The Biggest Science Errors in (hard) Sci-Fi

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”

Nanotechnology. Genetic engineering. Biotechnology. Mutation. Cybernetics.

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.


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!

28 thoughts on “The Biggest Science Errors in (hard) Sci-Fi”

  1. “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%!”
    You seem to ignore the fact that sci-fi functions on technology beyond our own and in some cases beyond our reasoning. Startrek has “tachyons”, faster than light “particles”. It is possible to reduce or even potentially eliminate any significant error bu conducting multiple “scans” using different technologies. Each scan would/could produce errors but it is unlikely that a different scan technology would produce the same error.
    “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!”
    Again you assume our technology. Suppose a technology that is able to emit a beam of “whatever” and define its energy so it cannot penetrate solid matter or it can penetrate but to a defined depth. By running multiple scans at differing energies, you could get a 3D image of an object from a single perspective.
    “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”

    Wow you are naive! First the borg shields do not stop photons in any quantity or you would not be able to “see” it. Who said the energy charge is photons? when we “charge” an electrical discharge weapon there are no photons involved as is the case in charging capacitors to power a laser.
    “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.”
    The reason for the orbital paths to distant objects is not because of physics but rather because of cost. We can “fly” direct to Mars or any other item in space if we can expend the energy required to do this. In chemical propulsion the cost to list the extra fuel is unjustifiable for most missions. We can and do fly freely in space. We do it to get into “orbits” by adjusting trajectories.
    “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. ”
    Ships with sufficient “energy” do not need to orbit, an orbit is a stable position where no further energy is required to be expended to maintain course. A ship powered by “antimatter” could easily have sufficient energy to hold or change its position relative to almost any other object in space (singularities excluded).
    “Nanotechnology. Genetic engineering. Telepathy. Psionics. Biotechnology. Mutation. Cybernetics.”
    5 out of 7 of your magic words exist in today’s technological world as fact, to varying degrees.
    “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.”
    There is more reason than you think! Astronauts get a lot of training in spacial orientation, why? because we throw them into an alien environment (zero G space) and expect them to function normally. A spaceship that mimics your natural environment is conducive to familiarity and hence functionality.
    “a spaceship only has a finite amount of propellant aboard, and when you use it all up in engine burns”
    Matter and energy are the same thing in different states therefore, if a spaceship with advanced technology were to have an abundance of energy, why can it not “manufacture” fuel? There is no antimatter in the Cern cyclotron, but after you power it up we can make it.
    “some theories out there that might give us FTL capabilities, but only under the most extreme and unrealizable conditions.”
    Do some reading on Quantum teleportation. This is instantaneous travel … any distance and it exists today. We have a great deal of knowledge about our universe, and we are moments away from mastering it. NOT! if our universe were the volume of information, we know the volume of a pea and we are the age of the universe away from mastering it.

  2. I think your issues with much of modern sci-fi is related to only thinking in current terms. If 500 years ago someone tried to describe today’s technology, your counterpart could file the same protestations because he/she would be looking at it through the current terms of that time.

    Unless the sci-fi story makes an error that is clearly wrong – like a planet without gravity for example – then I think we should follow the premise put forth by the poet and philosopher Samuel Taylor Coleridge, who suggested that if a writer could infuse a “human interest and a semblance of truth” into a fantastic tale, the reader would suspend judgment concerning the implausibility of the narrative. His premise is often boiled down to just having “a willing suspension of disbelief”.

    If we are really considering a story that takes place hundreds of years from now, then we should allow for the distinct possibility that there have been discoveries between now and then that completely change what we currently hold to be sacred. If we can’t do that then we should stick to non-fiction.

  3. Louis–

    You bring up some good points. You are certainly correct that I am working from the assumption that our current understanding of physics remains valid! I do this for two simple, practical reasons: first, that is our current understanding of physics; second, it is very difficult, if not impossible, to predict the kind of new physics required to give us these technologies. I imagine it would be similar to trying to predict quantum mechanics or relativity in 1890.

    Now, let me address your concerns point by point:

    You are correct that multiple types of sensors, producing different kinds of information, can be combined to produce a better picture of whatever it is they are sensing. (In research circles, this is called “sensor fusion.”) However, that kind of processing can only reduce errors – it cannot eliminate them completely. They might be very small, but they will still be there; and the further away and better-shielded an alien ship is, the worse the errors will be.

    The planet-scanning “beam of whatever” you propose would have to be something that doesn’t obey any of our current physical laws. Let’s say you want to use something that does obey our understanding of physics to map a planet from low orbit: something like neutrinos or outstandingly high-energy gamma rays, which would pass through most matter but, sometimes, interact and scatter. We could measure any part of the beam that scatters back to us, and build up a picture of where the planet is more or less dense. The problem is that you get back to the need to resolve lots of photons or particles scattered intermittently, and in order to pick up those scatterings, you need a giant dish. The concepts of telescope sensitivity and angular resolution come from the geometry of the situation – they aren’t specific to visible photos.

    When I said that the Borg “shield” systems like their weapons, I didn’t necessarily mean the bubble-shaped Shield you see around Star Trek ships, absorbing enemy weapons fire. I simply meant something like encasing their weapons capacitors in metal sheaths, which would have the effect of blocking most of the photons emitted from the capacitors (and incidentally making them more safe to handle for all the Borg drones in the area). You see, if you have a taser (an electrical discharge weapon) and you charge up its capacitor, what the device is doing is pushing a bunch of electrons from one side of the capacitor to the other, ready to spring across and discharge. Electrons have an associated electric field, and whenever electrons move, the field outside the device changes – and a changing electric field produces photons! They are not visible light photons – they are most likely radio photons – but they could be measurable. If you have a big enough dish to measure them effectively. And if the Borg shields don’t block that radio wavelength.

    You are exactly correct that economics factors into the equation, and is often why NASA chooses the trajectories it does. However, physics definitely comes into play in a massive way – literally! The more orbit maneuvers you want to do, the more propellant you need, and very quickly, you end up talking about more mass of propellant than the mass of your spacecraft! This was the case for the Apollo lunar missions, for example: they used the upper stage of a Saturn rocket to break Earth orbit and get onto an orbit that traveled to the Moon, and there was more mass of propellant in that Saturn upper stage than the mass of the Apollo Command, Service, and Lunar modules! So, while I agree with you in principle that the more fuel you put on a spacecraft, the less you have to stay in a free orbit…you would need a prohibitive amount of propellant.

    You will run into the same problem with antimatter. When matter touches antimatter, both turn into high-energy gamma photons. Assuming that all the photons go out the back of the rocket at the speed of light, you can calculate (Google “rocket equation”) the mass of matter and antimatter required to produce a certain delta-vee. I recall calculating that when Captain Picard says “all stop” while travelling at warp 0.5, he would need to expend several times the mass of the Enterprise worth of antimatter.

    “5 out of 7 of your magic words exist in today’s technological world as fact, to varying degrees.”
    Exactly my point! Sci-fi authors appropriate words they see as “cool,” but then ascribe “magical” properties to those words that are usually not associated with the actual meanings of the words. That’s my point!

    Astronauts on the ISS do tend to align themselves with a “floor” and “ceiling.” Text labels applied inside the Space Station similarly have a preferred orientation. You are correct that this is to help the astronauts orient themselves. I don’t see any problem with sci-fi spaceships using similar conventions – but it makes much more sense to me as a spacecraft engineer to stack the decks “vertically” or to wrap them in a cylinder around the central core of the starship. And once our descendants adapt to living in space, I see no reason to favor our own perceptions over theirs!

    Aha – you are right E = mc^2 works both ways! The question is whether it makes more sense to generate enough energy on a spacecraft to power a particle accelerator, or to pack the propellant from the get-go. I think the answer is the latter, because even pointing the LHC out the back of your spaceship would only give it ion-engine-scale thrust, and at the cost of generating huge amounts of power (which you would probably have to do by matter/antimatter annihilation, anyway – and now we’re back to the rocket equation problem).

    I don’t think “quantum teleportation” means what you think it means. It can transfer a quantum state, but not the physical particles – as such, it can be useful for encryption and data transmission, but not transport.

    Thanks for reading and thinking!

  4. Nelson–

    I suppose I should have said that these are my top science errors in hard sci-fi, which strives to use and extrapolate scientific concepts. Star Trek is kind of on a blurry line between “hard” and “soft” SF, but I pick on it here because of its most famous feature – the technobabble, which implies plausible technical explanations!

    I have no similar problems with “the Force” or “red matter” because those things clearly have “indistinguishable from magic” qualities. There’s nothing we have now that lets us extrapolate forward to get to those items – just like my Roman can’t get from aqueducts to cell phones. And I have no problem with literary devices, or cool ideas for the sake of putting characters in interesting situations!

    Thanks for reading and thinking!

  5. A theoretical space craft powered by the best “Electric” drive we have now still only produces exhaust velocities in the hundreds to about 1000kms/sec. If the exhaust velocities were accelerated to near light speed this would significantly increase the thrust. As the velocity of the emitted particles approached light speed their mass increases relativistically.
    Assuming the craft is powered by a matter/antimatter power system which can potentially generate 10^9 times or more the power of an equivalent mass of H2 we then attain a of very small amount of Ship mass being required for power and propulsion. I have briefly researched accelerating chemical rocket exhaust via particle acceleration techniques that would improve their performance significantly. I was looking into Traveling-wave amplification of the rocket exhaust.

    Quantum teleportation is indeed as you clarify but if such a feat is possible today with our limited understanding and capabilities, it is not unreasonable to think that faster than light may be possible. We are barely out of the womb in our understanding and ability to use the potential that exists in our universe. When will the next breakthrough happen that will rival Relativity and Quantum physics happen, who knows but I am certain it will make a lot of our assumptions of today naive. We have discovered and applied more knowledge in the last 50years than in all of history before that.

    BTW, I tried to post some comments to your “My Space Program” but was not able. I agree with some of what you say there, and I am the founder of a project that hopes to build a space habitat … soon.

  6. As far as star trek there are “theoretical” manuals as to how and why some things “work”. Star ships are dish Ed like regular ships because they are designed to enter atmospheres with gravity, and such

  7. Guys, have any of you seen Google Earth and what satellites do to map our planet today? X-ray, ultrasound, carbon dating anyone? That alone will be enough to get readings on an alien planet if installed in an FTL starship – but something tells me the technology might actually advance a bit further and serve us with a customized portable scanner or a planetary beamer of some kind, based on the same principle that is available today. Think outside the box 😉

  8. Camilla
    “Google Earth and what satellites do to map our planet today? X-ray, ultrasound, carbon dating anyone?”

    The things our satellites do take time and multiple passes over the entire surface of the Earth to achieve. Joseph was concerned about the instantaneous assimilation of data from a single perspective “snapshot” of an unknown planet. This we cannot do … even the mighty Google!

    Think outside the box 😉 …. Me Too!

  9. Sure, Lous. But, if in sci fi we’d be sticking to things we cannot do today – there’d be no sci fi. Instantaneous assimilation of data – think about computers of the year, say, 1960… a room for a computer. Think what a computer does today and how much room it takes… I am confident future data processing devices will be able to handle information streams by far faster and more effective than what we have today. Provided humanity won’t fall into a dystopia that is…

    Anyhow, if you were to talk about errors in science fiction – don’t think mechanical things or technology – because it’s all work in progress. I mean, come on, NASA already understands how warp works – all we need is energy and material resources to make it happen.

    Errors in knowledge of the already known to us Universe – that might be something to fish for. But again, in today’s world even Pluto has been disqualified…

    I guess what I am trying to say, keep an open mind when it comes to science fiction – keep yourself entertained by projecting possibilities – however crazy and unthinkable – onto our potential, of the humanity as a whole. Science fiction is no place for a debate over technicalities – it’s a place to share dreams. The best place there is!

    Happy New Year!

    Kind regards,


  10. Camilla

    I think you misunderstood me! I am a firm believer in the science of sci-fi. In fact I have a treatment for a sci-fi movie I want to make (I need a script writer) I even have a film production company I consult with. I was just commenting on the dissimilar circumstance in the Star Trek scanners vs. Google Earth. I strongly believe we will develop much of what humans can imagine.

    If you check out my web site you will see that I am very open to “outside the box” and the tantalizing of the human imagination.

    I must read your books some time soon. You intrigue me by your comments here 🙂

  11. Appreciate that a “top 3” list is tough because it would be easier to create a top 20 list.
    “Deflector shields” or “force fields” deserve to be a runner up. Simply put, there’s nothing in physics to suggest a means to block both electromagnetic energy & matter. It’s an example of techno-babble as a solution to the difficulty of defense against known means of attack such as nuclear weapons & asteroid bombardment.

  12. Camilla–

    In fact, satellite data about the Earth (or other planetary bodies) goes way beyond what you see on Google Earth! There are images of the Earth in infrared, radar, and even maps of the Earth’s gravity field, showing where the mass of the Earth is concentrated! It’s certainly not out of the question that all this information could be gathered by a single orbiting starship, nor is it out of the question that these images could be obtained at high enough resolution to draw some of the conclusions shown on “Star Trek.” (I’m not convinced we will ever be able to assess the state of health of an alien lifeform from orbit, though.) The issue is that this data takes time to acquire, and attaining sufficient angular resolution and sensitivity requires a very large aperture sensor. Again, I don’t contend that such a thing is impossible – unless it gets to the point of violating Heisenberg’s uncertainty principle – just that its presence would dramatically change most sci-fi plots. The Enterprise should take many orbits over a planet to map it, and it should take time to deploy and retract the necessary huge sensors (note that the paired satellites of the GRACE mission fly over 200 km apart).

    I don’t necessarily agree that if we restrict ourselves only to the technologies available today, there would be no sci-fi. Many successful hard sci-fi authors have done exactly that – either exploring how a particular innovation might impact society, or describing technologies and capabilities that are not new but rather are optimizations of things we have today (Robert Forward comes to my mind).


    I’m curious about what you mean by “traveling-wave amplification of rocket exhaust.” Do you have any papers you could point me towards?


    How could I have forgotten deflector shields and force fields! These are ubiquitous in sci-fi, and you are right that we don’t have knowledge of physical principles that could produce such a bubble shield or “force field” wall. There is a grain of truth to the idea of deflector shields, though, in that a magnetic field can divert radiation and charged particles to, for example, protect astronauts outside the Earth’s atmosphere and magnetosphere. And there is a grain of truth to the idea of a force field, though in physics the term means the class of concepts including things like gravitational fields, not an invisible, powered “wall.”

  13. All–

    I am thrilled that I’ve provoked such a discussion!

    I think that science fiction has many purposes. Certainly, chief among them is unshackling our imaginations to develop ideas about technology, society, and people in the future. There is a lot to be said for “soft” sci-fi – the subgenre that doesn’t concern itself with grounding all its science-based concepts in known fact, but in simply imagining what might be.

    “Hard” sci-fi, which tries to do more extrapolation or imagine technologies and concepts that could work in our physical universe, is a bit of a different beast simply because physics, chemistry, geometry, and other branches of physical law that govern the workings of the universe all place limits on what is possible – at least in terms of science and technology. I like this branch of sci-fi because it generally describes ideas that could work, according to our current understanding of the universe.

    Our “current understanding of the universe” is certainly incomplete, and may undergo some sort of revolutionary changes. A statement attributed to Lord Kelvin around 1900 famously pronounced that there was “nothing new to be discovered in physics” by that time; only five years later Einstein published his special theory of relativity and the quantum mechanical revolution took place within the following few decades. Prediction of such scientific revolutions is notoriously difficult, and prediction of what the new theories might involve is impossible. So, it is conceivable that we will discover some new theory that allows faster-than-light travel, instantaneous high-resolution measurement that would violate the uncertainty principle or the geometry of telescopic resolution, and other “soft” sci-fi devices.

    The thing is: our current understanding of the universe is the best picture we have for how the universe works. We can use our imaginations to optimize current technologies a great deal (explaining, for instance, the evolution of a computer from a room-sized contraption to a handheld device) but there are some limits to what is possible. Unless we discover some fundamentally new physics – and although I happily admit the possibility of that event happening, its presence firmly divides “hard” sci-fi from “soft,” and that new physics could not be related to concepts that we know about today. Put another way: Star Trek’s “subspace” is more plausible to me than anything in that universe that includes the word “quantum.”

    Even things that are possible might be completely impractical to any society that we might conceive. Statements such as, “ships with sufficient ‘energy’ do not need to orbit” and “NASA already understands how warp works – all we need is energy and material resources to make it happen” are correct in that such things are possible, but the qualifiers like “sufficient energy” are where we encounter problems. If the Starship Enterpise is to last a single episode without orbiting, it will have to haul around gargantuan masses of matter and antimatter to feed into its warp core; by “gargantuan” I mean the masses of several planets. Similarly, “sufficient energy” to go to warp, according to NASA’s current understanding, might involve consuming the equivalent energy of many star systems (or, perhaps, galaxies) every time you want to engage your warp drive. Not only is it unlikely that a single starship could carry around those kinds of resources (especially if it also wants to ignore orbit mechanics), but a whole society based on such starships would rapidly run out of fuel – not to mention being inherently xenocidal in the process.

    Of course, none of this is to say that a science fiction author can’t decide to throw out the laws of physics in order to serve the plot!

  14. Louis and Joseph, thank you very much for the conversation! Lots of good thoughts, that’s pretty awesome.
    Lous, i’ll be reading your website 🙂
    Kind regards,

  15. Great article. I am surprised you did not mention energy weapons traveling at sub-sonic speeds and that make noise.

    With the space ship maneuvering and planet to space flight – if you are giving them artificial gravity the you also must give them the ability to manipulate gravity. There are some huge ramifications to that. You can easily shying if you can nullify its gravity. Same with all the ships in space. This also may help explain FTL travel ?negative gravity? Then we have to assume these shields could protect the ships from e massive amounts of radiation you would be exposed to traveling at close to luminal speeds say ~600ft thick lead lining.

  16. Read Michio Kaku “physics of the impossible” some interesting opinions on Sci-fi science. I don’t agree with him completely but still a good read.

  17. Just wanted to make a small point that I think might recap what John said. In #2 “hard” sci fi definitely had grounding for orbit-surface-orbit shuttles. Assuming artificial gravity is actually artificial gravity and not something like magnetic plating, then the civilization has control of the Graviton, the particle that gives gravity its properties (much like the photon and light). If they can leverage that technology to make artificial gravity then it is certainly plausible that they can use it to reduce the force of gravity on a shuttle (a lot like eezo from the mass effect series).

  18. I’m not sure about that. Shooting gravitons at an object might attract it towards you, but I don’t think you could generate a repulsive force.

  19. Shuttles are actually quite reasonable. While getting 10 km/s in with no staging seems difficult today, the technology is already on the verge of practicality, with the Skylon craft predicted to carry 15 tonnes of extra payload. Certainly, any interstellar starship has thousands of times that much delta V per stage, and three key changes in propulsion tech would make SSTO trivial.
    1. Low weight hybrid turbo/ram/scramjets.
    2. Hybrid rocket/jets
    3. Nuclear thermal propulsion.

    All of those are virtually guaranteed in ANY sci-fi setting, so SSTOs should be as practical for them as powered flight is for us. I mean, if you have a setting in 2140, that’s about a century past the era where SSTOs are expected to dominate space launches.

    What’s less realistic, I think, is how cheap their cargo generally is. I mean, a massive starship would be expensive. The cheap way involves packing in thousands of nuclear bombs as fuel. Ambassadors, etc, would not have private interstellar starships, and freighters would not be something that’s just part of the family business any more than airliners are. Furthermore, whilst an airliner can take out a skyscraper and kill a thousand people, a nuclear-powered starship can take out a metropolitan area and kill millions. For example, an weak interplanetary freighter with 100 km/s of delta-v and a dry mass of 10000 tonnes could achieve a kinetic energy of 50 petajoules, about the same as a 12-Megatonne bomb. A similarly sized interstellar freighter with 100000 km/s of delta-v could obtain a kinetic energy of 50 zettzettajoules, or 5*10^22 joules. That’s roughly equivalent to all of the fossil fuel in the entire world, and furthermore, it’s 10% the energy of the asteroid that killed off the dinosaurs. You’re not gonna have governments just letting people do whatever they want when they have starships capable of destroying cities and even civilizations. Even so much as a 30-ton dry mass space taxi with an impact speed of 30 km/s is going to have 13.5 Terajoules, about the same as a 3-kilotonne bomb and capable of striking anywhere in the world and taking out a any civilian or military target. If we’re worried about North Korea and Iran having this sort of weapon, what do you think or reaction would be if someone proposed we give it to every greyhound bus driver?

  20. The other thing that bugs me is the idea of generic fighter craft. The operational requirements are vastly different in deep space than in orbit, and vastly different in orbit than in a planetary atmosphere. Furthermore, they are vastly different in a planetary atmosphere than above low-gravity atmosphereless worlds, and many engine technologies rely on the atmosphere being of a particular density, composition, and even temperature. Additionally, gravity and landing requirements vary drastically, with horizontal landing being important on Earth, but nearly impossible on the moon. let’s look at two somewhat similar worlds, Titan and Earth. Let’s say we send a fighter plane designed for Earth to Titan? It would have no thrust unless it ran on a completely different fuel on Titan or had its own oxidizer, as burning hydrocarbons with nitrogen isn’t possible. Furthermore, the air density near the ground would make its gun highly ineffective. It would also probably get frozen, and has way bigger engines than it needs.

    Similarly, brining a fighter from Venus to Mars would likely result in explosions, as a Venus fighter is meant to hang from a carrier blimp and use a prop or something to maneuver and would need to be as sleek as possible just to get moving quickly, whereas a Martian fighter needs to deal with flying at constantly supersonic speeds using a bypass rocket or nuclear jet, and needs big wings just to stay aloft without melting due to sheer speed. A fighter on the moon would live in the transition between hover and orbit with a reasonably-sized rocket, and would use thrust vectoring, beefy RCS and/or massive reaction wheels to quickly point the rocket where it needs to accelerate from. Above all, it would be mostly rocket fuel as to prolong its short flight time. It would be designed to either dock with an orbiting spacecraft, wait in lunar orbit, or land vertically with the main engine. A fighter built for orbit would be a mix of thrust and efficiency, meant to gun the rockets for evasive maneuvers While applying thrust to maneuver it’s orbit for tactical supremacy. A deep space fighter would be designed to operate in a small constellation with several allies in order to mitigate the enemies ability to hide behind forward armor plating. In particular, kinetic missiles are likely to instantly scrag starships, but are easily dodged if their guidance system can be taken out with a laser or other beam weapon, so laser-armed fighters could work in groups to prevent each other from needing to burn through extremely thick kinetic missile front ends to kill the squishy guidance systems behind them and deliver their own deadly kinetic payload.

    All of these craft would be of very different size, mass, shape, configuration, armament and cost cost. A 500-tonne tungsten-coated laser and kinetic deep space fighter will drop like a rock on Mars, fail to cause damage or dodge in orbit, heat up in Earth’s, Titan’s or Venus’s atmospheres until it crashes into the ground, etc. All this points to the idea of a Swiss army space fighter being silly, as there are really at least 4 entirely different combat regimes, each of which is further nuanced by the planet itself. Also, there is more than 1 kind of atmospheric fighter, from helicopter gunships to tough and maneuverabile attack craft to supersonic energy fighters to hypersonic fighters at the edge of space. Really, it might be worth redesigning, or at least heavily modifying, your fighters for every planet they go to, and having 3-6 completely unique types that don’t share anything in common beyond screw sizes. Even the cockpit chair will be different due to different accelerations, the need, or lack thereof, to be frugal about weight and space and period of use.

  21. I’m just wondering in what galaxy Star Trek is considered hard sci-fi. It’s space opera with a very thin veneer of science. That they make an effort to look more hard sci than Star Wars doesn’t make Star Trek any less fantasy than that franchise. Likewise, the necessities of a network television series– fairly low-budget and with an antagonistic studio in the case of TOS– have to be taken into account. Ignoring them means you aren’t actually taking everything into account. Can’t really have a realistic timeframe for sensors and the like when you have to quickly move passed exposition in order to get to the heart of the episode. Transporter technology itself exists entirely because they didn’t have the budget or time to film planet landings every episode. Everything about the science in Star Trek and other sci fi television is a result of the necessities of the medium.

    1. @Nikos Carcosa

      Ha! Fair. Star Trek certainly isn’t hard sci-fi – it’s just easy for me to pick on as an admonishment to future hard sci-fi writers: don’t ever write “sensors detected a life form!”

  22. The author of the article has a point about sensors, but then goes into just as much gobbledygook as he complains about in his utter failure to comprehend sensors.

    His comments on Orbits exhibit a good bit of ignorance, as well. An orbit only applies when you are gravitationally bound to the object being orbited. Perhaps the author should do himself a favor and delete the entry.

    1. @akaramis

      I apologize that my description of sensors as noisy and incomplete measurement sources seemed like gobbledygook. I will try to do a better job communicating in the future.

      However, I don’t see any factual errors in my statements about orbits. While it’s true that orbits “only” apply to a spacecraft when it is gravitationally interacting (not just bound! We must take care to include hyperbolic orbits) to an object, practicing spacecraft engineers like myself always treat spacecraft trajectories with a central body. Even interplanetary probes are orbiting the Sun, and neglecting this fact will lead to major errors in trajectory design. For the image I show in the post, with a planet clearly visible, the starships must be in low- to middle-range orbits that are certainly gravitationally interacting with the planet.

      From your comment, you seem to have a strong opinion that I have factual errors in my discussion of orbits. If there are specific items, I would like to hear which so I can correct them.

  23. I love warships whose command centers have big beautiful exterior windows. Bonus points for characters with keen eyesight who outperform mil-spec sensors and spot the enemies using their Eyeball Mk1s.

    Don’t really agree with your point about Orbits. Most sci-fi ships use either reactionless drives of some sort, or at the very least ridiculously powerful torches. So spending a few km/s delta v to come at the enemy from an unforeseen angle is probably not a big deal.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.