What mechanism could cause a person not to cast a reflection?

Question

In a universe where science can seem like magic, but where everything needs to be explainable in "scientific sounding terms" and where there are no blanket no Hand Waive solutions - EG, it's magic so we don't need to explain it further - what mechanism could be at play in order for a person to be completely visible under normal lighting conditions by the human eye, but not have a reflection?

Context

Vampires categorically don't exist, but "something" is causing people who are exposed to it to resemble them in specific ways. Such as having no reflection.

Not exactly a super power, more a change that has occurred that has this (plus other things) as a side effect.

Answer 1

They're actually invisible, but humans can perceive them anyway by an unrelated non-visual means

... Cards on the table, since this supposes two separate unrelated mechanisms then it's a bit of an inelegant explanation. But it might fit with some other "science that seems like magic" things going on in your setting. If vampires are the only supernatural phenomenon in the world, this isn't the right approach - but if you already have established the existence of superhumans and psychics for other reasons, well, read on.

1. They're invisible in reality

Vampires are invisible in truth. Not only do they cast no reflection, but they also don't cast shadows, appear on analog or digital photos, set off motion sensors, etc.

If you find that full invisibility doesn't fit your setting, they might be only translucent, or have a monstrous "true" appearance that shows up in mirrors and cameras.

2. Humans can sense them anyway

Vampires do, however, broadcast their presence by some psychic means. So people can still mentally sense that someone is there, and interpret that visually because (without psychic training of their own) they have no other way to understand that sensation. A reflection or an image has no psychic presence, so you only see what's actually there.

They might appear differently to different people (how would you know, if cameras don't pick them up), may have other mental abilities such as mind-reading or hypnosis. With training or skill, a vampire may be able to change their appearance deliberately. A trained human may be able to identify vampires on sight, or locate them even if they can't be seen directly. Humans with a particular resistance to psionics will see the vampire's true (invisible) appearance. Animals which are sensitive will react unpredictably, so your dog may alert on the vampire even if they look normal to you.

Psychic phenomena are not scientifically possible, but they have a long history in sci-fi settings. If telepathy already exists in your setting, it's possible vampires have access to it.

Answer 2

Possible solution: Polarised light

It may indeed be possible to prevent light reflections - just not from all mirrors and not from all types of light.

For instance, if your vampires could reflect light from their skin that is polarised, (eg. in the horizontal plane), and your mirror has a polarised filter (in the vertical plane), then the reflected light would be absorbed by the mirror rather than reflected back.

Alternatively, sunglasses could have a polarised filter (many in fact do) and this would assist those wanting to 'detect' vampires by also filtering out the light reflected off Vampires, and they would appear 'black'.

The difficulty is now in ensuring light reflected off Vampires are polarised. This is a lot harder to do (easy of large horizontal surfaces for example the ocean) - but perhaps their skin instead of being made of omnidirectional skin cells instead were made of horizontal layered microgrooves (perhaps like our fingerprints) such that any light that bounces of their skin is polarised horizontally - then this may have the desired effect.

*Bonus extra - sounds a little technobabbley - but 'reversing the polarity' is almost a Sci-Fi trope now from the days of Star Trek or StarGate. You could have devices that 'rotate polarity' in order to detect certain kinds, or evidence of, vampires :)

Answer 3

Impossible

Sadly, what you're describing would be impossible. A reflection is just a more uniform way that light bounces off an object. As the person can be seen, light resembling their image is travelling away. If it interacts with any surface that can cast a reflection, it'll be a reflection.

You could go a technobabble way. Light can interfere with itself. You could say that any light that is coming off the person is detected, then some other light is generated to interfere with those specific particles. They could then make the light of the person fly away in a random direction. That will make the reflection next to nothing compared to the 'background' light.

It is technobabble as it is incredibly difficult to do. It is safe to say that it is so difficult as to be impossible, even if you knew where each photon is. As it is light, it is impossible in practice to detect, track, and counteract each photon. This is magic territory.

Answer 4

The only 'mechanism' I can imagine would be a high-tech "invisibility" suit that could read the light striking the suit from one side and project it on the other side. See This youtube clip for a lower-tech example of how it (sort of) works.

If the suit incorporated AI that allowed it to detect nearby mirrors and only apply the effect in the direction of mirrors, then the suit wearer would appear normally visible to casual observers, but invisible when observed via a mirror.

Answer 5

The AR Is Glitching Again

As explained by others, you cannot have a person who reflects photons which can be perceived by other people, but which will not bounce off mirrors. (Plus, somehow, I guess the mirror is reflecting what is behind the non-reflecting person?) However, all of this is only a problem if what the other people are perceiving is actually there.

(Some of?) the people in your world are wearing Augmented Reality (AR) glasses (or have a video feed integrated into their eyes, or even have a computer chip wired into their brains). The "person" who casts no reflection is not, in fact, there at all. They cast no reflection because the AR isn't quite good enough to estimate where the reflections should be and fill those in as well. Or maybe it's a glitch related to certain specific projections; the AR's AI image interpolation normally is good enough to do fill in such details, but does not for this particular image, for some mysterious reason.

If you want to ratchet up another level, the person IS there, but wearing active camouflage. The AR is helpfully highlighting the camouflaged person, but weirdly is making them look oddly normal, instead of just a vaguely human-shape blob. Still no reflection (or just a vague distortion in the mirror), yet those property wired see the intruder anyway.

Answer 6

I'm going to answer in a slightly different direction and issue a frame challenge:

Vampires categorically don't exist, but "something" is causing people who are exposed to it to resemble them in specific ways. Such as having no reflection.

Well, that statement is not entirely accurate.

Historically (as in, in most/oldest lore), vampires do have a reflection. They specifically do not reflect in mirrors, because the mirrors that would be contemporary to Bram Stoker's Dracula would be either Mercury mirrors or Silver Nitrate mirrors.

(Or, if it's an antique, a sheet of polished silver, which is functionnaly equivalent for our purpose.)

Vampire do not cast a reflection in those because:

• A - they lack a soul.
• B - Silver is (in folklore terms) a pure/holy metal.
• C - a combinaison of the two options above.

I'm only a folklore amateur, but I assume that Mercury (quicksilver) would have the same mythical effet.

However, manufacturing evolved and while we still call a step of mirror making process silvering, we do not necessarily use silver anymore.

So if you want your non-vampires to not cast a reflection in only some mirrors, that makes our task infinitely easier - since we don't need to worry about the smallest puddle of water.

From that point on, it is mostly about the mirrors they do not reflect in. As Pelinore suggested in comments, perhaps they are just a novelty item, a genre of flat screen that selectively do not display some people and [random technobabble] "uses generative AI" to paint over/fill in the blanks. This question is way less fun when we make it about the mirror rather than the individual, but it is a lot easier to answer.

Answer 7

Active Selective Targeted De-cloaking

I've actually thought of this problem before (although I don't remember in what context). So @Trioxidane is correct that, from the perspective of photons bouncing a mirror, they cannot be phisically made to choose what they bounce off of. Somehow, the answer made itself apparent while reading the qualities listed in @JBH's response.

There's no reason we can't "fool" those who are trying to see vampires into thinking they have no reflections. This answer is in the same vein of how a Star Trek bridge viewscreen presents a 3D image of the other side: by controlling where the photons go.

So, instead of trying to control what photons to when they hit mirrors, they instead control who to send photons to! Imagine that our vampire is actively cloaked, much like a Romulan Warbird or the personal cloaking devices of the Jem'Hadar (clothes and everything!) The cloaking mechanism scans its surroundings for observers (be it humans, pets, cameras or insects) and chooses which observers to send photons to and only in their line of sight! The net effect is that the only surfaces that receive photons that convey a vampires image are those of the eyes and/or lenses that the vampire has chosen to reveal themselves to.

Now, this system is incredibly complex and has drawbacks which can either be hand-waved away or made into plot points. For example:

• This is, first and foremost, a cloaking device. The system needs to be able to capture all photons heading towards the object it is cloaking (in this case, our illustrious vampire) and send them back in the same direction they were headed in, with the same physical properties (frequency, spin, etc.). In other words, all standard issues with cloaking devices apply!
• Some examples include: not being able to cloak all frequencies (for example being visible in IR or UV), high energy consumption, not being able to cloak excess heat (from the user and the high energy consumption itself), not being able to hide gravitational effects, and more!
• The selective de-cloaking mechanism is also computationally intensive (though, ironically, maybe slightly less-so than the cloaking mechanism): it must scan all photons received, perform pattern recognition and identify the targets it will send photons to. Not only that, it must be able to detect if the object scanned is the actual object or the reflection of that object from a reflective surface! LIDAR won't help since the mirror would reflect the lasers just as well. Old-fashioned RADAR then?
• Assuming you can detect mirrors, eyes, cameras, etc., a benefit is that you can choose who can see you! Only humans? Only other vampires? Can cameras see you? Bugs are annoying so they can never see you.
• Another benefit is the pattern recognition itself can be used to easily detect enemies hidden behind the shadows. More specifically: the system is detecting eyes and cameras, and our vampire can use that information to know the exact location of hidden opponents. Unless they're too hidden, as with the next point:
• The pattern recognition system will never be 100% effective: distant objects will be difficult to detect. Anyone observing our vampire using binoculars or a telescope will not be able to see them. Same for others being well-hidden or cloaked.
• But wait, how do vampires see other vampires? Maybe they don't? If they do, they'd need some way to identify themselves to each other! And how do you tell apart friend or foe? This identification act poses some risk because it requires the vampire to reveal their presence to others.
• Finally, I keep mentioning a "mechanism" but what kind of mechanism is this? Who or what is doing all the necessary computations for cloaking? Is the vampire's brain advanced enough to do this or is it some kind of implant? And what's catching and emitting all those photons? The answer to these questions likely depends on your universe.
• Bonus: Good luck figuring out why they'd go through all that trouble to engineer such a complex system. Perhaps they wanted to add selective de-cloaking for the psychological effect it would have on those around them? * Shrug * maybe this is the easiest part in all this.
• Bonus #2: The active de-cloaking mechanism doesn't have to send the real image of our vampire. It can display anything, even a swarm of bats!

I think that's a good-enough list. Good luck with your over-tech vampires! :D

Aside: the question itself isn't too bad. If it's rephrased by eliminating the technobabble angle and asking directly about its mechanism, it's a perfectly valid question.

Answer 8

I don't believe there is any physical mechanism by which this could happen, but there could be several psychological mechanisms that would permit it.

It could be a psychological effect happening in the mind of the observers, rather than a physical phenomenon that could be measured with scientific apparatus. Most of these ideas involve the observer being affected rather than the person/thing that seems not to have a reflection.

Hypnosis

Hypnosis could cause a group of people to accept a suggestion that they cannot see a person's reflection, and would claim and act as if they could not see the reflection -- even if physically there is a reflection. This could even make the effect be associated with specific people being observed. (e.g. "You can see Bob's reflection, but you can't see Alice's reflection.")

Drugs

In a similar line of thinking, there could be a psychotropic chemical in the environment that causes people to hallucinate in such a way that they claim that they cannot see reflections.

Migraines

It could also be widespread occular (retinal) migraines that under some ideal circumstances cause people to have a specific experience where they see the person but not their reflection.

For any of the above, it's reasonable to believe that the vampire-like person could be the cause of the phenonmenon as well, with just a touch of comic-book like science: e.g. Could be hypnotically persuasive, could have chemicals in their sweat like venomous toads, could have/be a source of radiation that causes inflammation of the optic nerve.

Fueled by mass misconception

Any of the above observer-based phenomenon could become (falsely) widely accepted as truth by a mechanism where a few people have the experience, and are supported by a few other "I also had that experience" reports on social media, which in turn fuel a widespread misconception that such people actually have no reflection, when in fact it was only a few isolated incidents.

My approach here is that it may not be necessary for the lack of reflections to be physically happening, but rather just for everyone to accept that it is happening.

Answer 9

Chameleon powers!

They're not actually invisible; they have skin like chameleons. They also have an autonomic reflex around mirrors that cause them to take on the appearance of whatever's behind them; thus giving the impression of having no reflection.

Honestly, I prefer Toph's answer, but I thought I'd throw my hat in the ring for a bit of fun.

Answer 10

If we are to technobabble lets to do it right. Vampires are not mythical creatures, they are some sort of quantum anomaly. They are not made out of regular matter. This gives them their powers. Anomalous matter does not obey the regular physical constraints. Any light that falls on them does not get absorbed or reflected as it should. Any light that is passing through them is affected by a field and becomes a duality. Likewise, any light that is reflected is affected and becomes the other side of the duality. Mirrors will realize the first reality and light passing through them becomes the light reflected off of the mirror. But due to the nature of human eyes, second duality becomes reality and the vampire can be observed. Cameras can act in a way that they look like a black blur.

Answer 11

People constantly ask "explain my magic via science!" questions on this site. The only problem with the idea is that the entire purpose of science is to dismiss magic and disillusion humanity.

It's impossible to explain magic via any means other than magic, but some people have to learn the hard way, so here goes.

Your hapless vampires must possess two qualities in order to not cause a reflection in a mirror.

1. The light reflected off their bodies must, for one reason or another, not be reflected back (at least in a way that we would expect... hold that thought).

2. Their bodies must also be capable of passing photons from behind them so that the area behind them is reflected, rather than themselves. In other words, for one reason or another your vampires are transparent (at least in a way that we wouldn't expect... hold that thought).

Answer #1

@Trioxidane is, of course, completely correct. What you're asking for (a scientific basis for one aspect of the vampire mythos) is impossible. For the very same reason that vampires, themselves, are impossible. Science doesn't allow it. But this is boring, so let's ignore it.

Slightly greasy solar atoms

There's a reason experienced and successful authors don't explain the gory details. They're irrelevant. This aspect of storytelling is known as Checkov's gun. Simply, don't explain anything that isn't relevant to your plot because if you do, you're distracting your reader from the story you're trying to tell. From Checkov's perspective, don't tell the reader there's a gun hanging over the fireplace unless that gun has a role to play later in the story.

And that's where slightly greasy solar atoms come into play. I'm a huge fan of Luc Besson's The Fifth Element During that movie it's necessary to reconstruct Milla Jovovich's character from a single cell. Do they explain it? Heck no! Most of the process is relatable to the audience as a far-future form of 3D printing, but skin isn't just flesh... it's an organ. How does Luc explain flesh growing over the musculature of Milla? "Slightly greasy solar atoms" are introduced to "force the body to protect itself" by growing skin.

Insofar as science is concerned, what Luc came up with has nothing at all to do with science. It's just some really cool technobabble that justified "what needs to happen next." So, rather than scientifically explaining a complex piece of machinery that had no purpose anywhere in the story other than in that one scene, Luc opted to simply hand wave it. Good for Luc!

And he's not alone. When J. Mills Goodloe and Salvador Paskowitz wrote the script for The Age of Adaline they explained Blake Lively's character's inability to age this way:

At 8:55 a bolt of lightning struck the vehicle discharging half a billion volts of electricity and producing 60,000 amperes of current. Its effect was threefold. First, the charge defibrillated Adaline Bowman's heart. Second, she was jolted out of her anoxic state causing her to draw her first breath in 2 minutes. Third, based on Von Lehman's principle of electron compression in deoxyribonucleic acid - which will be discovered in the year two thousand thirty-five - Adaline Bowman will henceforth be immune to the ravages of time. She will never age another day.

It's utter nonsense! But it sounds sciency, right?

To close or not to close the question

And that brings us to the problem with asking for a scientific explanation of magic. Do we close the question or not since the only response must be technobabble that has as much relevance to science as the lyrics of "Macarena" do to pancakes. So... at the risk of supporting a question that probably should have been closed as opinion-based or too story-based and at the risk of having this answer voted deleted as a lengthy comment, let's throw a nearly meaningless explanation (from the perspective of science) at you and see if it sticks. And if I'm REALLY lucky, you'll learn something about why it's insanely important how and why you ask questions here (because we're not here to help you write a story, we're here to help you build a world, thus "scientific sounding terms" isn't something we do...).

Answer #2

• If you're fortunate enough to live long enough to look at a vampire... to really look at a vampire... you'll see that they're slightly blurry. That's because they're vibrating. It's why a stake anywhere but the heart doesn't kill them. They have more in common with a cloud than they do humanity. What does this vibration buy us? Some light passes through them. Just enough to make the reflection in the mirror look convincing... unless you really look at the reflection and realize that the vampire-shaped area isn't quite as convincing as everywhere else.

• The light that bounces off the vampire, which would normally be reflected in the mirror, becomes, shall we say... wiggly. It's the vibration, you see, which causes the photons to go haranguing off into space in all kinds of ways and with all kinds of twists and spins. This isn't much of a problem for the human eye (unless you really look at the vampire) because the human brain is in the business of processing images into a comprehensible format. It's why you can see the shadow of your hand in a darkened cave. You're brain is perfectly capable of showing you the vampire! It's basically using the same capabilities that cause hallucinations — just in a useful way. But! When the light winging all over the place hits the mirror, combined with the natural imperfections of mirrors, the light is spread all over creation. So little comprehensible light can reach the human eye in such a case that there's nothing to use to recreate the vampire.

Your real problem isn't the vampire... it's the vampire's clothes! Those would be seen in the mirror just fine no matter what the theoretically science-based vampire can do. So, in your world vampires have neither scruples nor modesty. They wander around buck nekid so you can't see them in a mirror. (And most people think the vampire's ability to hypnotize people has something to do with hypnosis! Hah! It's really simple shock. Or awe. Kinda depends on which side of the fence you and the vampire are on.)

You know, you could increase the mass of the vampires to the point that the light behind them warps around them so nobody can really see them... but that would require the Earth to implode and time to stop, so we'll pass on that solution.

Answer 12

what if vampire exists like in 2 dimensions that somehow interfere in just some specific case

in the no reflection part, say imagine it's like 2 sound waves cancelling each other, now in the vampire reflection part it's just somehow interrupts the light wave in the mirror , this is a bit too far stretched lol

Answer 13

I suppose you'd have to guide the light absorbed by the person's body and redirect it suitably around to the 'dark' side so it hit the ground at the same angle and intensity as it would with the person absent from the space.

The person would therefore need to be coated with a close to 100% efficient light collecting medium which would:

• have absorbers for all direct (not specular) incoming sunlight

• memorisers to track each incoming photon for impact position and elevation

• conductors to guide the absorbed light around the body of the person

• emitters to radiate light appropriately (position and elevation of radiance) at the shadowy side of the person

I don't think optics technology is quite there yet on this one but it's an idea for you.

Answer 14

Budget cuts

As all of us are well aware, we're living in a simulation.

Someone, somewhere, is paying for this simulation. And they don't have an unlimited budget. High quality mirror reflections are best rendered via ray-tracing, which is 10x more expensive than normal rasterization.

As people familiar with vampire lore are well aware, not everyone becomes a vampire upon death. Specifically, only people who haven't settled their tax bill before death are punished with this malaise - to spend up to one eternity while being rendered in a low fidelity mode.

Answer 15

They're wearing a very special full body suit

They're wearing a suit that can control what light is sent from all parts of the suit, in every direction, independently of each other.

And it's configured to direct the representation of a human towards other humans eyeballs. So to another human, it looks like another human.

Towards anything that isn't an eye, it directs whatever is 'behind' them from that things perspective, so if they were standing between a camera and a painting, the suit would project the image of the painting at the camera. Essentially making it invisible.

It could even be a glitch that the mirrors reflective propeties makes whatever programming is running the suit not interpret the eyes looking at it in the mirror as eyes, and so it returns stealth to them.

This would also mean weird things for shadows (namely, it wouldn't have one, as it would be projecting the correct amount of light towards the floor to negate its own shadow...)

This technology is, at best, absurdly beyond anything we could produce, and at worst, probably in violation of a few physical theories as we understand them (we as in humans, cos I aint got a clue!)

Answer 16

...' where everything needs to be explainable in "scientific sounding terms"'

the mechanism you are looking for is Technobabble, think like star trek

Picard: Could it be Lore?

Data: No, sir. My brother's positronic brain has a type L phase discriminating amplifier. Mine is a type R.

Picard: Type R!

Data: Yes, sir.

if you only want scientific sounding terms then its not really hard sci fi that you're looking for

Answer 17

Vantablack++

If your 'Vampire' is painted so black they don't reflect any light, the light wouldn't bounce into the mirror; Meaning, no reflection. You could 'see' them by effectively being an cutout in the world.

They are entirely visible because they stand out starkly under normal lighting conditions, yet they produce no reflections. That said, while it isn't technically a reflection, you would see the black cutout in the mirror too. (or maybe you would see the metal behind the mirror glass?)