Watching “Ender’s Game” With My Science Goggles On

By Corey S. Powell | November 2, 2013 10:14 am

I get it: Ender’s Game is not a science movie, or even a hard sci-fi movie. In many ways it’s barely sci-fi at all, falling closer to the coming-of-age hero fantasy narratives of Percy Jackson or (ducking) The Phantom Menace. But it certainly contains plenty of science fiction tropes and settings, many of which dovetail with themes from other recent science fiction films. As I watched it, I was intrigued by these recurring elements, and by the ways they riff on–or contradict–recent scientific discoveries.

Ender Wiggin directs an epic space battle. Surely there's a better way. (Credit: Summit Entertainment)

Ender Wiggin directs an epic space battle. Surely there’s a better way. (Credit: Summit Entertainment)

Note that I’m referring only to the film, not the book. I’m not out to ruin anyone’s fun, so I’m avoiding spoilers as far as possible. I’m not here to write a critical review of Ender’s Game (it is entertaining for the younger audience, and let’s leave it at that). And my point is not to fact-check the movie, but to place it in the context of the things we actually know about biology, evolution, and the physics of other worlds. Science goggles engaged.

Why are aliens so thirsty? Aliens in the movies are always coming to Earth because they covet our water; they do it again in Ender’s Game. This theme dates back at least to the late 19th-century quasi-scientific studies of Percival Lowell, whose 1895 book Mars depicted the planet as a dry, dying world populated by aliens who had constructed enormous canals in an attempt to save their civilization.

Science goggles: Lowell turned out to be wrong about Mars in just about every way. The canals that he perceived were an optical illusion or a psychological delusion; Mars harbors no complex life forms, and its surface air pressure is so low that liquid water would instantly boil away. Nevertheless, his ideas inspired War of the Worlds, A Princess of Mars, the Martian Chronicles, and many sci-fi stories.

Interestingly, one of the big lessons of recent astronomical research is that water is really not rare at all. Many planets, satellites, and asteroids are full of water. The moon has water, and even Mercury seems to have water ice at its poles. Mars has enough moisture in its soil that you could potentially extract two pints of drinking water from each cubic foot of Mars dust. If you are a thirsty alien, there are much easier ways to get a drink than conquering Earth. Jupiter’s moon Europa is covered with a layer of water and ice roughly 100 miles thick, a total volume considerably more than Earth’s oceans.

What’s so great about Earth? Let’s assume Ender’s Game got it wrong and aliens are not coming for our water. Earth is still an unusual planet. What might aliens be interested in here? Would they come to eat us, a la the Twilight Zone or the movie Signs?

Science goggles. Humans-as-food also seems highly unlikely. If aliens have the resources to travel between the stars and get to Earth, they surely have the resources to make food locally or raise a whole bunch of space cows It also seems quite likely that Earth life would be poisonous or indigestible to alien biology. What about other kinds of other basic resources? Again, probably not. Interstellar travel takes so much energy to travel that coming to Earth for basic resources would be like building a billion-dollar rocket to get you to Wal-Mart so you could steal some T-shirts.

The latest studies of planetary systems around other stars seem to hint that planets like ours–liquid water, oxygen atmosphere–may be rare, although the data we have so far are extremely sketchy. But if Earthlike worlds are rare, coming here to colonize the planet seems at least conceptually justifiable. Another possibility is tourism (including hunting tourism, as in the Predator movies), or scientific study (in which careless visitors might not even realize they are trampling on us). Humans do these things. Aliens might too.

What would aliens really look like? [mild spoiler here] In Ender’s Game, as in many other recent sci-fi movies (such as Starship Troopers and Men in Black, even District 9) the aliens have insect-like physiology.

Science goggles. Insectoid aliens are an interesting possibility, one that shows some creative thinking: There is no reason that aliens would have to be mammals like us. Creatures that colonize and move from location to location would be natural space travelers. And although aliens need not have any kind of humanoid form, it is likely they would have heads, legs, eyes, and other familiar sensory structures, because such things have evolved repeatedly and independently on Earth.

The bad science in these insectoid aliens: A lot of them are basically giant bugs that look like scaled-up ants or grasshoppers. Such creatures would collapse under their own weight, because real structures don’t scale like that. Mass increases with the cube of volume, which is why elephants need thick legs whereas ants can make do with spindly limbs. And while we might recognize the aliens’ overall body plans, you can bet that any real creatures from another would look unlike anything on Earth. Blame movies like Them! for brainwashing both movie-makers and movie viewers into thinking giant ants actually make biomechanical sense.

One step takes Ender from 1-g to zero-g aboard a space station. Er...not quite. (Credit: Summit Entertainment)

One step takes Ender from 1-g to zero-g aboard a space station. Er…not quite. (Credit: Summit Entertainment)

Why is it so hard to get gravity right? Ender’s Game does make some good-faith effort to show how artificial gravity is created on a spinning ship. The move also correctly depicts how, in a non-spinning part of a space station, people experience weightlessness. This is a common science-fiction problem: It is difficult to create the special effect of weightlessness through large sections of a movie, and audiences find it distracting to see their characters floating around in weird and unfamiliar ways. Props to the movie Gravity for embracing this.

Science goggles. NASA experimented with (very slight) artificial gravity way back in 1966 on the Gemini 11 mission. But the basic dynamics of what it’s like to feel fake gravity and weightlessness in space, which 2001: A Space Odyssey nailed perfectly 45 years ago, get very muddled in Ender’s Game. Nobody wants a lecture about centrifugal acceleration and rotating reference frames in a popcorn movie, but it sure would have been cool to see the elaborate acrobatics needed to shift from the high-gravity to low-gravity to zero-g sections of the space station. In a movie that is all about training and skill, that could have even become a dramatic plot element. Then again, even Gravity flubbed some key aspects of, er, gravity.

If space tourism really takes off in the next couple years, more and more people will know firsthand how gravity really works in free-fall. Even a near-space ride on a helium balloon could give tourists a taste of weightlessness. Or you can watch a live video feed from the International Space Station.

Where are the robots? This is something that puzzles me in many science fiction movies (and TV shows as well). Future civilizations that have the ability to build giant space stations and warp drives capable of interstellar travel still seem to do almost everything by hand. Even combat missions seem to depend primarily on human pilots–the whole Star Wars universe operates this way. [very mild spoiler] Most of the combat in Ender’s Game seems to involve pilots as well, even if they are mostly unseen.

Science goggles. The United States military already relies heavily on unmanned drones, and the idea of sending autonomous robots into combat is so real that the United Nations is currently debating measures to control it and the U.S. is working on the relevant technology. Putting people in the spaceships makes for better drama, of course, and sometimes is crucial to the plot (as in Battlestar Galactica). As a vision of future technology, though, piloted spaceships are a lot like the old 1960s sci-fi shows (Star Trek, notably) that didn’t consider things like mobile computing and the Internet.

One notable technology lesson from the past half century is that advances in computing happen much more quickly than advances in propulsion. There really has been only one notable advance in rocketry since the days of Apollo: solar-electric ion propulsion, currently used to send the Dawn spacecraft to Ceres and OSIRIS-REx to the near-Earth asteroid Bennu (and the upcoming BepiColumbo mission to Mercury). By the time we are able to travel to other stars–assuming that is even possible on a human timescale–we’ll probably have ships with artificial intelligence that makes it unnecessary to send people unless we want to. In fact, robots might become our real explorers while we watch the footage down here on Earth, or maybe human minds will be uploaded as software.

The secret Achilles heel of interstellar sci-fi stories: energy. Almost all the fun things that people do in science fiction take a lot of energy. Iron Man’s flying suit is an energy hog, which is the #1 reason why nobody could build such a suit in real life. The kind of interstellar travel shown in Ender’s Game (and many, many other sci-fi worlds), which allows near-instantaneous travel across light years of space, depends on discoveries that go beyond the known laws of physics. But it is clear that no matter how they work, they would require a fantastic amount of energy.

Voyager 1 is the only true interstellar spacecraft humans have created. (Credit: NASA)

Voyager 1 is the only true interstellar spacecraft humans have created. (Credit: NASA)

Science goggles. How much energy? Propulsion guru Marc Mills estimates that sending an unmanned, slower-than-light probe to the nearest star would take on the order of a million times as much energy as the entire planet generates today. Even the less ambitious parts of the sci-fi landscape are challenging. It is easy to imagine how to build giant space stations or robot soldiers; surprisingly, it is much harder to imagine how we would power these things.

The flip side is that any civilization that did figure out how to tap into an essentially limitless supply of power could satisfy almost any need without raiding other worlds. That gets back to my first two points, about water and other resources. With enough power to reach the stars, you could probably convert Mars into a habitable planet, or build giant space colonies, or fabricate just about any conceivable thing you could want out of moon dust or stray asteroids.

Sorry, Ender. Star Trek gets this one right: If you have access to the kind of energy needed to travel from star to star, you will be exploring (aka, seeking out “new life and new civilizations”) or defending your territory, not scrounging around for basic resources.

Follow me on Twitter: @coreyspowell

  • Dante Lauretta

    Note: OSIRIS-REx does not use an ion-drive propulsion system. It uses a chemical system – hydrazine mono-propellant heated over a catalyst bed – like most other planetary spacecraft.

    • coreyspowell

      My apologies for the error, and thank you for the correction. I realize now I was thinking of the Japanese Hayabusa mission and mistakenly conflated the two. I’ve struck out the error above, and added a reference to an upcoming mission that really *will* use ion propulsion.

      • Klae A. Klevenger

        Thank you for taking the responsibility for your writing and correcting yourself when you are wrong. Neuroskeptic could learn something from you.

  • Ben Mancini

    While resource-gathering may not be a compelling reason for alien invasion, peaceful exploration isn’t necessarily the only alternative. A couple scenarios come to mind — “clash of civilizations” — i.e. destroy you before you destroy us (cf: Old Man’s War), or religion-like craziness (cf: DW’s Daleks or Halo’s Covenant). Ultimately, too, an intelligence that evolved totally separate from earth life would likely be less like the vaguely humanoid minds of Star Wars or even Ender’s Game — but so alien and incomprehensible to us that we’d likely find no possible way of understanding their motivations (cf: Lovecraft, Solaris, Rama).

  • h8r

    Statements like “Where are the robots? This is something that puzzles me in many science fiction movies (and TV shows as well)” suggest not only that you have not read the book, but also that you may not even fully understand that the movie is based on a book….

    • SixSixSix

      Why the aliens came here suggests he did not read the next book either. But so what? The article carefully pointed out that it dealt with the movie only. Card took six runs to get the screen play he wanted and freely admits the book could not be turned into a film: how do you portray the thoughts of a disturbed child on film?

      Total digression: heck, not even the holy Game of Thrones (my hyperbole) sticks entirely to the book. I certainly hope that it doesn’t stick to the last two largely waste of time books or at least drastically compresses the story line. Martin got two out of five right so far, the third being a mixed bag. Be interesting to see how the TV series deals with the declining quality of the later books. Also, perhaps the final installments will pick up reach to the quality of the first two books in the series.

    • coreyspowell

      First sentence, second paragraph: “Note that I’m referring only to the film, not the book.”

      I’m talking about common science-fiction movie tropes in this piece, and Ender’s Game — regardless of its source material — shares many features with other recent films in the genre.

  • SixSixSix

    Give star trek a break. It did introduce the flip phone, featured talking computers, near limitless historical archives, machine translation, and inspired the generation who made these things into every commercial reality.

    “The flip side is that any civilization that did figure out how to tap
    into an essentially limitless supply of power could satisfy almost any
    need without raiding other worlds”. Now there is an amazing set of science blinders.

    Check out the recent editionof IEEE Spectrum that dealt with dwindling planetary resources of all major commodities, metals, hydrocarbons, rare earths, fresh water, etc. Free and infinitely abundant energy would make things much WORSE because we would hit resource limits even faster.

    The only hope for a civilization plagued by free and infinitely abundant energy would be to go scavenging off planet for more source materials before all that wonderful energy basically turned everything into pollution and high entropy, which ultimately may be the same thing.

    • Velvet Camel

      If you had a near limitless supply of energy, could you create a near limitless supply of matter? If E=mc2 then perhaps it is as simple as “tea, earl gray, hot.”

      • SixSixSix

        You would also create near limitless entropy around you. What are you going to do with that.? There is no energy transformation that does not cause an increase in entropy in one form or another. And more immediately, you would create near limitless pollution, trash, and refuse. Yes, you can be too powerful.

    • coreyspowell

      I hope it is clear that my commentary on Star Trek and other sci-fi TV and films comes from a place of deep affection. I love Star Trek, admire its visionary qualities, and appreciate how many scientists it has inspired. But I find it interesting that some aspects of the film’s future vision were quite prescient, while others completely misunderstood the emerging trends in science and technology.

      As for the question of resources: People have been predicting an imminent exhaustion of resources for at least two centuries. So here is my question to you: Do we have access to more resources than we did 200 year ago? Is our standard of living any better? Are cities less plagued by disease, and even by garbage?

      Through essentially all of human history, standard of living has correlated with access to energy. It is possible that the trend will reverse at some point–it is by no means a law of nature that it must continue–but for now my argument is based on longstanding empirical trend, while the Malthusian argument is based on faith and a history of failed predictions.

      • SixSixSix

        Star Trek was amazing and yet technological disruption produces all sorts of surprises. But seriously consider, is this kind of human civilization sustainable? Absolute not. Already much of Asia lives in terrible environmental filth in the name of economic growth. Air, water, ground pollution is not sustainable. The earth cannot take this level of abuse for much longer, even measured in human life spans. “Clean and/or free” energy its own right would only accelerate the disaster by enabling all the other bad habits more fully. Ask yourself, how much of the already depleted global fisheries do expect your grandchildren to have available to them?

        Climate disruption will not suffer this level of planetary abuse for much longer without severe hardship. The history of past prediction based upon poor theories does not protect from the reality of the threat, which come to think of it, is an odd place to take solace. I would suggest that you are extrapolating from a historical basis already known to be different from current and future conditions.

        • coreyspowell

          I’m just saying that you cannot draw trend lines from current events and blindly assume they will persist in their present form unchanged. That is the kind of thinking that has led to many of the past failed Malthusian predictions. Malthus himself predicted–more than 200 years ago!–that if war and disease didn’t thin out the population, then “gigantic inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world.”

          By straight extrapolation from 19th-century trends, today’s London would be uninhabitable, and there would not be a single tree left in the United States. Of course it is urgent to pay attention to today’s threats (pollution, overpopulation, resource exploitation, etc), because awareness of the threats is precisely the reason that the worst-case scenarios so often fail to materialize. But the argument that current society is unsustainable has been raised repeatedly for more than two centuries, even as overall human lifespan, health, and standard of living have continued to rise.

          • SixSixSix

            A bacterium culture can expand exponentially…until it hits the edge of the petri dish. Free fall feels good until you hit the earth. If you look at proximity to planetary collapse, all this “progress” has simply made the crash bigger.

            Environmental conditions are highly non-linear and full of sudden state changes at the boundary – checkout “chaos” theory (more accurately called dynamic system behavior). To quote from the above, “I’m just saying that you cannot draw trend lines from current events and blindly assume they will persist in their present form unchanged. ” Do you honestly think that the earth can bare this level of global abuse for another 100 years? 500? 1000? Pollution, climate disruption, over population have grown chronically and massively worse over the same time frame that you call “progress”.

            No way I want to live in China or India today or what awaits them shortly as they dig ever deeper into being the centers of global pollution, coal culture included.

  • ObeyMyBrain

    All the fighters in Ender’s Game were drones controlled by all the people wearing helmet displays in the command school at the end. Yes there were humans on the capital ships but not the fighters. They flew very mechanical precise formations that looked robotic and not human controlled and (I think it was) Harrison Ford’s character that called them drones at one point.

    • Nazmul Hasan

      but when we see those capital ships blowing up into pieces, there were real people (or should have been) in there. This is explicitly mentioned in the books.

      • ObeyMyBrain

        yessss? That’s what I said. “Yes there were humans on the capital ships but not the fighters.” And that was specifically mentioned in the movie about both the drones and the capital ships.

        One of the main points of the article was, “Where are the drones” my answer was, “In the movie. All of the fighters were drones.”

  • myounger

    I believe that the one motivation of the buggers in Ender’s game was to destroy the other sentient race they were aware of, which does make sense as a reason to expend the gigantic amount of energy required to travel. Get them before they get us is all the motivation you need, if you realize there is another civilization out there that can travel to where you are, you face the decision to act first or not.

  • Richard Bottomley

    I see that the comments section on here is pretty old, but in case anyone’s still reading I have a question; would using the drones as a heat shield actually work? I understand that the heat of re-entry is due to the compression of air in front of the craft, so it seems conceivable, wondering what others think.


Out There

Notes from the far edge of space, astronomy, and physics.

About Corey S. Powell

Corey S. Powell is DISCOVER's Editor at Large and former Editor in Chief. Previously he has sat on the board of editors of Scientific American, taught science journalism at NYU, and been fired from NASA. Corey is the author of "20 Ways the World Could End," one of the first doomsday manuals, and "God in the Equation," an examination of the spiritual impulse in modern cosmology. He lives in Brooklyn, under nearly starless skies.


See More


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Collapse bottom bar