Science In My Fiction

Part I: a more traditional model.

Everybody loves dragons. And while wingless ones built along the lines of Komodo dragons or alligators can be a viable part of your fantasy ecosystem, let’s admit it. We want them up in the air and breathing fire or electricity or something fun.

A quick survey of existing flying creatures: the flying fox can get as large as 2.5 to 3 pounds and a wingspan of nearly four feet. The harpy eagle‘s wingspan can be 6 to 6.5 feet and they top out at 20 pounds or so.

Mind you, I would not want to meet a 20-pound dragon with a 6.5-foot wingspan, or be on the wrong side of its talons. And a hero would look really bad-ass when his pet swooped down to land on his (steel-reinforced) falconing glove.

In green, the Quetzalcoatlus northropi, with a human for comparison. Modified from a diagram featured in Witton and Naish (2008).

Let’s aim higher.

Quetzalcoatlus is the largest flying dinosaur discovered so far. Estimates vary, but it seems safe to assume a wingspan of 30 to 35 feet (9-10.5 m). Weight estimates have varied from as light as 150 to over a thousand pounds (68-453+ kg) (in a 2010 estimate generated mathematically). The first question is, of course, can this creature get into the air? Ostriches are the only current birds of similar weight — and they top out at 300 pounds.

Will it fly?

The issue was addressed by Witton and Habib in a 2010 paper on giant pterosaur flight dynamics. Their analysis of existing fossils and reconstructions of musculature led to some interesting possibilities. For their analysis, they settled on a Quetzalcoatlus of 32-36 foot (10-11 m) wingspan and 400-550 pound (180-250 kg) weight. Witton and Habib assert that these giant pterosaurs had sufficient bone strength and muscle for flying — with some mild caveats.

• Assisted launching. The pterosaurs may have launched themselves with a strong jump followed by vigorous flapping. You can find a wide variety of birds using this strategy, especially larger ones like eagles. Others have suggested that pterosaurs may have used the running-start approach to launch or jumped off cliffs to get that initial burst of speed. Witton and Habib lean toward the jumping method, though.

• Soaring. Rather than flapping constantly, pterosaurs may have done most of their flying by finding thermals and winds to soar on. Albatrosses and vultures do this a lot — it saves a great deal of energy, and when you’re big you need to save energy.

• Moving on land. Pterosaurs were not built for it. But the authors theorize that they may have been able to get about by hopping/jumping (saltation, as sparrows do) and possibly bipedal walking (many birds do this — ducks, robins, hawks…).

What does it eat?

Witton and Naish wrote a 2008 paper on morphology, in which they addressed some of the questions of the morphology and ecology of giant pterosaurs, including Quetzalcoatlus. It’s good reference material, but chances are you aren’t building a dragon with a stork-like beak and a neck that’s long like a stork but less flexible — like a lizard. They lay out some reasonable options for such creatures, but a traditional dragon with a shorter muzzle, teeth, and greater neck flexibility will have more predatory options.

Bearing in mind the three rules of predators as formulated by me (and only me): 1. Don’t get hurt. 2. Don’t work too hard. 3. If it gets you food, do it. Also bear in mind that while an earth-bound predator can gorge on a kill and then slink away to digest, a flying predator can’t eat so much at once that he can’t fly away if threatened. Many small meals throughout the day are probably the best strategy.

• Fishing. This is a perfectly good way to acquire a relatively large amount of calories with a reasonable amount of work. Given the general structure of a Quetzalcoatlus-based dragon, I would think that divebomb-style fishing (as done by ospreys and eagles) could work.

• Carrion. It’s not glamorous, but it fulfills rules 2 and 3.

• Traditional airborne hunting. This could be hunting birds, other dragons, or earth-bound prey, as falcons and hawks do. But bear in mind the stipulation about over-eating and the fact that it’s easier for a rabbit to hide in a forest than for a fish to hide in a lake. Hunting animals that congregate in large groups in meadows (or other open terrain) will make hunting easier… but also remember that we’re talking about a 30-foot wingspan dragon blotting out the sun. It’s difficult to miss that flying overhead, one would think. Or can you find a work-around for that?

Will it breathe fire?

Scientifically, the problem with breathing fire has always been the question why does it need to? Anne McCaffrey came up with one of the best answers (we bred them to do it) but in strict ecological terms, teeth and talons are quite sufficient for all your hunting needs. And if a feature isn’t useful to a creature’s survival, it isn’t done. Right?

Well, except for things that the opposite sex finds attractive. Such as peacock tails, silly dances, and the ability to compose sonnets.

Your mission, should you choose to accept it: imagine fire-breathing (or lightning bolts, what-have-you) as a mating display. We will get back to this in Part 2.

In December 2010, NASA announced a momentous discovery: bacteria that could use arsenic instead of phosphorus in its genetic material, a direct substitution in the DNA. This would be a huge deal if true, rewriting much of what we know about basic biology. People were hoping for alien life forms, but this would be nearly as important, if much less glitzy.

We already knew that bacteria could use arsenic in their metabolism; the ability to use it in their DNA would mean that they didn’t need phosphorus at all. The most abundant elements in living organisms are: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. All are believed to be essential for life. Substituting arsenic for phosphorus would alter that basic principle.

Scientists were immediately skeptical of the claims of Dr. Wolfe-Simon and her colleagues. Many insightful critiques were published online, but the authors of the original paper stated that they would only answer peer-reviewed rebuttals. Our own Dr. Athena Andreatis discussed the arsenic findings on her blog, and for Science in My Fiction.

Such a tremendous claim requires immaculate science and immaculate reporting, and neither were apparent.

In June 2011, the original paper finally saw print in Science (it had been available online since December). The reason for the delay: eight additional peer-reviewed technical comments on the original paper, and a response to those comments by the original authors.

I read all of them carefully with the intent of writing a summary to accompany my earlier essays about the arsenic bacteria, but never did. The short version of what I would have said: The eight comments pointed out several errors in methods and analysis. Some of the most major problems were described by several of the comments. I’m not the right kind of biologist to appreciate the nuances of molecular technique, but these descriptions of failings in the research were convincing.

Dr. Wolfe-Simon’s response boiled down to, “We did so do it right.” There wasn’t a substantive response to any of the problems raised.

The story isn’t over, but perhaps close. Dr. Rosie Redfield, one of the most outspoken critics of the original study and author of one of the Science comments, has tried to replicate the arsenic study with stricter methods and failed. Dr. Redfield and her colleagues found no arsenic in any of the bacterial DNA.

The original study appears to be a case of how not to do science. Based on interviews, Dr. Wolfe-Simon and her collaborators set out to demonstrate that this particular bacterium could substitute arsenic for phosphorus, and did not consider alternative scenarios or design methods that might clearly disprove their hypothesis. Their results were rushed into public without adequate peer review, but with much fanfare from NASA.

But since then, science has proceeded exactly as it should. Other scientists have raised issues in clear, technical fashion, and have tried to replicate these controversial results with more appropriate methods.

Although the key bits are or will be peer reviewed, much of the discussion has occurred openly on the internet, at least among the critics. None of the authors on the original paper have spoken up publicly, to the best of my knowledge, and have only responded to the comments that appeared in Science.

This has been a fascinating story to follow, but for the way the research was presented and followed up on than for the findings themselves. I try to end these articles with some consideration of story ideas. Here, I think the story comes from the people involved, rather than the science itself. (As, arguably, all the best science fiction does.) The discovery could have been anything, but the misinterpretation, critique and defense are what make it so interesting.

Edit (1 Feb. 2012): Dr. Redfield has now posted her mansucript on Arxiv for public comment. I have not read it yet, but wanted to let you know.

I find that there are few things that are more comforting than a tasty home-cooked meal. But cooking can take a fair amount of my time and energy, and requires that all the necessary ingredients on hand. Sometimes when I’m busy or tired or just feeling lazy, I wish there was a box of “people chow” in my cupboard that would make well-balanced and tasty meal, or perhaps a pill that could substitute for a satisfying dinner.

It’s not surprising that in the late 19th and early 20th century, when food preparation was much more labor intensive and time consuming than it is today, that writers who imagined scientifically advanced utopian societies of the future frequently described “instant” food that required no cooking.

The idea was common enough for writer Anna Bowman Dodd to satirize it in her 1887 novella The Republic of the Future, or, Socialism a reality:

The food is sent to us by electricity through the culinary conduits. Every thing is blown to us in a few minutes’ time, if it be necessary, if the food is to be eaten hot. If the food be cereals or condensed meats, it is sent by pneumatic express, done up in bottles or in pellets. All such food is carried about in one’s pocket. We take our food as we drink water, wherever we may happen to be, when it’s handy and when we need it.

Thus women were freed from the drudgery of the kitchen. Or as Dodd put it:

The perfecting of the woman movement was retarded for hundreds of years, as you know, doubtless, by the slavish desire of women to please their husbands by dressing and cooking to suit them. When the last pie was was made into the first pellet, woman’s true freedom began.

Dodd made it sound as if this would be a bad thing. But many thought that scientifically developed food substitutes would a positive development. At least in the first half of the 20th century, there were regular articles in the popular press about the “dream” of creating a meal in pill form.

And, of course, the pulp science fiction writers incorporated the idea into their stories.

By the way, have you folks eaten?”
“Not in a week,” said Karl.
“Von Sternberger’s food tablets,” informed the girl.
Carruthers nodded. His deep-set eyes regarded them appraisingly. “Any ill effects?”
“None whatever,” spoke Danzig. “Neither of us have the slightest craving for food.”
~ “Prisoners on the Electron” by Robert H. Leitfred (1930)

Sounds convenient, right? But here we are in the first part of the 21st century and most of us eat food that isn’t too far different from what people were eating a century ago.

So why don’t we have the equivalent of “Von Sternberger’s food tablets”? It turns out there are a number of reasons.

For one, we humans normally eat a wide variety of foods – a much wider variety than most other primates. A number of studies have shown that the diversity of foods we eat reflects the quality of our diet. Of course, that association is likely due at least in part to the link between poverty and a less diverse diet. Perhaps the lack of variety wouldn’t be a problem if scientists developed a food that met all human dietary requirements. It turns out not to be that simple.

We don’t actually yet know all the components that would make up an ideal human diet. For example, there are many compounds produced by plants – phytochemicals – that are thought to have anti-oxidant and other physiological properties. We are still learning what these compounds are and how they affect the human body, despite the bold claims of the dietary supplement sellers.

Another problem is humans have trouble eating the same food for every meal. Just imagine: there are 9 calories in one gram of fat, the most calorie-dense nutrient. That means you would need to eat a half pound of pure fat to get the 2000 calories burned daily by the average adult woman.  That’s a bare minimum, since balanced diets need to include less calorie-dense  components like proteins, carbohydrates and fiber.  While it’s not at all difficult to eat a pound (or more) of a tasty variety of foods per day, it’s harder to imagine happily swallowing a half pound of pills or eating a couple of pounds of not-particularly-tasty food pellets on a daily basis.

It’s not like people haven’t tried. A Canadian fellow named Adam Scott tried eating “monkey chow” for a week. At least in theory that diet should serve the nutritional requirements of most primates, including humans. The result? Scott lost weight, was tired and had serious cravings. While a diet of nutritious pellets might work as an alternative to Weight Watchers, it wouldn’t a very good replacement for human food. More seriously, even people who are malnourished have trouble eating enough food when the prescribed therapeutic diet is too monotonous.

And even if there is variety in our diet, food needs to taste good for humans to be healthy in both mind and body. For example, NASA has found that the “psychological well being” of astronauts depends at least in part on providing food that is tasty and has a “pleasant mouthfeel” . Because of that, NASA has moved away from the unappetizing food pastes and powders used to sustain astronauts on the Mercury missions, and worked on developing foods that the astronauts actually enjoy eating.

Naturally, science fiction has reflected many of those limitations.  In more recent SF stories, it’s more likely for mass-produced rations to be provided starving masses on resource-depleted and overpopulated Earth than to be eaten by the scientific or social elites.

All the TV shows have morale-builder commercials telling us how important our work is, how the whole world depends on us for food. It’s all true. They don’t have to keep reminding us. If we didn’t do what we do there would be hunger in Texas and kwashiorkor among the babies in Oregon. We all know that. We contribute five trillion calories a day to the world’s diet, half the protein ration for about a fifth of the global population. It all comes out of the yeasts and bacteria we grow off the Wyoming shale oil, along with parts of Utah and Colorado. The world needs that food.
~ Gateway by Frederik Pohl (1977)

Living on such food produced for basic sustenance, rather than for optimal health or pleasure, is a pretty bleak vision of the future.

Of course not all science fictional food is so unappetizing. In the resource-rich Star Trek universe, almost everyone can dine well on delicious synthetic food produced by replicators if they don’t want to cook for themselves.

Having access to a variety of food that tastes good, is nutritious and is available at the push of a button – that’s the future I’m hoping for.

Further reading:

• Paleo-Future’s “Meal in a pill” archives.

• Future Food section of David Szondy’s Tales of Future Past.

• NASA’s Space Food Fact Sheets and their Space Food and Nutrition site for students and educators.

• Cooper et al. “Developing the NASA Food System for Long-Duration Missions” J. Food Sci. 76(2):R40-R48 (2011) doi: 10.1111/j.1750-3841.2010.01982.x

Photo by epSos.de on Flickr

So, practically everyone knows thanks to Albert Einstein that on a starship traveling close to the speed of light time will pass more slowly than in the rest of the universe, though it does seem that not everyone understands how that works.  For example, I recall reading a passage in The Andalite Chronicles where the narrator explained that they were traveling to earth at a sub-light speed that would take them about three days because if they went at maximum burn they might make it in a few hours but that would be years on earth.  That’s just wrong, relativity slows down time onboard the ship, it doesn’t speed up time outside or anything.
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The crime rate may be down, but there are still plenty of villains to catch. Fortunately, science is on the case. That’s true in real life, where physicists devise more accurate ways to interpret blood spatter, and mathematicians analyze the patterns in gang violence to help solve old crimes and suppress future criminal activity. And it’s true on television, where forensic science has developed a vast and squeeing fandom.

Predictably, that fandom overlaps speculative fiction fandom quite a bit, but sadly, television science appears to have eclipsed science in sci-fi altogether. While it’s wonderful that scientists and Hollywood are forging new alliances for the sake of conjuring realism and as a canny method of reminding the masses that science is relevant to their interests, it’s disheartening to watch literature surrender that influence one sparkly vampire at a time.

No, it’s worse than disheartening. It’s uninteresting. And it’s unhealthy for speculative fiction to eschew – even disdain – science. Reading science-less sci-fi is like eating a junk food diet. How can the genre with science in its name be taken seriously if it’s about as intellectually nutritive as a Twinkie? Was it inevitable that television would eventually surpass literature as inspiration as well as entertainment?

Wonder of wonders, TV viewers like a little science in their fiction! Given the overlap between television audiences and people who read books, it’s probably safe to assume that readers also like a little science in their fiction. We should get back on that bandwagon.

Or to 2012, at least. Changing the numbers on the calendar often prompts me to think about calendars, and I’m not the only one. This year even more so than usual, what with all the Mayan calendar hype, and a proposed calendar reform in the news.

What’s wrong with what we’ve got, and why are calendars so complicated anyway?

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WE’RE ALL GOING TO DIE!!

You know, eventually. That’s the natural order of things. Most of us will survive 2012, though, in spite of everything the latest doomsday prophets claim. There are seven billion humans on Earth, after all. Writers, have you ever tried to kill off that many people in one story? It’s quite a lot of work, even in fiction, and much harder in real life. It’s not impossible, but according to the latest doomsday scientists, there’s no quantifiable indication that our end times are impending.

Let’s break it down for a little perspective:

• The end of the world? Earth itself won’t be destroyed until the sun expands in a few billion years. One way or another, we’ll all be long gone by then.
• The end of life on Earth? Including microscopic life, that’s also not due to occur for billions of years. Not worth losing sleep over.
• The end of life as we know it? Well, that happens every human generation, or so. Welcome change, really.
• The end of humanity? Psh! The extinction of a single species is hardly the end of the world. Remember the dodos, the Great Auk, and the dinosaurs?

Of all the different avenues along which people enjoy speculating about the apocalypse, most are at least tangentially political in nature. The nuclear holocaust is so overdone that it’s been rendered cliché. Pandemics are also in jeopardy of losing their social impact through overuse in media and other fiction. We’ll probably say the same about anthropogenic climate change in a few decades, even as we adapt to its environmental and economic ravages.

None of those political plot devices is likely to annihilate our species in 2012, but any of them is far more likely bring about our ignominious end than the equally tired religious mechanisms for the demise of human civilization. The second coming and the rapture? Ragnarok? The end of the Maya long count?

Actually, that last is the most absurd. You know what happens when we reach the end of the Maya long count? The same thing that happens when we reach the end of every other calendar invented since humans started measuring time in large units: We throw a big party, and we get a new calendar. Woo-hoo!

There are still a few arguably non-political tropes abused in doomsday prophesies. Polar shift, for example, which would certainly cause mass-extinctions if it was possible. However, in order to experience a polar shift in 2012, Earth would have to be on a collision course with an object so large that we’d be able to observe it with the naked eye by now. Our planet hasn’t had an experience like that since it acquired the moon a few billion years ago. Anyway, the term ‘polar shift’ is actually a red herring for a far more common event properly known as geomagnetic reversal. And that’s about as menacing as a slow-motion Y2K.

What about supervolcanoes? There’ve been an awful lot of earthquakes and eruptions lately, right? Eh, no. Earth is actually pretty quiet right now, on the scale of geologic time. Specifically, there is no indication that a supervolcano will erupt in our lifetimes, never mind in 2012. Specifically, there’s nothing about the Yellowstone caldera – the current favorite of geologic apocalypse-mongers – that suggests it’s going to do anything out of the ordinary any time soon. Even if it did, a supervolcanic eruption probably would not bring about human extinction, and it certainly couldn’t end the world.

Last and least, whenever anyone hears the term ‘Planet X,’ they should dissolve into peals of laughter on the spot. Really. In its proper context, Planet X is something out of a Daffy Duck cartoon, and that’s always worth a chuckle. Outside of its proper context, Planet X doesn’t exist. Anyone otherwise convinced is a fool easily parted from their money.

None of the catastrophes mentioned above are going to occur in 2012, but you can safely bet they and other variations on the apocalyptic theme will happen repeatedly in literature. Alas, not even that will end in 2012. The good news is that when it comes to making the most of flimsy premises and tired dread, fiction bests reality much of the time. After all, dystopia is practically its own genre, nowadays.

When I think about black holes in science fiction, I can’t help but think of that old Disney movie The Black Hole.  I was five years old (or maybe seven) when I saw it, so all I really remember is an uneasy glance passing between two astronauts as their space shuttle hurtles into a black hole.  At the time, this was scary – hey, I was five (or seven).  But it could have been so much scarier.

Since that movie came out in 1979, public perception of black holes has changed a bit.  The director of a Hollywood remake might be aware that astronauts can’t just fly calmly, or anxiously for that matter, into the very center of a black hole.  Strong gravity would pull an astronaut apart as they approach the singularity, starting with the nearest body part.  Let’s say an astronaut, we’ll call him Timmy, falls into a black hole feet first.  His feet will stretch toward the singularity.  His head will stretch too, but by a lesser amount.  He might even have a moment or two to examine the lengthening of his body before he is stretched into a thin strip of spaghetti and slurped into the singularity.  There is a technical term for Timmy’s experience: spaghettification.

Spaghettification

Spaghettification is a better explanation than what Disney came up with, but it doesn’t tell quite the whole story.  It’s true that once inside a black hole, Timmy would stretch tidally toward the singularity.  But as Timmy becomes taller and skinnier, the curvature of space itself changes.  The stretching quickly becomes so extreme, it produces its own gravitational field.  Turns out, gravity as Einstein thought of it is not the gravity we know and love.  Near something as extreme as a singularity, gravity becomes non-linear, meaning that gravity begets gravity.  So once Timmy starts stretching, all bets are off – as soon as he stretches one way, he induces an extreme curvature of space that reverses the stretch.  The oscillations will speed up as Timmy approaches the singularity, kneading him like dough one way then the other.  Theorists, not without a sense of humor, call this “Mixmaster dynamics,” named after the dough-kneading machine.  (By the way, in the simulation below, the blob stretches by a factor of 6.  Timmy, however, would stretch by a factor of 10^14.  For those not inclined to scientific notation, that’s a one followed by 14 zeroes…in other words, many times more than my measly brain can imagine.)

Gravity begets gravity, and so the bread-making begins.

Lucky for Timmy, the mixing doesn’t last long.  As soon as Timmy enters the singularity, he ceases to exist, his mass and energy converted to the energy of the black hole’s gravitational field.  At the singularity, matter no longer matters.  We might think of black holes as gaining mass as they swallow gas, stars, and little boys and their dogs, but really there is no mass at all, just a self-generating gravitational field.

Of course, the story for Timmy could end differently.  Einstein’s General Theory of Relativity describes gravity, but is limited to the world of Big Things.  Small Things, like atoms and electrons, are governed instead by quantum mechanics.  Singularities, being very small objects with extreme gravity, must be governed by both, but theorists have yet to understand how these two vastly different ideas might mesh together.  I bet Timmy can’t wait to find out.

And what rough beast, its hour come round at last,
Slouches towards Bethlehem to be born?

— William Butler Yeats, “Second Coming”

The last few years have been heady for planet hunters. First the hot Jupiters; then the will-o’-the-wisp Glieslings and their cousins; and in the last year, the results from the Kepler mission which detected planetary systems in the low thousands; one of these is Kepler 22.

Kepler 22 is a G5 type star (our sun is G2, about 10% bigger and hotter) 600 light years away with a planetary entourage. For anyone who was in a sequestered jury room or a silently running nuclear submarine, what got splashed across the news media on December 5 was the confirmation that one of the Keplerings is a super-Earth (2.4 times the radius of our planet) that is solidly within the habitable zone of its primary – habitable defined as the region where water can remain liquid. It circles its primary in 289 days and its estimated average temperature is a balmy 22 C/75 F if (big if) it has an atmosphere thick enough for a mild greenhouse effect.

That’s what we know, and it’s important and exciting enough. Here’s what we don’t know, which makes the exclamations of “Twin Earth!” annoying: we don’t know its mass (though the wobble velocity puts an upper limit of 36 Earth masses on it), its composition, the composition of its atmosphere or if it has any moons. Equally annoying are the suggestions to name it The Christmas Planet or the barely less mawkish Hope, right down there with the naming of putative Gliese 581g something like Betty (not even Elizabeth, which at least would celebrate an unforgettable historic figure, plus several literary ones).

The Kepler findings are pinning down the still-loose middle terms of the Drake equation by strongly indicating that most suns have planetary systems, and most planets are of the small rocky variety. Of the approximately 2,000 systems Kepler tentatively identified, about fifty have planets within the habitable zone, of which perhaps ten are “Earth-like” (loosely defined).

Half a percent may not sound like much. But given the quarter trillion suns in our galaxy, the numbers mount up quickly. Plus, of course, the size and location of the newcomer inevitably raises expectations: if Kepler 22b is rocky and has decent amounts of water and a reasonably thick atmosphere, the probability of life moves into the “likely” zone. So it’s not surprising that the Allen Array turned its dishes in the direction of Kepler 22 (no requests for Warren Zevon yet, but the night is still young) – or that the concept art is coming in thick and fast.

It is a great pity that Kepler 22b is so far. Even expeditions with quasi-exotic propulsion systems (or exceptionally nice humans in flawless arkships) would take a long time to reach it. But the lengthening list of not-quite-Earths is a powerful enticement not to abandon the faltering beacon of space exploration. Once again, I will close with what I said about Gliese 581g:

“Whether [Kepler 22b] is so hospitable that we could live there or so hostile that we could only visit it vicariously through robotic orbiters and rovers, if it harbors life — even bacterial life, often mistakenly labeled “simple” — the impact of such a discovery will exceed that of most other discoveries combined. Unless supremely advanced Kardashev III level aliens seeded the galaxy like the Hainish in Ursula Le Guin’s Ekumen, this life will be an independent genesis, enabling biologists to define which requirements for life are universal and which are parochial.

At this point, we cannot determine if [Kepler 22b] has an atmosphere, let alone life signatures. If it has non-technological life, without a doubt it will be so different that we may not recognize it. Nor is it a given, despite our fond dreaming in science fiction, that we will be able to communicate with it if it is sentient. In practical terms, a second life sample may exist much closer to home — on Mars, Europa, Titan or Enceladus. But those who are enthusiastic about this discovery articulate something beyond its potential seismic impact on biology and culture: the desire of humanity for companions among the sea of stars, a potent myth and an equally potent engine for exploration.”

Image: 1st, one of the four Kepler 22b imaginings by space artist Ron Miller. 2nd, comparison of Sol and Kepler 22 (NASA/Ames/JPL).

Postscript: Immediately after my discussion of Kepler 22b, Christopher Jones interviewed me for Trek.fm. He asked me many interesting questions about the 100-Year Starship symposium, long-generation starships and the future of humanity on- and off-earth. You can hear the interview here.

Everyone’s aware of the five senses of sight, smell, taste, touch and hearing, but did you know you have a sixth sense? And, although you can’t see dead people with it, this sixth sense does involve the subject of ghosts. No, this isn’t a over bloated movie review for M. Night Shyamalan and Bruce Willis, this is the fascinating world of proprioception.

Proprioception is a form of sensory perception that assists and enhances the other five senses and yet it is, in itself, a sense in its own right. Proprioception gives the body a sense of context, it manages spatial relationships, allowing you to close your eyes and touch your nose. If you miss, you’re probably drunk.

Proprioception is the sense that allows you to walk through a dark room without stumbling over your own feet. Teenagers, experiencing rapid growth, are clumsy not because they’re lazy and inattentive (as some of us dad’s may assume), but rather because their sense of proprioception is lagging behind their physical growth. They need to mentally grow into their new limbs. In the same way, someone that has had a limb amputated will often feel a “ghost” limb. They may feel a sense of twitching or even a desire to itch a limb that no longer exists.

Based on these examples, you may think that proprioception is simply an extension of touch, but it influences all the other senses. Coming from New Zealand, my family would often visit Rotorua during the holidays. Rotorua is a land of geysers and thermal springs. When driving into the city, you’re invariably met with the overwhelming smell of sulphur or, as the kids call it, rotten eggs and farts. After light-heartedly blaming each other for the smell for a few minutes, the smell fades away. In reality, the smell is still there but our sense of proprioception has masked it, subconsciously moving it into the background. Remarkably, this suppression does not affect the overall sense of smell. Stop to smell some roses or stop by a bakery and smell some freshly baked cookies, and you’ll find you enjoy the scent even though the sulphur is still hanging in the air.

Proprioception allows us to listen to a single person talking in a crowded bar, separating their voice out from all the overlapping noise and confusion, something impossible to replicate with a microphone. As a tinnitus sufferer, I can’t help but wonder if proprioception is coming into play here as well. The phantom ringing a tinnitus sufferer hears appears be due to proprioception compensating for the physical loss of auditory input in the high ranges. As actual hearing loss occurs, the brain compensates by supplying the missing frequencies. Much to my dislike, it seems tinnitus is my mind trying to help me out. Thanks, mind

If someone loses there sense of proprioception the results can be quite disastrous. Simple tasks, like walking, become extremely difficult and require immense concentration. With retraining, the problem can be reduced, but they’ll never be able to cartwheel again. Extreme cases, known as the Dr. Strangelove syndrome or the alien hand syndrome, can be quite distressing for the patient and quite incredulous to those around them.

It shouldn’t be that surprising to us that we have more than five senses. In fact, wikipedia lists ten! It’s just that seeing, hearing, touching, smelling and tasting are so dominate we miss the subtleties associated with the others. Other animals, like fish, can sense electrical and magnetic fields in addition to these. It makes one wonder what senses an alien species might have after evolving somewhere other than this terrestrial orb.

You can test your sense of proprioception with some simple tricks that are great fun for kids and adults alike.

• Stand in an open doorway with your hands by your side and push outward on the door frame with your wrists for twenty seconds. Step out of the doorway and relax your arms and they should feel light and tend to float upward
• Grab a basketball and press it hard between your two hands for twenty seconds. Then place your hand on a flat surface and the tabletop will feel curved

OK, so they don’t work quite so well for everyone, but this is your sixth sense, your ability to be aware of spatial relationships in relation to your body.

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Peter Cawdron is the author of the acclaimed hard science fiction novel, Anomaly.