When I started my original series of posts on space battles, I speculated about what a combat-spacecraft designer might want to do in order to make a vehicle that could avoid enemy detection:
It would make sense to build their outer hulls in a faceted manner, to reduce their radar cross-section. Basically, picture a bigger, armored version of the lunar module.
Almost immediately, I got some feedback pointing me to the “Project Rho” website, which declares quite bluntly that “there ain’t no stealth in space.” The argument goes basically like this: any device you put on a spacecraft has to obey the second law of thermodynamics, which means that it generates waste heat. This heat will raise the temperature of your spacecraft well above the background temperature of ambient space (about 2.7 Kelvin). Therefore, the spacecraft will radiate and will be visible to infrared sensors, no matter what. Therefore, stealth combat spacecraft are impossible.
This argument is fundamentally sound. The principles are correct: you can build a detector that could locate any spacecraft. What I don’t like about this argument is its implied definition of the word “stealth” as “total invisibility.” Yes, it is possible that the detector you build will locate a stealthy space-fighter eventually. That clock is always ticking. But your adversary’s stealthiness can still pay off – if they get to launch their missiles before you spot them!
Later on, when I revisited space-battle physics, I went into a little more detail about possible stealthing technologies for spacecraft. In another post, I thought about some of the thermal concerns our hypothetical space-fighter designer would run into in trying to make the fighter hard to detect.
But the proof, as they say, is in the pudding.
There’s a military aphorism (Wikipedia tells me that Helmuth von Moltke is responsible) that battle plans never survive contact with the enemy. I suspect that, for all anyone’s speculations about what can, cannot, will, will not, or might happen in space combat, if we ever did find ourselves in a space war we would very quickly learn an entirely different set of guiding principles. Whether or not stealth spacecraft are possible will be apparent then, after the fact, no matter what arguments we make today.
However, we can get some insight by asking the question: do any stealth spacecraft exist today?
The answer, as it turns out, is “yes.”
Weather permitting, we are coming up on the launch of a Delta IV Heavy – a gargantuan behemoth leviathan giant of a rocket – carrying a National Reconnaissance Office “spy” satellite with the cryptic designation of NROL-15. Quoting a civilian military space analyst, AmericaSpace reports that the vehicle
is likely the No. 3 Misty stealth version of the Advanced KH-11 digital imaging reconnaissance satellite. It is designed to operate totally undetected in about a 435 mi. high orbit.
The article includes some description (or speculation?) about the physical appearance of the stealth spacecraft, too:
Looking somewhat like a stubby Hubble space telescope stuffed in an giant F-117 stealth fighter with diverse angles to reflect radar signals in directions other than back to receivers on the ground, Misty 3 is also covered in deep black materials designed to absorb so much light that it can not be tracked optically from the ground.
These design aspects are a huge challenge for a satellite that must also deploy solar arrays to generate electrical power and have reflective surfaces to reject heat. … The satellite may actually change shape to reflect heat when not over hostile countries trying to break its cover.
Apparently, there may also be some tricky maneuvering by the launch vehicle – to disguise the final orbit trajectory of the satellite. There is some speculation at the end of the article about the various options the vehicle might take to pull off that feat of obfuscation.
The bottom line for science fiction: cloaking devices are probably not going to work. But are stealth spacecraft possible or not? Well…we’re already doing it.
Well, since I just had some discussion about orbits and other fundamental physical concepts in science fiction, here’s a short scene I’ve been sitting on. It’s set in the Cathedral Galaxy, and I’m not quite sure what I want to do with it yet.
~
The Kite stretches his solar wings wide, spanning over five hundred meters. He fans out his array of electromagnetic membranes, thermal structures, transceiver antennae, and weapon emitters, flourishing. The Kite’s voice booms out over the electromagnetic spectrum, mingling with the others in the Coliseum, as they announce themselves to the assembled spectators:
“In salute, we die and live by the will of the Imperium!”
The Kite pulls one solar wing out from the light flux to tack. He wheels around, scanning and assessing his competitors. He catalogues their capabilities but pays special attention to their faces – distended from all the grafts and alterations, stone-gray and glassy-eyed from the environmental treatments, yet still faces. The younger competitors growl and sneer at him, while the more experienced repay his cool appraisal in kind. Today, The Tiger and The Worm worry him.
Silence falls across the EM bands, leaving The Kite with only the intermittent discharges from the Coliseum walls. His stomach (though no longer really a stomach) lurches in anticipation. A moment drags on in the flickering silvery shell of the Coliseum, buried in the sparse mist of an orange nebula. This could be the day, thinks The Kite, when I die. Again.
The call:“Begin!”
The Kite pulses an electromagnetic field, launching himself away from the spherical inner surface of the Coliseum. The others do the same. Continue reading In the Arena→
Yesterday I was invited to give a presentation to the Global Physics Department, and online group of college and high school physics educators moderated by Prof. Andy Rundquist from Hamline University. The group gathers to hear virtual speakers on math, physics, science, and education on a weekly basis. Andy found my blog (hi!) and asked me to work up a presentation on science and its presence (or absence) in science fiction. You can see the recording here. (There are lots of other interesting presentations on the site, too.)
I spent a while thinking about the approach I wanted to take with this presentation. Of course, the easiest thing to do would have been to pick some choice examples from science fiction and pick them apart, criticizing the presence of sound in space or starships that move like boats and airplanes. I did a little of that, but I also wanted to bring up some other approaches that might encourage students to explore the intersections of science and science fiction, including looking at some of the things that science fiction gets mostly “right,” examining what it would take to give us science-fiction gadgetry using current knowledge, and trying to extrapolate realistic scenarios using scratch paper and our imaginations.
All in all, I think it was a fun evening – but I barely scratched the surface! My only “disappointment” was that it would have been fantastic to really open things up for discussion at the end. But with a topic so rich, it’s hard not to run into the time limit!
One of the problems with having just watched a whole lot of Star Trek is that, while I like a lot of the characters and plots and ideals, it’s a poster show for demonstrating some of the biggest scientific problems in modern science fiction. So, without further ado, I break a long silence to present my Top 3 Science Errors in Sci-Fi.
#1: Sensors
If you are the captain on the bridge of a Star Trek ship, you have the advantage of being well-informed beyond the limits of physical possibility. Your science and tactical officers can consult the Sensors and instantly list for you every object within a few light years. They can tell you what each object is made of. They can give you a map of a planet surface, or approach a never-encountered-before alien spaceship and produce an interior schematic. They can rattle off the number, species, sentience, and state of health of every living thing on a planet. They can tell you what systems are active on an enemy ship. They can even quote for you what the enemy ship’s computers are calculating.
Decades worth of scientific data-gathering and interpretation, happening in an instant
It might seen like “sensors” capable of many of these feats are plausible, given some of the technologies and techniques available to us today. We have telescopes that conduct all-sky surveys and see billions of light-years; so why not give Starfleet captains an immediate cosmic census? We can do spectroscopy to determine a substance’s constituent elements remotely. And we can detect electromagnetic signals, which might emanate from even the smallest electrical circuits. But what’s missing from this picture is the presence of uncertainty, noise, and time delays, all of which make measurements harder – and make the conclusions you can draw from those measurements much less certain. At the very most, when Spock or Data or Dax quotes the composition of a strange starship, they should include a measurement of probability with each component – and those probabilities should be well under 100%! Not only will that percentage depend on the quality of the instruments, the measurements, and the data processing, but there are even certain physical limits that prevent it from ever reaching 100% or even from getting to a reasonable level of confidence without a certain amount of observation time. If you want to map an alien planet, for instance, you need to spend time in orbit imaging and analyzing its entire surface, if for no other reason than that you can’t observe more than a small sliver of the planet at once!
Another important point involves the physical infrastructure required to give instruments the sensitivity they would need to do all these things with high certainty. Suppose we want to alert Captain Picard to the fact that the Borg ship is charging its weapons to fire. (And, obviously, I don’t mean Borg led by a relatable megalomaniac queen; I mean terrifying faceless drone Borg coming to assimilate you.) Presumably, the phrase “charging weapons” means that the energy in some kind of battery or capacitor bank is building up. We could, theoretically, detect photons emitted from such a system. But, first of all, I would think that the Borg shield systems like that, since they value efficiency so much – so very few photons will come out for us to detect. Second, a single photon won’t be enough for us to tell what’s going on. We need enough to get a good signal-to-noise ratio: that is, we need enough photons from the Borg weapons system to confidently say that they are from an energy buildup in that weapon system, and not from anything else. If there’s a fixed number of photons coming out of the Borg weapon, then there are basically two ways to build that confidence by measuring more photons: give your sensors a long time to measure, or catch photons from a larger area. We want to give Picard a result fast, so we’d have to go for the bigger photon-capturing. Much bigger. Especially if you want to pin down the exact location of those photon emissions: angular resolution at any given wavelength of light depends directly – and only – on the telescope baseline size. Therefore, first up on the Enterprise’s battle plan should be the deployment of a giant reflector dish. I think something with a diameter of a couple hundred kilometers should suffice!
The impossibility of Sensors as we usually see them depicted could have a huge impact on many sci-fi storylines. For instance, characters should have to make decisions on much more restricted information – or spend much more time considering their actions. Our characters will also find themselves in many more situations where they can’t solve the problems we throw them up against, simply because they don’t have enough information about the problem or they have to take too long to figure things out. There are other impacts, too. For instance, I’ve seen arguments on the web that stealth spacecraft are impossible (because any spaceship with humans in it will be at a temperature much higher than ambient space, so it will emit thermal radiation). These arguments assume the existence of Sensors, and further assume that the Sensors will always trump alien thermal management schemes. And in hard sci-fi circles, particularly in computer-game universes, there is also the concept of active versus passive Sensors: active Sensors are like radar, which bounce a signal off of enemy ships (thus making your ship easier to detect); while passive Sensors are like cameras, which just collect emissions. However, though that distinction may be meaningful, it’s not practical! Unless you really want to deploy those huge detector telescopes, you had better break out the radar if you want to locate your enemies before they fire all their missiles.
#2: Orbits
When you arrive at a planet from deep space, you want to park your spaceship. The parking space is an orbit. Contrast with deep-space maneuvering, when your spaceship can go any direction it likes any time it wants.
Well, no. Not exactly. Not at all, in fact.
Orbits aren’t just for parking – they dictate everything about moving around in space. The International Space “Station” is always moving at many thousands of kilometers per hour because of orbits. Geostationary satellites are at a really high altitude – over 35,000 km – because of orbit mechanics. We only launch space probes to Mars about once every two years because of orbits. Interplanetary space probes can only reach certain destinations with the amount of fuel they carry because of orbits.
Whenever two sci-fi spaceships meet at a planet, they aren’t going to be exactly next to each other except by design. If their orbits are inclined or eccentric relative to each other, or at different altitudes, then the ships are going to be continuously moving around relative to one another. If these ships get into a space battle, then they are likewise going to be moving around each other in arcing paths. The trajectories of the arcs will change as the ships maneuver, but there is definitely going to be constant, hectic motion, and it definitely won’t all align nicely with some arbitrary 2D plane.
Nice neat flying-wedge-style formations in orbit?
The worst offender on this point, in my opinion, is Ender’s Game. One of the premises of the book is the argument that, in space, the enemy could attack you from any direction and at such speed that you cannot anticipate the attack; therefore, defense of a planet is impossible and everyone has to be on the attack all the time. This is an interesting idea, but it’s true only if the attacking spacecraft have unlimited power and propellant. In reality, those resources must be limited and so the attacking fleet is going to have to take some orbital trajectory to get from their planet to yours. Just like NASA planning the launch of a Mars rover, they’ve got to pick their launch window carefully – which means that you actually could predict which trajectories the attackers are more likely to use.
The mechanics of orbits matter to sci-fi stories: they are like the layout of highways and roads across a country. If some characters need to get from one planet to another, there are certain orbits they could use and certain orbits they could not. They determine how long the trip takes, and what subsequent destinations the characters can reach. And orbits keep ships moving with respect to one another along curving paths in all three spatial dimensions, making spacecraft behave in a manner that is completely unlike watercraft (or even aircraft), which is how we usually see them depicted.
#3: Co-opting a Current Science Word to Mean “Magic”
All of these words, even the more sciency-sounding ones, are often thrown around in sci-fi as synonyms for the word “magic.” My favorite examples come from Peter Hamilton’s Void Trilogy, when characters with all sorts of technological implants “manifest a quantum field function” in order to do things (unlock doors, tap into computers, fire lasers, etc). What the heck does this mean? Hamilton just strung together some cool-sounding words. His characters might as well be waving magic wands or using the Force. At least the Star Wars universe is honest about this!
The thing is, terms such as the ones I listed describe technologies that we have now and don’t mean at all what the sci-fi writers think they mean. For example: nanotechnology. Nanotechnology is the manufacturing capability to build things with sizes measured in nanometers, and it happens all the time in the electronics industry without giving anybody superpowers. What nanotechnology does give us is a ton of transistors on a silicon chip. Same for genetic engineering: we have been splicing genes and resequencing DNA for decades now – and cruder genetic engineering in the form of selective breeding goes all the way back to Gregor Mendel. You can thank genetic engineering for apples and insulin, but again – no mind-melding, magnetism-wielding, or time-winding powers.
I do not think that it’s inconceivable or wrong for writers to take the Arthur C. Clarke leap, and posit that sufficiently advanced technology is “indistinguishable from magic.” But in order for that to work, the technologies have to have either technical explanations that use concepts we can’t relate to our current understanding, or leave off the explanations entirely. Think of explaining that Droid phone to a Roman: it wouldn’t make sense to say, “Oh, you have aqueducts. Well, over time, aqueducts got better and smaller and eventually people built this handheld device which works by really good aqueducts.” That extrapolation of technology is misleading and incorrect. The “indistinguishable from magic” idea comes into play because the Roman doesn’t understand electrons or transistors or LCDs, and those terms are completely meaningless to him.
Often, terms like these are handled well – and science fiction is a tremendous vehicle for exploring the potential implications of emerging sciences. Where I have my biggest problem is when a story says something like, “after the introduction of nanotechnology in 2167, nanotech-enhanced human muscles, nerves, and brains entered the market.” Lines like that show that the writer just thought the word “nanotech” sounded cool and didn’t want to think very hard about how the theories or technology we have now would feed in to the technology of tomorrow. It’s a cop-out that doesn’t align well with either our current understanding or the effects the writer is trying to describe. Where those cases are concerned, I kind of like it better when we have “the Force” and “red matter” and other such things without any explanation.
Runners-Up
I decided on a top three based on those issues that I think have the biggest impact on sci-fi stories. There are, of course, a whole host of other science problems in most popular sci-fi.
The closest runner-up, in my mind, has to be designing spacecraft like ships – with planar decks stacked on top of one another, such that if you stand on the surface of a deck you can face in the direction of travel of the spaceship. There is no reason whatsoever to do that. In fact, if you’re interested in getting some artificial gravity, it makes much more sense to stack the decks vertically, so that the lowest deck is toward the engines and the thrust is always “up.” But if sci-fi starship designers want to really go nuts, they ought to start canting decks at angles, wrapping them around cylinders, or just having a string of cabins that the starship crew floats between. Written sci-fi is much better about all this than movies, TV, or games are. (Artificial gravity itself is something I’m willing to give sci-fi movies and TV shows a pass on, simply because I understand the production limitations and I’d rather see more innovative sci-fi come out of Hollywood than less. It can fall into the “magic” category. But it’s no excuse to design ship-style decks.)
Sound in space is also a science error, but I’m happy to let it slide for the sake of artistic license. Same goes for big fireball explosions. Some shows go a long way, stylistically, by muting or eliminating sound from their spacecraft, though!
Most sci-fi gets the idea of rocket engines way off. Orbit maneuvers – including getting onto a transfer orbit to another planet – require a change in velocity known as delta-vee. Delta-vee comes from firing a rocket engine. The more the engine fires, the more delta-vee the spaceship gets. Simple enough, but the problem lies in propellant consumption: a spaceship only has a finite amount of propellant aboard, and when you use it all up in engine burns, you can no longer move your spaceship around. So spacecraft rocket firings necessarily happen only during brief intervals, when absolutely necessary. A real spaceship will never have rocket engines on continuously in an “idle” state, or to overcome friction like a boat or airplane has to! (Electric propulsion, like ion engines, behaves a bit differently – those engines are almost always very low-thrust devices that have to be on for months, say, to get a space probe from the Earth to the Moon.) Worse, something like the Starship Enterprise would have to devote most of its mass to housing propellant reserves to accomplish many of the maneuvers we see. To get around this issue, many sci-fi universes include some kind of “reactionless” drive or other engine based on as-yet-unknown physics that can use the Clarke argument. I’m not sure why those engines need to have glowing backward-facing exhaust vents, though!
Orbit-to-surface-to-orbit shuttles are pretty bad. Barring some future magical physics, a single-stage-to-orbit vehicle is the holy grail of launch. It takes an enormous amount of fuel and propellant to escape the Earth’s gravity – far, far more in terms of mass than the rocket payload. Most launch concepts we can envision involve some component of the vehicle that doesn’t make it into space – whether it’s an expendable booster stage or a carrier aircraft that stays behind for reuse. Re-entry can be just as problematic, as the vehicle has to get rid of a ton of kinetic energy (to make a long story short, that’s what space capsules’ heat shields do). Shuttles can be obnoxiously necessary for crews of planet-hopping explorers, though…
Like shuttles, faster-than-light travel is tough. It’s the elephant in the room of most science fiction: writers are just dying to have it, but it cannot be accomplished by any means we currently know about. There are some theories out there that might give us FTL capabilities, but only under the most extreme and unrealizable conditions. (Things like…being inside a black hole and whatnot.) However, being able to move characters from planet to planet very quickly can make for richer storylines, more imaginative settings, and more exciting descriptions and visuals, and so it becomes a kind of necessary evil.
Addendum: Reader Nominations
A couple readers have commented on some other effects or technologies commonly depicted in science fiction that commit scientific faux pas.
Will pointed out “shields” and “force fields,” which form an impenetrable (or, at least, as penetrable as the plot requires) bubble wall around a starship. The idea of a deflector shield has its basis in scientific fact; but there is no real way to project a solid wall around your favorite spaceship that prevents matter and energy from passing through.
Jon mentioned that many movies and TV shows include “energy weapons” which produce blasts that travel slower than not only light, but also sound!
It’s interesting to re-read a book that made a huge impression on me the first time around. Some of them seem less exciting, while some hold up amazingly well upon multiple reads. (The best example I can think of for the latter case: Dune. Despite identifying the traitorous character by name on page 28, before we ever set foot on the eponymous planet, Herbert still surprised me with the betrayal…and when I re-read the book six months later, it happened again. I was getting all, “Aha! The Atreides are figuring it out! Duke Leto has a chance, maybe he’ll get away this time oh NOOOOOOOO” but I digress.)
The first time I read C. S. Friedman’s In Conquest Born, I was incredibly impressed. I immediately classed the book as one of my favorite science fiction novels. On my mental tally, it went right up there with Dune.
The novel explores the kinds of societies and personalities that might evolve in an environment of endless conflict. Two interstellar nations, the Azean Star Empire and the Braxin Holding, have been locked in a galactic-scale war for such a long time that, though the original antagonism is recorded, none of the combatants really care why the war started in the first place. The war has become a way of life for both sides, and both cultures have evolved along parallel – but mutually exclusive – courses in response to the war and to each other. The Azeans, determined to make themselves into the perfect fighting race, have started genetically engineering themselves – gunning not just for a specific “ideal” phenotype but for telepathic abilities, which the Braxins specifically abhor. The elitist Braxaná rulers of the Holding sought to preserve, by all the means at their disposal, the ancient warrior culture that first brought them to successful dominance over the other tribes of their planet; they hope that their traditions and ideals will carry them to victory in future conflicts as well. As Zatar puts the distinction between Empire and Holding: “While your people developed Civilization, we developed Man.”
In that environment, both nations accidentally produce a representative who embodies everything their culture has been evolving towards. The first half of the novel chronicles the formative years for Anzha lyu Mitethe, in Azea, and Zatar of the Braxaná. They both become renowned commanders in the Endless War. At almost the exact midpoint of the book, they meet each other in a room – and in the second half, the galactic war becomes an obsessive personal vendetta for both characters. They seek to manipulate their societies’ political and military goals towards their personal objective of destroying their counterpart.
The story is both epic and intimate, with references to more than enough planets, cultures, species, and events to establish a credible universe. Like Friedman’s other science fiction, major themes include self-discovery, the interplay of sexuality and power, and descriptions of characters and cultures that are neither fully good or evil.
Maddeningly, Conquest was Friedman’s first novel and not only did she send the manuscript to a publisher unsolicited, but that publisher accepted it.
An article appeared today on NASA.gov about the detection of “free-floating planets.” These planets may have formed around a central star, like the planets in our Solar System did, but due to some gravitational interaction during their star system’s formation the planets escaped their stars. These Jovian planets, which may outnumber stars in our galaxy, are now doomed to endlessly wander the cosmos under perpetual starry night skies.
Naturally, this notion tripped my sci-fi circuits.
This artist's conception illustrates a Jupiter-like planet alone in the dark of space, floating freely without a parent star. Image credit: NASA/JPL-Caltech
We live in an age in which new planetary systems are being discovered at an incredible rate. We are getting closer and closer to the ability to detect other Earth-like worlds around other stars. In fact, just a few days ago a study found that certain climate models of Gliese 581d (that would be potential-planet Zarmina‘s until-now-slightly-less-sexy sister) may support a liquid water cycle.
So what would it take for one of these free-flying, starless planets to be habitable?
The immediate answer that may come to you, the average person, is, “Joe, you are crazy.” But wait a moment!
All life requires is an energy input and certain chemicals, right? Well, all sorts of chemicals exist in gas planets. And there are plenty of possible energy inputs from the gas dynamics going on in their atmospheres – not to mention magnetic fields and other esoteric stuff like that that Earth life generally doesn’t incorporate into its metabolism.
But forget gas-giant balloon-life. Suppose we constrain our notion of habitability to the usual anthropocentric meaning: liquid water on a rocky surface.
In order for a rocky planet to have liquid surface water, it needs two things: heat and pressure. (Pressure so that the water doesn’t just sublimate or boil off into space, and heat so that it doesn’t freeze.) The “pressure” part we can take care of by giving our rocky world an atmosphere. However, we need a heat source – not only to keep the water from freezing, but to keep the atmosphere itself from freezing onto the planet, too. How do we get this heat source? Radioactive heating from the planet interior isn’t going to warm the surface to 273 K. Stars are all going to be too far from these planets to do any good. Emission nebulae are way too cold and rarified, even if the planet is right in the middle of them. The planet is going to pretty efficiently radiate away any heat inputs before that energy goes into heating ice to make water. (I suppose we could stick the planet right in the way of a black hole’s polar jet or some other source of hard radiation for our energy source – but then we’re back to getting really alien alien life. Fun to think about! And what happens to those alien civilizations that thrive on a dark planet bathed in X rays when their planet finishes traversing the zone of hard radiation?!)
I’m pretty convinced that liquid surface water is not going to appear on any free-flying rocky planets. Unless…
Suppose, when a Jovian planet got ejected from its birth star system, it carried its moon system away with it. Maybe some heat can come off of that gas giant and hit the moon! It’s not going to be reflected light, though, because there’s no star to provide bright enough light. No, the energy will have to come from the Jovian itself. This condition means that we’ll have to look at something like brown dwarfs: astronomical bodies that are just slightly too small to ignite under their internal pressure and turn into the hydrogen fusion furnaces that are stars. But they do have some fusion going on in their dense cores.
Take Teide 1, the first brown dwarf to have its existence confirmed. It has a surface temperature of around 2500 K, a luminosity of about 0.001 Lsun, and a radius around 0.1 Rsun. Suppose that a rocky (Earth-density) satellite orbits Teide 1 at its Roche limit, the closest orbital radius it can have without tides tearing the moon apart into a pretty but uninhabitable ring. (By a quick calculation, I get about 337,000 km for Teide 1 – coincidentally close to the Earth-Moon distance.) At that distance, the moon would receive around 1 million watts per square meter from the Jovian. If that’s the input power, the Stefan-Boltzmann law gives the output radiation of the planet in equilibrium. With a couple assumptions about albedo (Earthlike) and assuming that the moon receives incoming radiation over its cross-sectional area but radiates out over its entire surface (and that it’s the size of Earth’s Moon), my quick hand scratchings give a surface temperature near 50 K. Hmm…no liquid surface water there.
But there’s another possible heat input to a moon around a gas giant: the tides of the Jovian world.
Consider Jupiter: it has four big moons, and Jupiter raises such huge tides on these moons that the rocky mini-worlds actually flex, generating heat from friction. On Europa, this tidal heating in its central rocky part is sufficient to melt the inner bit of its water-ice coating into an ocean. Heck, scientists combing Galileo probe data just determined that tidal heating is sufficient to keep pretty much all of Io’s interior molten. That world is made of lava, with a thin crusty shell. And it’s all because the moon orbits a gas giant in a resonance with some other moons. the interaction between their orbits keeps the tidal energy coming.
So let’s give our moon some companions and an orbital resonance. Solar radiation is negligible compared to tidal heating even for Jupiter, so we know that that could give our moon liquid water…at least under the surface, like Europa.
But add an atmosphere, and you get an insulating blanket around the moon’s surface. More internal heat stays trapped on the moon’s surface instead of radiating away into space. I haven’t done the calculations, but if tidal heating can liquify rock on Io I bet it could be enough to melt Europa’s ice layer all the way through for slightly different orbital parameters. And with an atmosphere, the moon gets pressure to keep that liquid water from boiling. Like Titan. Put Titan where Io is…and what do you get? I’m not sure, but it would be really interesting. And it wouldn’t require the Sun.
Cool, huh? It certainly hasn’t been confirmed, and I don’t have a detailed model, of course, but I think the theoretical grounds exist for these free-flying dark planets to have liquid-water surfaces. Imagine vacationing on a beach next to a steaming ocean that is basically a global-scale hot spring, where it’s perpetual night and every couple (Earth) days you see the shadowy form of the gas giant loom overhead, visible more because of the stars it blocks out than from any external light source, except for the occasional immense spark of lightning through its clouds…
A friend who – allegedly – hates puns inadvertently reminded me that I let Star Wars day go by uncelebrated on May the 4th (be with you). Fortunately, last week I also got into a discussion with some of my new coworkers in which that classic get-to-know-people question came up: if you had three wishes, what would they be?
My first two are no-brainers. For me, at least. One: no more diabetes.
Two: Millennium Falcon.
She's the fastest hunk of junk in the Galaxy. She may not look like much, but she's got it where it counts.
I think having the Millennium Falcon at my disposal would actually keep me pretty much set without spending the third wish. Just think of all the problems I could solve if I had the Falcon!
It’s a mobile home. It’s fast transportation. It’s a thrill ride. It’s a utility vehicle. It comes with built-in security systems. I could have fame and fortune or solitude as I desire. It has little dangling masks that let people breathe in space. It’s got extremely capable long-range scanners. It has a landing claw that lets it stick to Star Destroyers.
Problem: Only twelve humans have ever set foot on another planet, and I am not one of them. Solution: She’ll make point-five past lightspeed!
Problem: I have never been to Barbados. Solution: The Falcon flies just as well in atmosphere as in space! And I don’t have to book a hotel, either!
Problem: people are nosy. Solution: pop-out blaster turrets!
Problem: my hand fell off. Solution: Stick my arm in this tube in the medical bay!
Problem: I keep losing my Lando Calrissian. Solution: the Falconcomes with clips!
Problem: NASA moves too slowly/has no money. Solution: Heck, I’d take planetary scientists to other worlds for ten bucks.
Just about the only thing it can’t do is escape a tractor beam.
...so I won't get too close to any small moons. Just in case.
One of the fun things about grad school in science or engineering is getting a bunch of highly technically educated people together to go see a movie. Like “Battle: Los Angeles.” If you want to see a movie with Marines being very Marine-y and some big gasoline explosions, go see this movie. If you want to see cool aliens, awesome technology, and innovative ideas, then, uh…don’t.
You will see a lot of guys hooah-ing and a lot of wreckage.
I’m not going to do a general review of “Battle: LA,” nor a general critique of the science. (I will leave the latter up to Ryan, and I’m sure if he does such a critique it will be a fantastic read.) I will say that I liked how the aliens basically use guns and jets/rockets instead of inexplicable hover-things and energy blasters, and I liked that the reason the aliens are unstoppable at first is not because of their tech but because our soldiers don’t understand how to fight them. (Of course, the usual video-game rules of technology apply: three bazillion M-16 rounds fired into an alien aren’t enough to kill it; but do one quick alien autopsy in the field and suddenly all our guns work with full effectiveness!)
It’s the premise of the movie I want to poke at. The whole reason the aliens are attacking Earth is to claim our resources. Sound familiar? In a brief glimpse of a TV news program, Professor Greybeard explains (scientists, get your cringes ready!):
The aliens must be attacking us for our resources. Specifically, our water. 70% of Earth’s surface is covered with water, and the chemical composition of our water is unique in the solar system: it is in liquid form.
(I paraphrased from what I could recall.)
This is both factually inaccurate and a ridiculous premise for an alien invasion, for three reasons:
The Earth’s water has exactly the same chemical composition as water anywhere else in the Solar System: two hydrogens stuck to an oxygen. And, in fact, water is one of the most common molecules in the Solar System – nay, universe!
The Earth is not the only place in the Solar System where liquid water exists: scientists are about as sure as scientists can be that there is liquid water under the crusts of Europa and Enceladus, and possibly Ganymede and Titan as well.
Water (liquid or ice) is available in many places throughout the Solar System, and as it turns out, the water on Earth’s surface is one of the hardest places to get at it, if your starting point is space.
Now, I will have to explain #3 a bit. My point relates to the depth of the Earth’s gravity well: in the words of xkcd, the reason “why it took a huge rocket to get to the Moon but only a small one to get back.” If aliens wanted to take our resources, presumably they want to do so because they need those resources for something. And since this alien civilization apparently makes a living moving from planet to planet (or star system to star system), they are going to have to move these resources or their products off of the planets they were harvested from. That means, for every kilogram of water the aliens pump out of Earth’s oceans, they need to produce spacecraft, rockets, and fuel to get the water up into space again. Think of how big the Space Shuttle is, and how much fuel we load it full of, just to get school-bus-sized Space Station modules into orbit. Contrast that with the tiny Lunar Module ascent rocket from the Apollo days.
Clearly, there must be a better way to get water off of planets. So, without further ado, the Quantum Rocketry Guide for Successful Star System Invasion and Resource Extraction for Nomadic Species: Continue reading Quantum Rocketry Guide: Star System Invasion!→
Don’t watch the first or last seasons. Also don’t watch the season 4 finale.
Battlestar Galactica
When they escape from the planet at the beginning of the third season, HUMANS WIN. End of show.
Doctor Who
It’s supposed to be cheesy, but whenever you see something so stupidly cheesy that it totally rips apart suspension of disbelief (e.g. main characters getting abducted onto 2000s reality TV shows, ’60s robots chanting “DELETE DELETE DELETE,” etc), hold “fast forward” until it looks like something serious is happening.
Farscape
Put up with the first season until it gets under your skin. John Crichton is just as confused as you are. 4th season is optional.
Firefly
Fortunately, it got cancelled before it had a chance to go bad! Movie very optional.
Futurama
Watch it all a zillion times.
Star Trek: The Next Generation
Pay attention after Riker grows a beard. (This is a well-known effect.)
