Hello science fiction fans! Welcome to another Science Fiction Problems! This week we’ll be discussing another big thing
in sci-fi books and movies (especially movies), holograms! As one of the more widely used fictional technologies, most people are familiar with holograms. The Holodeck on Star Trek is a more familiar example, where the characters enter a room and the computer (usually at their command) builds the rooms and people around them, creating a visibly real environment. Today I’ll be taking a look at some of the problems we currently have with the technology, and how it might be reasonably done both in real life and in your story.
Hologram, My Foot! That’s “Hard Light”!
I know I’ve picked on Star Trek a lot through these posts, but in reality, a lot of the technological ideas in the show, good and bad, gain public popularity and shape the impressions many people have about what is mechanically possible. This happens with other sources, of course, but Star Trek’s a heavy-hitter in this area. One of the things from the show I always really (really) wanted to see in real life was the holodeck- being able to go into a room and do whatever you wanted, limited only by your imagination and the computer’s ability to replicate sounded pretty cool to me. Unfortunately, as I discovered on further examination, the technology is far more fantasy than science.
You may recall from the show that characters can interact with objects and characters within the holodeck as if they were solid, real-world objects. This actually means that the holodeck is not a hologram at all, but something called “Hard Light”, a concept more at home in comic books than science fiction. A hologram is a 3-dimensional projection of an image into space, usually meant as an illusion or simulation of a real world object. It is, however, by definition not solid. So, the
holodeck’s holograms aren’t really holograms at all, they’re “hard light constructs”, that is, projections of objects that are somehow made solid.
The distinction is important because holograms are technically possible, whereas hard light is not. Right now, projecting into thin air is impossible, but we only have to figure out how to project onto empty space (or what looks like it), and we’ll have our holograms. However, nothing can make those holograms solid, making hard light possible. Obviously, we can’t just make light ‘hard’, as the name suggests, so in order to get the effect or something like it, we need to figure out how to make holograms feel real.
Haptic Interfaces: Making the Unreal Feel Real
So, you can project a 3D image, but you can’t make it solid- so what’s the next best thing? Making it feel like it is, of course! Haptic technology is the application of forces such as vibration or pressure to the human body in order to simulate touch sensation. You may have a cell phone with a touch screen which features haptics- the simplest being a small vibration created to simulate button presses. The problem with this method is that it is difficult to make the vibrations specific enough so that they are associated with the button, and it’s impossible to simulate textures. This technology is quickly being replaced, however, as electro-vibration has come on the scene.
Finally, a Use for the Obligatory Jumpsuit
While using a surface for haptic feedback would defeat the purpose of holograms, it would be possible to create a glove or even a full-body suit that would accomplish the same task on a larger scale. Using a similar electrical method (further developed along those lines), the technology could even incorporate electrical shocks to simulate wounds, as this company has done for knife cuts and bullets. By synchronizing such a suit to the computer projecting the holograms, the system could give the illusion of texture to their shapes. They would still not be solid, but it’s the next best thing, and it’s far more reasonable than ignoring the problem entirely and settling for “hard light”.
Well, that’s all for this week. Next week, I’ll be talking covering a new topic, so stay tuned! Until then, how would you make the holograms solid, to create the ‘hard light’ effect? How have you seen this handled in your science fiction? Let me know in the comments below!
While We're Paused... 
I suppose the Enterprise computer could combine holographic projection with replicator technology–but it clearly doesn’t, because replicated objects can actually exist in the real world outside the holodeck, while holodeck projected objects cannot. Curious.
There is one flaw in this post that is critical to it’s nature: the prediction of future technological developments (and in many ways the limits of physical sciences) is difficult if not impossible to predict. To understand this in a more practical nature, look at thesci-fi of the pre- and early computer age vs the sci-fi of the more modern computer age. In The Jetsons, Star Trek, and Star Wars, there is massive power represented by technology: phasers, lasers, force fields, faster-than-light drives, engines that can move entire planets (or Not A Small Moon), etc., yet the total memory of the Enterprise in The Next Generation is a whopping 1 terrabyte… which I can buy at a store today for about $100 and is the size of a large hardback book. In the beginning of the last century, we saw a massive revolution in power, with developments in electricity, internal combustion, and even nuclear power. Science fiction then predicted that to continue, resulting in flying cars and interplanatary commerce by the year 2000. Instead, after a certain point, we shifted to an information refolution. Today, the rate of information transfer outpaces anything people could even imagine 20 years ago, memory storage is what was predicted for centuries in the future, and miniaturization is already approaching the nano-scopic scale (the subject of another good post). Our energy technology has only advanced a little since then, but our information technology and miniaturization have sky-rocketed. Who knows what direction our technology will take next, and what possibilities science will uncover. Not too long ago, any decent cosmologist KNEW that the universe was static and unchanging. Chemists KNEW that the atom was completely indivisible, and the idea that matter could emit energy that may damage tissue or cause mutation in growth was preposterous. Now, we know better. Who knows that we may know in 50 or 100 years. “Hard Light” may well be achievable. We’re already managed to stop light (through the use of a material which, under special conditions, has a light speed of 0). Maybe keeping it in a holding-pattern and manifesting a solid surface for it isn’t unreasonabe. If we manage to find th Higg’s Bosom (the so-called God particle everyone’s talking about recently), who know’s what we could do with it?
In short, I suggest that the predictions of what technology may be possible should be limited primarily to short-term futures (0-50 years, maybe 100 years if you’re stretching things), but beyond that what ‘can be’ is far from certain. Even commonly accepted laws of physics could potentially be wrong under certain situations.
Colin, thanks for commenting! You are of course right that we cannot assume that any trend will continue infinitely (as I discussed in my post about current fears regarding the Technological Singularity), and I’m not saying that something like a solid hologram is impossible, but what I am saying is that through the methods currently conceived, it is physically impossible. We could, with the ideas we currently have, create holograms that FEEL solid, but if you tripped and fell into them, they couldn’t catch you, as they might in Star Trek. As for using something like the God Particle, that strikes me as a bit like cheating in a science fiction story- in one of my early posts, I talked about Orson Scott Card’s recommendations about defining the rules of your world, whether fantasy or science fiction, in order to make it feel more real. Your world needs inner consistency for your reader to be able to become immersed. Having things like a magical genie lamp that grants infinite wishes, or a God Particle (or something like it) that suddenly makes all things possible, takes a good-sized chunk out of the dramatic potential of your narrative, and weakens the world overall. That’s why I’m such a proponent of doing your best to figure out how your story’s technology could conceivably work, and often the easiest way to do that is to look at what ideas are emerging today and to try to guess where they might go. Obviously no one can actually predict these directions, but you’d be amazed at how close some educated guesses have come (check out the book Neuromancer for an idea of what I mean). So, if you can give a reasonably satisfactory explanation of how Higg’s Bosom (having been found in your universe) allowed scientists to create hard-light holograms (among other things, I should hope), and weave it into an effective narrative, then you would meet my expectations. The Holodeck, however, does not. Not to say I’m any sort of authority on the subject, but this is my blog post. 😀
Interesting read. There is a theory that everything we see in the universe is already a hologram, I.e. that we live in a holographic universe. All that we see and touch could just be a complex wave function. This means that it’s possible to make a hologram of an object that looks and feels like the real thing.
A quick youtube search shows dozens of rudimentary 3D holographic display technologies being developed. Though I don’t think we’ve yet got the technology or computing power to record and then reconstruct all the light emitting from an object from all angles. You probably need photon detectors, and supercomputers similar to CERN and a way of re-emitting the photons as they appeared.
The touch or force-field side is not yet solved. There is one attempt to solve this using an array of ultrasonic transducers. These send air vibrations to a focussed volume of space, which you can feel, but it won’t stop you pushing through the vibrating air.
When we look at what makes things feel solid, it’s just the repulsion of our body’s electrons with the electrons of objects – we never actually touch anything, the electron charge alone creates the force and touch sensations. If it were possible to create a hologram of electrons, so that they replicated the structure of the original object, we could create hard holograms. The object could be represented as a (very) complex wave function I.e. ripples of electrons and photons in a volume of space.
If you delve a bit deeper into how electrons repel each other, you find out that they exchange photons. Therefore, all the objects you see and feel can be replicated using photons. The problem is, making a projector that can reproduce all the required photons in a volume all around you, without you interfering with the projection.
Another way to do this is with smart matter – programmable grains of material which can be controlled by electromagnetic fields. The material would reconfigure to represent physical objects. Intel is one company currently developing this.
An easier way might be to bypass trying to make the virtual/physical objects and just stimulate the brain to thinking it has touched or seen something, similar to The Matrix. This is much easier to do, but still requires a lot of computing power and a brain-computer interface.
You’ve got some great ideas there, James, but I do have a few bones to pick. First of all, it shouldn’t really be necessary to project light from every conceivable angle, as you describe in your first example. Computers can cheat by rendering an object in perspectives (there are already plenty of examples of this, although not in a quality that we would mistake for reality yet). You wouldn’t ever yourself see the back of an object at the same time as you saw the front unless its transparent, but then that’s still a perspective. With multiple people viewing the object, this becomes more complicated, but still not nearly as complicated as what you describe. The visual aspects are not really the hard part. Virtual reality visors, such as the Oculus Rift, are being designed to do just this sort of thing, although this isn’t a hologram, obviously.
Creating physical sensation, especially to the degree that the projection is actually solid, is the hard part. Programmable matter is probably the most direct method you described, however, this is the sort of technology that has an extreme impact on your story world if it exists, to the point that I wouldn’t myself go this direction simply because it would be a headache.Your electronic repulsion idea is intriguing, although I would disagree that we never “actually touch objects.” Objects do have physical surfaces and mass, so that the force impact is felt beyond just the epidermis. If you could generate a repulsion strong enough on the surface of the projection that it simulates the actual density and rigidity of the real-world object, then you would essentially be creating the Hard Light hologram I describe above. That does seem like it would require an actual facility like a Holodeck to pull off, though. I can’t imagine a mobile device could generate a force like that from every angle required to simulate a complete object, let alone an environment. At least, if it could, it would have (again) huge implications for your story world (where else would people use such a technology? What powers it? Isn’t this basically a kinetic field like Mass Effect’s , etc.). It could easily take over the story, which is not necessarily a bad thing. You could write whole novels on this, or the programmable matter idea (I wonder if anyone has yet?).
Thanks for the input. I’ll have to do another Science Fiction Problems to address some new ideas about this topic, addressing things like the programmable matter idea and how holograms would differ from the sort of virtual reality being developed currently in the gaming industry.
As of last month (27/11/2013) is was announced that “hard light” physics are here. As I always try to remind people; nothing is impossible, rather a probability factor is attached to it. Thus, logically speaking, its better to say it is possible for the world to be round then assume the status quo are correct 😉
The science behind it is called the ‘Rydberg Blockade’. Put simply, laser blast of photons through a cloud of cooled rubidium atoms, thus forcing the photons to condense and as a result form molecules. This means that not only are lightsabers possible, but they won’t burn your face off if held to close like enclosed plasma torches. Yet, lasers do cut through solid objects if made strong enough, thus theoretically it is possible to build deadly lightsabers (ionizing blades and extremely “hot” radiation) and also harmless cooled hard light in the form of photonic molecules.
As a hologram is merely a projected wavefront of visible light from our perspective, physical objects can reflect a wavefront of visible light. Now, combine that with the Rydberg Blockade, and we have a functional interactive solid wavefront of light.
Taking into account this phenomena was discovered by mistake whilst as team at MIT and Harvard were working on Quantum computers, it also means that we should have reliable quantum computing at a consumer level within a number of years. Add that to holographic interfaces, and it’s possible we could have intelligent interactive holograms in the future based on neurological simulations held within a solid photonic construct.
Great article btw, of course I reiterate that one should always refrain from strong words like “impossible” when the physics is not yet properly understood. Now we have made such advances within such a short period from this article, probability factor should always be the rule of thumb. Everything comes down to numbers, everything we know and do not yet understand is always dictated by the universal language, an omnipresent constant.
Joshua, thanks for your thoughts! I am a little confused by claim of future date announcement, however. Perhaps you should take a look at my post about time travel? 🙂
I of course agree with you that one should be careful using the word “impossible” when talking about physics, however, if you do a search for this term, you will find that I only said that it was impossible with current methods, and that at the time of the writing of this post, there was no known method. I did not intend to imply that such a thing could not ever be done, or even that it is unlikely. Frankly, I think holograms, like virtual reality, are just too darn cool and useful for us not to figure it out eventually. The method you describe could provide a necessary piece, however, we’ll have to wait to see if anyone makes the leap to this particular application. I certainly hope so!