place to hunt for meteorites is?

(Clue: you’ll want to take your thermals . . .)

Okay, so now you’ve sorted out the cosy shelter where you’re going to hunker down and ride out the collapse of civilization, it’s probably time you took care of your number one physical need: clean drinking water.

The bad news is with nobody home at the district water plant and your local supermarket overrun with flesh-eating zombies, turning on the tap or glugging bottles of Evian isn’t going to be an option anymore.

So where can you get your aqua vitae?

First off, we all know we can’t drink salt water (remember Waterworld?), but why is that? The answer lies in the process of osmosis. This is the movement of water from a less concentrated solution to a more concentrated solution through a partially permeable membrane–such as a cell wall. Your cells have a fairly low salt content. If they are surrounded by fluid with a high salinity–like they would be if you drank salt water–then there will be a net movement of water molecules out of your cells in an attempt to balance these concentrations. Unfortunately, this means you will dehydrate and eventually die.

No glugging from the sea then. Where do we find fresh water? Three main places: surface water, rain water, and ground water. Out of these three sources, ground water is the most naturally clean due to being filtered through the very Earth, but wherever you find your water it will still be advisable to undertake a number of steps to remove all contaminants.

The elements that make the water unsafe come in two varieties: pathogens and impurities. A simple filtration through a cloth or shirt sleeve will remove some of the larger impurities of grit and dirt, but to get rid of all of them and the pathogens a number of other methods will be required. If creating a fire is not a problem, then boiling your water will ensure all pathogens are killed. Of course, if you’re surviving at altitude due to a nanoplague outbreak that kills all warm-blooded life below 10,000 feet, you’ll need to add extra cooking time due to the boiling temperature being lower. If fire’s not an option, leaving the water standing for several days will allow impurities to settle out and most pathogens to die. In hot climates a combination of solar radiation and heat will kill the bacteria. Simply seal the water in a glass bottle half-painted black and lie it in on its side on aluminium roofing in the sun for the day.

And, if you’re really stuck in Waterworld with no “dry land”, then you can always knock-up a solar distillator that will cleanse the water of salts, pathogens, and impurities in one fell swoop. In its simplest incarnation a tray of impure water sits sealed beneath an angled piece of glass. Exposure to the sun evaporates the water leaving free of salts and impurities, and killing the pathogens. The water then condenses on the surface above after which it runs down the inside of the glass by the action of gravity, collecting in a trough. Simples.

Kevin Costner might’ve had webbed feet and gills, but I didn’t rate his DIY skills as I never saw his solar still . . .

Now you’ve had a refreshing–and safe–draft of the best drink on the planet you’re probably getting hungry. Tune in next week for giving your apocalyptic dinner a scientific once over!

A Christian Science Monitor scientific-literacy quiz has recently been making its way around the blogosphere. Maybe you’ve taken it? I scored 44/50. Respectable, but not where I’d like to be considering my purported role of trying to raise scientific literacy.

However, on reflection I came to the conclusion that not only does this quiz–and quizes like it–fail to give a good assessment of scientific literacy, it also highlights one of the most pernicious myths mainstream culture sometimes has towards academic disciplines. Let me explain. Although the media would often have you believe otherwise, science, in its primary form, isn’t a simple collection of facts about the empirical universe. Science is, first and foremost, an enterprise for discovering the general principles that govern our world. Some of the most powerful of these principles can be very simply expressed, but lead to incredibly complex systems and behaviours.

One example of that is the law of universal gravitation that accounts for the large scale structure of the universe. Another is evolution via natural selection, that accounts for the staggering diversity of life. These principles may lead to scientific facts, but scientific-literacy is by no means bound up in knowledge of those facts. For example, knowing what the periodic table is demonstrates a far higher degree of scientific-literacy than rote-learning the exact atomic number of every element in the table.

And it gets worse. Consider question two from the Christian Science quiz:

2. The Austrian monk Gregor Mendel’s observations of what
organism formed the basis for the science of genetics?

Can you spot the problem with this question being in a quiz purported to test scientific literacy? That’s right! Questions about the history of science have nothing to do with scientific-literacy. The bottom line is scientific-literacy cannot be measured purely by multiple-choice questions.

A scientifically-literate population doesn’t always have access to all the facts of the situation, but more importantly, they often understand the processes needed to acquire those facts.

Well, according to the Mayan Calendar (allegedly–this is such a prevalent meme this year it’s hard to know the truth), December 2012 will herald the Apocalypse. What form this is going to come in isn’t exactly clear, but with some basic science under your belt you’re sure to increase your chances of survival!

Now, apocalypse survival is no walk in the park–although, you know, a walk in the park might be exactly the kind of thing you need to do from time to time in this situation–so I’ve decided to break down the focus into several distinct areas. Today we’re going to look at shelter.

First you’ve got the issue of where to locate your abode. You don’t want to make a hash of this choice, because you–and maybe your descendents!–could be there for a while. Civilization, including the concept of property rights (yah!) and the existence of estate agents (boo!) will probably take a while to re-establish.

Urban areas are best avoided on account of failed sewage systems and toxic chemicals contaminating the water table, limited access to allotment/grazing patches, and psychos bolting down in Superdrug. Out in the wilderness proper will lower the chances of Mad Max style encounters, but here you’ll have to worry about lack of DIY resources, medicines and healthcare expertise, and a hostile environment. On balance if things aren’t super competitive I think I’d head for fertile land with good fishing in a nearby river and not too far from a small town for a post-apocalyptic social life and the ear of the local Doc!

So, with the location sorted it’s now time to put some thought into your humble shelter itself. A clue is in the word itself. Shelter. Keeping out the nasty stuff. Keeping in the good stuff. Beyond the basics of a stable, waterproof home, a grasp of thermal physics will hold you in good stead in this regard. Not too hot in summer, and not too cold in winter. How can I do that without my aircon/central heating system/electric blanket I hear you asking? Without too much difficulty if there isn’t huge clouds of radioactive fallout blocking out the sun actually.

Passive solar heating is the name of the game. By making sure your shelter is effectively insulated, both Heat and Cold can be “trapped”. Tyres from all the abandoned vehicles, packed tight with dirt and gravel, then stacked and covered from the elements would make excellent insulating structure. For the Northern Hemisphere, in the winter double-paned glass windows set in south-facing windows will maximize the amount of solar energy coming into your cosy abode. After being absorbed in the wall, floors, and other objects at short IR and visible light frequencies, these things emit longer wavelength IR radiation that cannot pass through the glass. Hey presto you’re kept warm! And in the summer, by shading the windows the sun shouldn’t add too much extra heat (the sun is higher in the sky in the summer months too). In short, your House should be longer on the East-West axis than the North-South to maximize exposure to the sun.

Home-made radiators? No problem! Materials with high specific heat capacity–a barrel of water or earth would be perfect–can absorb solar energy in the sun through the day, then be brought inside at night where they can radiate this heat over the course of several hours. For cooling in the summer, wing walls–short vertical walls placed outside between adjacent windows–will force air currents to circulate and create a nice breeze!

So, now your home’s all sorted isn’t it time for a drink? Find out next week how to make sure that water is safe!