Archive for the ‘Avatar (2009 film)’ Category

Science Fiction Round 27: Evolution Does Not Work That Way

There is something that we’ve touched on in several previous posts, but I’d like to talk about in a bit more detail: how biological evolution as a process and evolutionary biology as a model of it are misrepresented in media in general and in science fiction in particular.  Again, almost all of what I’ve written here is not original.  And as you’ll see, the particular misunderstandings I’m discussing here are based on two problems: many people not understanding evolutionary biology, and the human tendency to assume intent and direction even in entirely random processes.

Evolution Works Only On Populations

Evolution.  You keep using that word.  It does not mean what you think it means.

Evolution. You keep using that word. It does not mean what you think it means.

No, individual organisms do not evolve.  Nor are acquired characteristics passed from creatures to their offspring.  And nor does evolution allow violations of the laws of physics.  Got it?

Evolution Has No Goals

It should be obvious, but evolution is not a conscious entity.  Evolution is simply the set of processes that drive changes in the frequency of inherited characteristics in populations over time.  This means that evolution has no goals and no design.  Crucially, humans in particular and intelligence in general are not intended outcomes of a system in which evolution can occur.  I’m thinking of Star Trek and the new Battlestar Galactica in particular here, but the same mistake is made in a lot of science fiction.

Likewise, while symbiotic and cooperative behavior can certainly evolve, nothing like the entire-biosphere-is-one-organism of Avatar or various other misunderstandings of the Gaia hypothesis can actually happen without comprehensive engineering – a system like that only works when imposed top-down on the whole biosphere, and since evolution has no goals all that can occur are bottom-up emergent properties.

Evolution Has No Direction

Since there is no goal to evolutionary processes, it isn’t the orderly progression from pond scum to bilateria to basal amniote to mammalia to simian to ape to human to glowing space being seen in 2001 and Babylon 5 and on far too many t-shirts.  Species aren’t “more evolved” or “less evolved” than one another.  All things currently alive on Earth (and a few things that are alive off of Earth) come from different lineages that have survived for the same amount of time (3.8 billion years, give or take).  Over 99.9% of species that have ever existed on Earth are now extinct – or rather the distribution of traits in any living descendants they had has changed to the point that interbreeding and producing fertile offspring with their ancestors would be impossible.  Either way, the current set of living organisms isn’t anything inherently special in evolutionary terms; we’re simply the current state of a constantly-changing and boundly-chaotic system.

Massively simplified phylogenetic tree, from the Interactive Tree of Life website ( ).  We all are buried in the "Animalia" line.  Note how similar we and all other animals are genetically and how different the microbes can be.

Massively simplified phylogenetic tree, from the Interactive Tree of Life website ( ). We all are buried in the “Animalia” line. Note how similar we and all other animals are and how different the microbes can be.  Genetically speaking, you and me and a slime mold have more in common than the slime mold does with blue-green algae.

And even the messiness of the phylogenetic tree above and the full version that it is drawn from only begins to capture the chaotic complexities of evolutionary processes.  For example, it takes no account of populations with incomplete divergence, where the definition of “species” gets fuzzy because creatures can still have offspring with one another – be those critters flowers or gulls forming ring species populations; bears that were thought to be several different species before genetic sequencing came in; or the various different clades of H. sapiens – the main H. sapiens sapiens plus neanderthalensis, Denisova, and possibly others that we all are descended from.

But the data this chart is based on illustrate something very important.  The chart is based on the genomes of the organisms concerned; charting the statistical similarity between the sequences of their component genes.  Those genes have changed in many different ways after the ancestral population of each pair of lineages split.  Sometimes, genetic information is copied.  Sometimes, it is added to.  And sometimes it is deleted.  Fundamentally, many of those alterations are random: a cosmic ray hit scatters a base pair; a DNA polymerase makes an error that is not corrected by a proofreader; and so on.  That makes them impossible to predict.  While you can put limits on the possible traits that could appear and spread in a population, there is no way to predict exactly what a population’s descendants will evolve into in the future (and if we were able to run history twice from the same starting point, we’d get two very different outcomes).  Nor can you say exactly what a population’s ancestors were like.  At best, you could do a statistical best-guess reconstruction.   There is no latent amphibian in your genome.

Evolution Is More Than Natural Selection

This one is really annoying, because it tends to show up among people who nominally have learned something of evolutionary biology.  Basically, it is the tendency to assume that every observed trait of every population must be the direct product of natural selection.

Certainly natural selection is important, even over relatively short timescales.  The spread of lactase-persistence genes in the human population over the last several thousand years is a classic example.  Even in populations where lactase production does not usually continue into adulthood, a few random people with mutations that keep it active are born.  In cultures where animals that can be used to produce dairy products have been domesticated, being able to eat those products gives a big advantage in terms of calorie and protein intake.  And so the lactase-persistence mutations that happened to be around when and where humans started keeping herds have spread throughout the population (although even now, most people worldwide don’t have lactase-persistence and many people who do continue to produce lactase in adulthood don’t produce it at the same level as in childhood).

But there are many common traits that haven’t become so due to natural selection.  Genetic drift means that an allelle or trait that is neutral or even somewhat negative in terms of whatever metric of fitness is being used can still spread throughout the population, simply by random fluctuations and sampling.  This is particularly relevant during population bottlenecks and when small populations split off from larger ones.  Among many other examples, the latter is why American Sign Language exists: there was a high incidence of hereditary deafness among the population of Martha’s Vineyard, primarily among the descendants of a few deaf immigrants in the late 17th and early 18th century.

Massively simplified model illustrating the phenomenon of genetic drift.

Massively simplified model illustrating the phenomenon of genetic drift.  Colors indicate different alleles, all of which have exactly the same fitness: each model organism has an equal chance of passing its allele to the next generation.  Initially, all organisms in the population have the same allele.  Occasional random mutations occur, one of which eventually dominates the population by random chance.  I ran the model forward 21 generations, at which point the new allele was universally fixed, but there is nothing special about that point.  In another 20 generations or so, it would most likely be replaced by something else.

Genetic hitchhiking means that alleles associated with a gene that is being selected for can increase in frequency even when they themselves provide no benefit.  And “associated” can simply mean “nearby on the same chromosome” – for example, sections of human chromosome 5 may have been selected for, but hitchhiking caused a nearby part of the chromosome carrying an allele that gives a genetic predisposition to Crohn’s disease to spread at the same time.

And exaptation means that an allele originally serving one purpose may be selected for or against for some other reason – some dinosaurs with unusual scales for better thermoregulation and showing off to one another found that they were useful when jumping, and we got flying birds.

This all means that we and most other lifeforms on Earth are carrying around a lot of baggage that no longer serves or never served any useful purpose – be that an unused appendix or endogenous retroviruses – because there is not any sufficient cost to their presence and/or sufficient benefit to their removal.  Bottom line: many things about humans and other life on Earth, and about any alien life that we might encounter, will be the legacy of random events and we should not construct just-so stories just because we are uncomfortable with being the outcomes of a chaotic system.

Evolution Is Not Fate

Related to much of above:

It’s particularly grating and harmful when “evolution made it so” or “it’s natural” is used to in an attempt to justify cultural innovations or in an attempt to defend harmful behavior by individual people and characters.  I could use Star Trek references again here, but there are far too many other examples in fiction – fantasy as well as scifi.

Here’s one: Orson Scott Card’s Ender’s Game setting fails all over the place because he creates characters that are defined almost entirely in terms of psychology by their supposed evolutionary history (although Card personally ambiguously endorses intelligent design).  The Hive-Queens are unable to recognize that individual humans are intelligent even after observing our behavior covertly for an extended period of time before invading – they only get the hint after they’ve gotten into a massive fight with humans.  That makes no sense.  Evolution is not fate, and anyone capable enough to be traveling over interstellar distances and establishing colonies on dozens of planets with their own local biospheres will be able to parse “not all intelligences are exactly like me”.  Card also extends his own personal bigotry to his characters, and this as a device to endorse his own particular and dangerously wrong ideas of sexual ethics, falsely claiming as “biological imperatives” things that are entirely the inventions of certain groups of humans.

Nor are such actively-harmful misunderstandings of evolution restricted to fiction.  Evolutionary psychology does contain some valid and important insights – such as where some cognitive biases come from – but it is also invoked in misguided attempts to excuse both harmful individual behavior and elements of current culture that are both recent in time and restricted in space.  One particularly absurd example, although it’s very far from the most harmful:  The claim that the current US-centered gendering of the color pink as feminine is due to Paleolithic foraging habits and therefore justified.  In fact, that’s only an invention of the last 60 years or so – and in the US, it was preceded by a few decades where pink (along with red) was seen as masculine.

I hope the problem here is abundantly clear.  “Evolution says so!” is being wrongly used to hold aspects of culture / behaviors above question.  First, evolution doesn’t say anythingno goals and no direction, remember?  And, second, evolution is not fate.  We not irrevocably bound to any particular culture or set of behaviors out of the incredibly wide range that we can choose from.  If we can change things to make the world a better place, we should do so – regardless of how the frequencies of different alleles changed among our ancestors.   It is dishonest and harmful to claim otherwise.

Fantasy League Round 10: A Better Avatar

2013/04/03 2 comments

There was a beautiful but terrible film with a bunch of blue aliens.  I am not going to talk about that one any more.  There was also a live-action film with the same characters, but that’s not it, either.

Avatar: The Last Airbender is a surprisingly good animated television series.  Some things were awesome.  Some things… make me wonder what just happened.  As ever, here there be spoilers.

(Also, Michael did some significant writing for this one, since he knows stuff about martial arts.)

This is a fan-made image, showing the main cast of characters.

This is a fan-made image (available here), showing the main cast of characters, roughly as they appear near the end of the seires.  The guy in the middle is Aang, the last airbender (at the time) and the Avatar.  No, the one with the staff, not the one with the fur.

The Bending


Bending in Avatar refers to four (or five) different sets of related styles of Supernatural Martial Arts, themed around the four Hellenic Classical Elements – air, water, earth, and fire.  The different societies in the Avatar world are based around primary use of one element: Fire Nation, Earth Kingdom, the Water Tribes, and the Air Nomads (of whom Aang is the sole survivor for a long time).  Despite the Hellenic division of the universe, the societies are predominately East-Asian themed: the Earth Kingdom is styled like classical China, the Fire Nation more like Meiji Japan, and the Air Nomads like Tibetan/Nepali Buddhists.  The Water Tribes are a bit stranger: predominately Yupik/Aleut/Inuit, but a group in the equatorial swamp was greatly divergent.


Katara, water bending prodigy and Aang’s eventual love interest, uses a water whip to knock down a circle of opponents. Compare her arm motions to the picture on the right.


Yang Ch’eng-fu, master of Yang-style tai chi, demonstrates the “Single Whip” posture circa 1930. Real-life applications include grabbing an oncoming opponent’s wrist with the right hand, rotating to the left, and pushing with the left hand against the opponent’s shoulder while pulling with the right. They go past you, with their forward motion partially redirected into a spin and ideally into a fall.  (Application described by Steven J. Ostro, 2007)

One of the most fun things about bending, and why Rachel asked me to write this section, is how it is animated.  The different elements are each associated with different real-life martial arts styles: water bending is based on various forms of tai chi (lots of redirection of motion), air bending on the less-well-known bāguàzhǎng (which focuses on evasion and smooth motions), fire bending on Northern Shaolin (emphasis on straight-line strikes), and earth bending on Hung Ga and related styles (deep solid stances).  Like real-life martial arts, there are local variations in each style.  This extends down to the level of individual characters, determined by their particular skills and who they were taught by.  This is most prominent in the main characters and antagonists, but even bit characters get stylistic touches – some of the Earth benders incorporate American wrestling moves.  Also like real-life martial arts, the techniques of bending aren’t restricted to humans.  Some animals use them as well.  Most prominently, there are flying bison, which stay airborne by air bending.  Aang has one, Appa, as his companion.  Appa is also the Gaang’s transportation (you see him above in the background).

The next cool thing is how bending is often exploited for mundane utility – water benders can do interesting healing tricks and build cities out of icebergs, the air benders had a global society based around towns that could only be accessed by flying, earth bending powers trains and heavy construction, fire bending becomes the basis of external combustion engines.  These interlocking uses of magical and mundane technologies are reflected in relatively high life-expectancy and quality-of-life for human cultures that we would otherwise consider to be just at the edge of the industrial revolution (that and bending is apparently good for physical fitness).

The writers also made an effort to ensure competitive balance.  Bending is only so capable (with the exception of the Avatars, who can move large islands around).  Non-bending characters can equal or exceed what benders alone can do, either by engineering – such as The Mechanist, who builds gliders and dirigibles – or by subterfuge or by appropriate application of non-magical skill.  The last sees the most air time in the show: super-accurate sword experts who can defeat all but the most powerful benders, knife-throwing to pin people in positions they can’t bend from, metal fans to wave fire bender flames out of the way, nerve strikes that temporarily paralyze and block bending.  The last is a bit of a stretch for mundane martial arts, and is described as “chi-blocking”, so perhaps it counts as a fifth sort of bending.

There are a couple of problems with how bending is implemented.  The most obvious is this: why is the Avatar the only one who can use more than one element?  This gets into the Hindu concept of an Avatar as a reincarnating personification of universal power and the idea of bodhisattvas in some Buddhist schools, but just by itself it doesn’t make much sense.  Zoku’s uncle Iroh (who is an awesome character) studied with water benders and incorporated some of their skills into his fire bending, although he did not learn how to bend water himself.  But he did learn how to deflect lightning.  Toph, the short Earth-bender punching things above, figures out how to bend metal.  The background material explains that some people born in one nation are able to bend the theme element of another nation and not that of their own (which means that Aang will not be the last airbender forever).  They usually immigrate or remain untrained and unable to use their power effectively.  But why aren’t there any double-element or triple-element benders around?

The second problem is cultural.  Why have the nations segregated themselves?  Why don’t we have a more integrated society with air benders carrying the mail and other high-speed packages and working search-and-rescue; water benders handling hospitals and ocean freight; earth benders doing construction and land freight; and fire benders dominating large sections of manufacturing and the restaurant industry?  Some of that could be justified historically, but given that the Avatars and the Four Nations have explicitly been around for over a thousand years, more cultural blending would be expected for the economics to be completely consistent.  Related to the economics: in the Avatar world, both bending and mundane martial arts skill are egalitarian.  The main Gaang has two young women and three young men, but the ratio becomes three to three when the recurring character Suki joins the group during the last few episodes.  Several of the most dangerous antagonists are also women.  Given this, why are the political and military leaderships of Fire, Earth, and Water still so male-dominated?  Air was apparently more egalitarian, but everyone but Aang is dead during the series.  We’ve touched on this problem before.

But even given those problems, Avatar still wins at world building in comparison to many other works, especially relative to other shows intended primarily for a young audience.


Character Development is Made of Win

I’m particularly impressed with how well the characters were developed.  For instance, Sokka, the kid with brains but no bending, is appropriately snarky, but occasionally frustrated by lacking the raw power of his friends.  He gradually transitions from being very goofy to having a more serious mien — though he never loses the sense of humor.  Toph’s frustration with her parents and her desire for independence, which causes friction with the group, also work well.  Even some of the minor characters have consistent appearance.  The most entertaining is the guy trying to sell cabbages… and whose cabbages keep getting destroyed in various unfortunate ways.  The appearance of airships is also nicely foreshadowed.

Zuko is particularly impressive.  Over the course of the series, he transitions (with the mentorship of his uncle Iroh) from a teenager desperate to earn back his honor and his father’s love by capturing the Avatar to working against his father to save the world.  There are a lot of bumps in the road, and I think it does a good job of illustrating the blurry line between good and evil.  He shows both kindness and anger towards others in his travels.  We learn he was loved by his mother, abused by his father, and constantly in conflict with his sister.  He shows considerable internal conflict about changing sides, and has the appropriately rough reception when he presents the other kids with his change of heart.  It takes all of the first two seasons and part of the third in order for him to get there.  The rapid heel face turns we often see in movies always strike me as a bit… difficult to swallow.  This more gradually transition is much easier to accept.

Wait, How Old Are These Kids?

Now, for the head-scratchers.  While our heroes were developing mentally, there was a certain lack of physical growth.

Perhaps this makes sense for Aang — after all, he was twelve when he got stuck in the glacier, so maybe his growth has been permanently stunted by the experience.  (Apparently this is actually canon, though it isn’t mentioned in the series.)  On the other hand, there’s no such excuse for the other characters.  Zuko may be done growing, but Sokka, Katara and Toph all start the series at around the age when they should be having a growth spurt.  So, why does Sokka stay so much shorter than his dad for the whole series?  Why does Toph, the youngest, stay so short relative to the other kids?

<michael>Related problem: the main character’s ages.  Aang is physically 12-13 during the series; Toph is younger; Katara, Sokka, and Zuko somewhat older.  But a lot happens during what is supposedly 12 months – crisscrossing the admittedly-small map many times, sieges and battles, near-death injuries and recoveries from them, lots of character development and changes in relationships, and Aang re-learning and mastering three styles of martial arts.  This is all too fast.  He learns fire bending last, but even so three weeks is simply not enough time to master a new set of motions.  If the series had progressed in near-real-time, covering three or four years in-universe during its original run, things would have worked better.  That would also have made the romantic sub-plots between Aang and Katara and Sokka and Suki more realistic, but would have made the lack of height changes more severe.</michael>

I See Dead People

Or, rather, we don’t.  Since this is primarily a kid’s show (despite being interesting enough for adults), we never see anybody actually die on-screen.

This is okay, except that in their various adventures and battles against the Fire Nation, it really looks like our heroes have almost certainly killed some — but act as though they haven’t.  Were there really no deaths in the Fire Nation ships you guys smacked, or the various fights against their soldiers, or when Aang went into Avatar super-powered mode at the North Pole, or when you assaulted the Fire Nation’s capital – smashing fortifications and tossing bombs into guard towers?  Really?

Thus, it comes across as very strange when Aang has severe reticence against killing the Fire Lord after confronting him.  He even says explicitly that he has never killed anyone before… when that is unlikely to be true, especially given the North Pole nastiness.  Perhaps he means “deliberately” killed someone?  It just doesn’t quite fit.

The Ending

And that makes the ending all the more jarring.  Where did that giant lion-turtle come from?  Sure, they got a mention a time or two earlier in the story, but the sudden appearance of energy-bending (“bending each other”) really feels like a deus ex machina so that Aang can just de-power Fire Lord Ozai instead of killing him.  It really feels like it came out of nowhere, especially since much of the discussion of plans earlier in the story focused on killing or defeating the Fire Lord.

This would have been much better if the ability to bend the energy of people had been mentioned… well, pretty much anywhere earlier in the story.  Some sort of interesting ancient legend from before there was an avatar, for instance.  That would have made this seem a bit less like a last-minute tweak to avoid having to kill a bad guy on-screen.

<michael>I propose that the mystic-energy-powered water bending healing and the chi-blocking nerve strikes were intended to be weaker derivatives of the energy-bending techniques, but that could have been better developed.  Tougher problem: was permanently de-powering Ozai actually necessary to ensure he would not pose a threat in the future?  If not, was it justified to do so?  When is it ethical to invade someone’s mind/brain and rip out the parts that let them do something extraordinary?  And what else can energy-bending do?</michael>

SciFi Round Twelve: Pocahontas in SPACE!!!!

2013/02/09 6 comments

Avatar (not the one with the last airbender) is one of the prettiest films I’ve come across.  Beautiful cinematography.  Nice constructed language for the aliens.

Now, it’s time to look for problems with the science and internal consistency.

It’ll be like shooting fish in a barrel, but let’s have a go at it anyway.


The blue alien is the alien "avatar" of the dude on the right.  He proceeds to learn how to be more awesome than the real aliens.  Oops.

The blue alien is the alien “avatar” of the dude on the right. He proceeds to learn how to be more awesome than the real aliens. Oops.

A Little Astronomy Goes A Long Way

Somewhere, something has gone horrible wrong.

And I’m not even referring to the outrageousness of naming a substance unobtainium, or the moon you’re visiting Pandora.  I’ll try not to open that box too much.

There is so much wrong here, it’s hard to know where to start.  According to the movie (and the wiki), Pandora is a moon around the gas giant Polyphemus, which in turn is in orbit around Alpha Centauri A.  First off, as I mentioned in an earlier post, there is no such gas giant in the Alpha Cen system.  (Though there’s a much smaller, hot rock orbiting Alpha Cen B.)

The next problem is that Alpha Cen A’s habitable zone is further out than that of Alpha Cen B.  Planets in the habitable zone of the latter may have stable orbits.  There could even be an Earth-like planet, which, while not detected yet, hasn’t been ruled out.  (They’re looking.)  However, planets in the habitable zone of Alpha Cen A are probably not going to be in stable orbits.  They would be further out, and more easily perturbed into unfortunate orbits (or possibly even ejected) by encounters with Alpha Cen B.

Next up: Polyphemus is smaller than Jupiter, but Pandora is about the size of Earth.  This… doesn’t really work.  Jupiter’s largest moon, Ganymede, is bigger than Mercury, but much smaller than Mars… and not really close to Earth-size.  Pandora is too big, or Polyphemus is too small.  Or something.

For bonus points, gas giants and their moons presumably formed outside the “ice line.”  That means, they were cool enough that not many volatile elements were warmed up and vaporized off.  “Volatiles” includes water.  This is why so many of the outer moon are icy, and why comets actually spend most of their time in the outer solar system.  (If they didn’t, they wouldn’t have any ice left for the sun to bake off to make them into comets.)  Pandora should be an iceball or a water-world, not rocky.

There are even more astronomical issues in the wiki details, but I think I’d better stop while I’m ahead.

The Unobtainium

This doesn’t make much sense either, alas.

Supposedly, unobtainium (oh, geez, the name, the name…) is a room-temperature superconductor necessary for the production of maximally high-speed, but sub-light, interstellar travel.  Unobtainium is available on Pandora, but not Earth.  (The first expeditions, without ships using unobtainium, were slower and generally much less awesome.)

Problem one:

The floating rocks.  These are awesome.  They also don’t work.  There’s an issue with stability.  The setup is essentially a mountain sitting on a big unobtainium magnet, which then floats in Pandora’s magnetic field.  You then have to avoid having your magnet flip over and stick itself to the ground with the same amount of force.  So all the mountains have to be bottom-heavy, to avoid flipping.  And too much of a perturbation – like, say, collisions or explosions – could still knock them over.

You can get around that by having a superconductor and an external magnetic field, but those would have to be both very large solid chunks of superconductor and an absurdly powerful magnetic field to hold the mountains up.  A couple of different estimates by me and Michael suggest that for a small-ish mountain made of superconducting material, you’d need at least 5 Tesla of magnetic field to hold it up.

That’s five TESLA.  At least.  Supposedly from Pandora’s magnetic field.  For comparison, Earth’s magnetic field is about 30-60 µT.  Yes, that’s micro-Tesla.  3e-5 T.  Way, way less than 5 T.  Sunspots?  Still only up to a few times 0.1 T.  But there is something on Earth that makes that high a magnetic field.

It’s called an MRI machine.

When they wheel people into one of those things, they have you take off everything made of metal.  Now, rotating in a magnetic field or sitting in a changing magnetic field will induce currents, more easily in better conductors.  Larger currents get produced by larger motions/changes in magnetic field.  Anything made of metal that goes in the machine will conduct a current induced by the magnetic field… and dissipate heat… which can be uncomfortable.  Plus, the same thing can happen for the human body itself, which is part of the reason why they wheel people in slowly.  Another part (as discovered by one of Michael’s cousins) is that neurons have conducting parts, too.  Turn your head too quickly while in a few-Tesla magnetic field, and you see lights, taste metal, and other funny sensory effects.  (Don’t worry, he was fine shortly afterwards.)

Suffice it to say, if Pandora really had a 5 T field on its surface under the Hallelujah Mountains, communications and electronics failures are the small problems.  The presence of the mountains themselves will make the field very nonuniform.  So, you get weird effects on your brain every time you move, and all the metal surfaces of, for instance, your helicopter are getting heated to high temperatures by induced currents.  Ouch.

Problem two:

According to the backstory, unobtainium was produced on Pandora by the impact of a Mars-sized object onto Pandora early in its formation.  Unobtainium (whatever weird crystal it actually is) was produced by the high pressure and temperature, and interaction with Polyphemus’s magnetic field.  And this is why it’s not found on Earth, and can’t be manufactured.

That’s happened on Earth.  It’s called the moon-forming impact.  A hypothesized Mars-sized object called Theia smacked the Earth about four-and-a-half billion years ago.  The material that blew off of Earth into orbit eventually coalesced into the moon.

For bonus points, such high temperatures and pressures as in that kind of impact… can be produced in a lab.  (You should use either an impact gun or a diamond anvil cell.)  So, if what they say about the production of unobtainium is correct, we could make the stuff.  It’d take some work to scale it up for industrial purposes, but hey, given how expensive the stuff is, it may well be worth it.  Speaking of money…

Unobtainable Economics

The economy here is impossible, too.  Supposedly, unobtainium is worth $20,000,000/kg, unrefined.  For comparison, platinum, an important catalyst on Earth in the real world, is worth about $55,000/kg, as an essentially pure metal.  And according to my old CRC manual from 2005, plutonium is worth about $5/mg, or $5,000,000/kg.  In other words, unobtainium is four times as valuable as plutonium.  (I’m assuming that inflation must have flatlined somewhere, to make the dollar costs for things in the far future equivalent to now.)

Now, in the future, unobtainium is supposedly powering both the starships used to obtain unobtainium, as well as handling Earth’s power needs.  So, if somebody running a power plant can get at least 4 times the energy with the same amount of unobtainium as plutonium, plus it has less trouble with radiation and toxicity, well, win.

But what about our sellers?  In other words — what are the shipping costs for unobtainium from Pandora to Earth?  The description of their interstellar craft apparently includes both a solar sail and a pair of matter-antimatter engines.  (What? Antimatter?  Where are they getting that?  … never mind.  I’d better stop asking questions.)

Nonetheless, let’s assume that the ship going back has minimal weight, other than fuel and unobtainium.  It travels at 0.7 c, and is powered by matter-antimatter annihilation.  So, for the rocket equation, let’s assume that our exhaust is traveling at the speed of light.  Lots of gamma-rays out the back end.  In the end, you get a ratio of initial mass (fuel plus payload) to final mass of m_0/m_1=exp(arctanh(0.7))=2.4 to accelerate to 0.7 c.  Then you have to spend just as much of your current mass to slow back down again.  So, for every kg of unobtainium you send to Earth, you must expend a minimum of 4.7 kg of fuel, half of which is antimatter.

At present, antimatter is only fleetingly produced in particle accelerators.  Via Wikipedia — current world production of antimatter is less than 10 ng/year.  At a cost of about $10,000,000,000,000,000,000/kg.  That’s $10^19.  $10 quintillion dollars.  Give or take some.  But we need the total cost of antimatter to be less than about $8 million/kg, and also industrial scale production, or else this won’t work.  Especially given that there will be inefficiencies in production, and the ship isn’t a big lump of pure ore.  You need things like space for the crew… containment for the antimatter…

In other words, you need antimatter to be way cheaper than unobtainium to make the operation worth it.  This is a problem.

Of course, all this is for naught once some clever person decides to get rich by making the stuff at home.

Pandoran Ecology

Pandora really has the Gaia thing going.  Now, coevolution is a real thing.  Certain hummingbirds with hugely long beaks that can only drink from, and thus pollinate, certain kinds of flowers are an example.  They develop a unique connection because each is dependent on the other, and a change in one will tend to promote a reasonable change in the other to maintain the beneficial relationship.

The world-tree connection to what seems like every large animal on the planet, and which allows connections between those animals… is a bit much.  Earth has no examples of such strong symbiosis among so many complex species by a related mechanism.  I can’t think of any such tight, mutually beneficial tie between anything more than pairs of species.  Especially since… some of them also prey on each other.  Food webs?  Sure, those happen, but the fundamental bond between the animals on Pandora is quite different.  Plus, the bonds are only ever made between the forest or the Na’vi and the animals.  Bonds between animals are never shown.

I might have bought it if it was just the trees having an emergent consciousness.  With everything so directly connected by the brain-wire-worm-things, yet lacking stronger evidence, I can only strongly suspect that the Pandoran forest and ecosystem are artificially constructed to a large degree.

The Plot

I have no words.

Okay, I lied.  I have a few.  In short:

If I can accurately summarize your plot as Pocahontas in SPACE, and your villains are all stereotypically narrow-minded corporate tools, you should consider changing your plot.

Fantasy League Round 5: Fashion Failure

2012/10/30 8 comments

Sometimes, the clothes of the characters on the silver screen are awesome.  And sometimes they’re just ridiculous.

Straight to the Heart

This is one of my pet peeves, as it seems to ignore the reason why armor was invented.

To illustrate — which of these two characters is going to have more issues with projectile weapons and pointy objects aimed at their chest?

That’s what I thought.  The reasons for this from a media point of view are rather obvious: showing off a woman’s skin apparently attracts viewers’ and players’ attention.  Nonetheless, it’s obvious why armor like that was never used back in the real world.  The reasons for its use in media are, perhaps, just as obvious. Everybody knows that all gamers are straight males, and no women ever deign to touch a keyboard </sarcasm>.

Though it’s usually the women in the minimalist armor (consider Xena, Warrior Princess, or any number of other shows), they’re hardly the only ones.  Barbarian types especially are also subject to this.  (That’s even when you exclude things like Captain Kirk strategically ripping his shirt.)

Even if that’s their non-fighting gear, wouldn’t they get cold eventually?

Some of the Wheel of Time books by Robert Jordan include some bodyguards with precisely this kind of armor to make people think they’re less skilled than they actually are.  It seems to me that you’d rather give off that aura of ineffectiveness by means other than making it easier to be injured.  At least when this shows up in the Belgariad books by David Eddings, the queen’s armor is deliberately ornamental — the better to look awesome while giving orders to the army.


Similarly, it’s best to have appropriate shoes for the task at hand.

I don’t think I’ve seen anybody in film wearing shoes this bad. On the other hand, these shoes may actually be real…

As an example, in Sky Captain and the World of Tomorrow, our intrepid reporter spends the entire movie, except for a brief stint in the mountains, wearing high heels.  This is manifestly not a good idea.  At least in that movie, they make a point of mentioning (and demonstrating) how the high heels are a bad idea.  Given the number of times the lady characters end up having trouble running, or tripping over their own three-inch-heels…

In other cases?  Many of the women in Star Trek are only ever seen wearing high heels — most egregiously in the original series and Seven of Nine in Voyager.  Then again, maybe they’re trying to make a statement.  “She’s so awesome, she can outrun and outgun you despite the high heels”.

Of course, there are also alternative uses for high heels.  In most cases, I suspect using high heels as a weapon wouldn’t work especially well — they’re not made for handling that kind of stress, and given that most of them aren’t knife-sharp, it would take quite a bit of effort to impale somebody with them.  That said, stomping on somebody’s toes with them would work pretty well.

No Capes!

This is Stratogale, briefly mentioned in The Incredibles. Moments after this image was taken, the drag from her cape caused her to be sucked into the plane’s jet engine.

Capes are also on the list of fashion no-nos.  The Incredibles has a whole sequence of unfortunate superheroes who meet their doom via cape-related issues, courtesy of Edna Mode.  The fundamental problem with capes is that they get stuck in stuff, caught in stuff, grabbed by your nemesis and used to fling you across the room, and so on.

It’s not just superheroes, either.  The sorcerer and evil overlord types also frequently sport capes or long fancy robes, which film and novel even occasionally have be a demonstrable problem.  But most of the time, they manage to get away with it somehow.  Consider all the fighting in long, flowing robes that the Jedi do in Star Wars.  Darth Vader has a cape, too.  And, when Industrial Light and Magic was animating Yoda showing his stuff in the prequel films, the animators found handling his robes tricky — making sure they looked cool and like they weren’t going to get tangled and trip him.

Edna Mode knows her fashion.

I still think a detachable cape could be handy, though, given the utility of using clothing to avoid getting caught.


To quote the first item on the Evil Overlord List:  “My Legions of Terror will have helmets with clear plexiglass visors, not face-concealing ones.”

This is commonly done to the mooks in movies and so forth for the simple reason that, when we can’t see their faces, we can’t sympathize.  These are the faceless Legions of Terror, and thus morally acceptable targets, not people with a family who’re just doing their job as a guard.  It also helps in that you don’t need as many extras to portray your legions.

In practice, this means that the guards can’t recognize each other on sight.  A common heroic tactic is to knock out or kill an unlucky guard, steal his clothes, and bluff to get into the fortress of doom.

Nazgûl. Face-concealment is perhaps less relevant, since it’s not clear they have faces. On the other hand, since they can’t really see, it’s not clear why they have the big opening for their nonexistent faces. Smelling out his quarry, perhaps.  Regardless, that comes back to bite this guy later.

The other side of the coin is that, oftentimes, the hero doesn’t wear a helmet.

Avatar (with the blue aliens) actually manages to get this somewhat right.  The humans are always wearing helmets so they can breathe — with nice clear faceplates so we can identify them.  (The Na’vi don’t bother with them, though.  Or much armor, for that matter.)

Otherwise, our heroic SWAT team member is the only one without a helmet.  Real SWAT teams?  Everybody has a helmet, armor, and all the other appropriate gear.  Detectives without helmets try to stay back and out of the way when the situation goes south.  After all, dealing with the dangerous parts is what SWAT teams are for.

On the other hand, the best example of helmet fail is Star Wars.  The Jedi?  No helmets.  (Also no armor, but it seems that armor isn’t much help against lightsabers.  Personal force fields, on the other hand, would be nice.)  Stormtrooper helmets also fail badly on this front.  They’re face-concealing and, according to one character who… borrows… a helmet, it’s actually pretty hard to see, too.

Of course, they’re not terribly effective anyway.

And if you’re confused, you need to watch Star Wars: Return of the Jedi.

SciFi Round Seven: Alpha Centauri

2012/10/25 10 comments

There’s a planet at Alpha Centauri.  And that’s just too cool not to follow up.  (For those of you who may want more technical information than the first link, the full Nature article is here… though it may take a subscription to see the whole thing.)

In honor of that discovery, let’s see how well some fictional accounts of Alpha Centauri stack up.  It’s a popular system to consider, since the stars at Alpha Centauri are the closest to Earth (other than Sol – aka “The Sun”) at a mere 4.4 light-years.  I’ll only be hitting a few examples, but oddly enough, Wikipedia has an extensive listing if you want to see them all…

Alpha Centauri Is More Than One Star

I was shocked to see this mentioned on the aforementioned Wikipedia page, but apparently some authors think that Alpha Centauri is only one star.  I have the good fortune to not have read any of these; I would have been very upset by them.

While not obvious to the naked eye (or authors from the northern hemisphere who don’t see it at all), Alpha Centauri is composed of two stars.  The larger, Alpha Centauri A, is a spectral type G2V, the same as the sun, has a slightly larger mass and slightly brighter.  Alpha Centauri B is type K2V, and is noticeably cooler and dimmer than the Sun, and has about 90% of the Sun’s mass.  The two stars are close enough in mass that the system’s center of mass is well between the two stars, not near the center of one or the other.  Their orbit is eccentric, with the distance between the two stars varying between roughly 10 and 50 AU.  For scale, that closest pass is about the distance between the Sun and Saturn.  There’s a nice animation of this, along with other information, which also shows an estimate for where the habitable zones of the stars may lie.

On top of the bright binary, there’s a third, even dimmer star called Proxima Centauri (or sometimes Alpha Centauri C).  It orbits around Alpha Centauri at a distance of about 15,000 AU.  Its spectral type is M5.5Ve — at a bit over a tenth of the Sun’s mass, it’s much dimmer, cooler, and redder than the Sun or Alpha Centauri AB.  The “e” means it’s an actively flaring star.  More on that later.

Moving In

Sometimes it’s only mentioned in passing, but fictionally speaking, Alpha Cen is a common waypoint or colonization target.  It gets mentioned as such, and occasionally featured, in such things as Star Trek, Lost in Space, Buck Rogers, Doctor Who… the list goes on.  A couple of books that mention or feature Alpha Centauri are The Songs of Distant Earth by Arthur C. Clark and Foundation and Earth by Isaac Asimov.  In the movie Avatar, the moon Pandora orbits a gas giant which in turn orbits Alpha Cen A.  Sending a colony ship there is a method of winning the game in Civilization, and it’s the name of the game Alpha Centauri.  Typically, these works imply or require the presence of at least one habitable planet orbiting either A or B.

The recently discovered planet is Alpha Centauri Bb.  It has a mass somewhat greater than Earth’s, and orbits Bb at a radius of 0.04 AU.  Despite the fact that B is dimmer than the Sun, that means this little planet is baked to a surface temperature of at least 1500 K (depending on its albedo and atmosphere).  That’s hot enough to melt silicate rocks, and is at least twice as hot as Venus (which averages 735 K).  Odds of anything living there are pretty slim.

Artist’s conception of Alpha Cen Bb, which really needs a better name, in orbit around Alpha Cen B. The color scale is logarithmic, with brightness ranging over a factor of many trillions. Alpha Cen B is ~100,000 times brighter than Alpha Cen A as seen from Bb, the Sun is not quite a billion times fainter than Alpha Cen A, and the galactic plane is fainter still.

Because Alpha Centauri is so close, there’s enough data to give good limits on what other planets could be in the system.  Anything habitable must be orbiting either A or B relatively closely in order to be warm enough and to avoid having its orbit perturbed too much by the other star — but not too closely.  The combination of these two requirements makes it difficult for a planet to stay in Alpha Cen A’s habitable zone — it’s likely to get scattered out by B.  This may be a problem for works that put the habitable planet around A, such as Foundation and Earth.  B, on the other hand, may have less trouble with this, since its habitable zone is closer in.

Planets far enough out to orbit outside the AB pair would be too cold.  C is an unlikely candidate — it’s so small that any planet close enough to be warm enough for life would be close enough to be seriously zapped by radiation from the flares, which would (probably) erode its atmosphere.

Back to Avatar.  The moon Pandora orbits a gas giant, which orbits A.  Even assuming it gets away with orbiting A, there’s another problem.  Despite some false alarms, current limits indicate that there are no gas giants or brown dwarfs anywhere close to A, B or C.  Pandora doesn’t exist.  (And who names their moon Pandora, anyway?  But we’ll cover Avatar another day.)

On the other hand, that leaves plenty of room for speculation — smaller, rocky, habitable planets are possible, and more plausible around B.  The stars in the system are also older than the Sun, which means there’s been plenty of time for life to develop…


If the aliens are the technologically primitive (no radio) Na’vi, it’s pretty obvious why we haven’t heard from them yet.  Or they could all be a hundred years dead.   On the other hand, if we’re talking about aliens like the fithp in Footfall (by Larry Niven and Jerry Pournelle), then we’ve got a problem.

Contact with aliens from Alpha Cen is another common theme, with technologically advanced aliens an option.  In Footfall, they’re in the form of an unusually plausible group of alien invaders.

There’s just one problem.  We’ve been putting out radio signals for over a century, and relatively strong ones for television broadcasts for over seventy years now.  Those signals, while usually not decipherable, are still detectable and clearly artificial for a sphere sixty or seventy light-years in radius and expanding.  If we ourselves were sitting at Alpha Centuari, with our current technology, we could unambiguously detect those radio signals and notice both Earth and the fact that it’s inhabited.

By the same token, if Earth with all its radio chatter were orbiting Alpha Cen B in the habitable zone… we’d have heard them by now.  At least one of the books listed in Wikipedia (Factory Humanity) seems to get this right — contact with aliens at Alpha Cen is established first via radio.  Why we didn’t hear the fithp before they decided to take a detour through our solar system isn’t clearly explained.  Maybe they’ve replaced all their radio tech with subspace transponders.

Either that, or they’ve seen us, and are deliberately hiding.  Just like the Martians.  Insert your conspiracy theory here.