This is kinda a followup question to my earlier question about magical mirrors: Magical internet - unique addressing system

Two months ago, I discovered an ancient house in the middle of woods. As I scrolled through the books stored there, I realized that it belonged to a medieval witch who called herself Baba Yaga.

Among all her possessions, I also found two Mirrors. One was called Baba Yaga's Beauty Queen and the other was called Merlin's Happy Giant.

I found out that I can connect these two mirrors at instant, providing clear vision and sound from one mirror to another.

I also tested the distance of connection: I put these mirrors 1500 km apart and I had a clear connection. Also during this test I found out, that the "signal" seems to be following laws of physics, so the speed of transferring an image is the same as speed of light.

Moreover, amongst Baba Yaga's books, I found a "Magical Mirror Maker Manual" and I was able to follow and with the usual tools and chemistry accessible to nowadays's average citizen, I was able to make a third magical mirror, which I called Pavel's Wonder.

Again, I could connect this newly created mirror to any already existing mirror.

Is there a way to make money in today's world by selling magical mirrors which can provide sound and vision connection to each other?

Things to consider:

  • Mirrors can provide only one-to-one connection, while the iPhone in my pocket can do FaceTime with up to 32 people. (And my computer can connect me with any number of people I wish) EDIT, I made huge mistake here! In the linked question, I kinda hinted, that one-to-many connections are possible. Because this question is live for certain time, you can assume both (only one-to-one connection possible) or one-to-many connection is possible
  • Mirrors can only transmit sound and vision. They do not have any other "apps" as my iPhone already has.
  • Mirrors cannot take photos and/or selfies, neither can they store them in clouds or Facebook/Instagram
  • Speaking of which, mirrors cannot connect to the internet.
  • Yes, the connection between mirrors seems to be free and not requiring any signal from a tower and/or satellite. But I do not see any way how to make money on that.
  • Creating a mirror can be fully automated, using generally accessible chemics.
  • Creating first mirror by hand costed me about 50 US dollars in materials and two hours of my time. I tried creating another mirror, where I slashed the costs down to 35 USD and one hour of my time. Considering how I still did everything by hand, I can mass-produce a mirror in a matter of minutes for less than 10 USD manufacturing cost per pocket-size mirror.
  • I have no idea how the connection itself works. And I will care only if it brings me any money
  • Mirrors do not require any source of internal and/or external power to operate. But again, I have no idea how to monetize on this fact
  • The magical mirror acts as a usual mirror handling-wise. It can be broken and even if only small pieces are missing from the original mirror, you cannot make any connection to such mirror.
  • You can connect to any mirror if you know its identifier. Which means, every mirror has to have unique name. In the olden days it was done by naming the mirror by a magician and then including specific name of the mirror. However, you can name a mirror anything you like (I tried two new mirrors named Grzegorz Brzęczyszczykiewicz and хороший день and both worked fine)
  • The connection is made by stating out loud to the mirror where you want to connect: "Connect me to Baba Yaga's Beauty Queen" or "Spoj mě s Pavel's wonder"
  • Yes, the above means that the mirror understand natural language. I tested connection in Czech, English, Russian, German and Polish. As long as you pronounce the mirror name correctly, you get connected.
  • The mirror can be set to "accept all connections automatically" or "ask for accepting connection"
  • If the mirror is set to "ask for accepting connection", a voice from the mirror asks you in your native language if you wish to accept the connection. You are expected to give "Yes/No" answer. (Answer is understood in any language. Or, well, again, I tested here Czech, English, Russian, Polish and German languages)
  • Creating a mirror requires the sound "I name you name of a mirror". That sound can be recorded or computer-generated.
  • While I tried creating pocket-size mirrors, the manual is for "generic mirror". So I assume it would work for any size or shape of a mirror.
  • Magical mirror must be fashioned in one piece. You cannot make one magical mirror by joining two mirrors together. However, you can join two magical mirrors, but they would act as separate mirrors.
  • The process is easy and it can be reverse engineered. Sadly for you, I already filed a patent for this technology

Addendum: The mirrors seem to have their flaws. Being discussed here: How to limit magic mirrors so they're not overly powerful?

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    $\begingroup$ Mirrors do not require any source of internal and/or external power to operate. But again, I have no idea how to monetize on this fact - That's exactly the main reason why it would be beneficial. Plus you'd have no party in between to which you have to pay monthly. And you get the connection anywhere? That's a thing I'd buy right away, even if its size is too large to carry around. There is also potential for a market to expand on its functions, combine it with technology, automate it, make it more sturdy, etc. Use a small surface area to transmit data and there you go - internet. Maybe. $\endgroup$ – Battle Oct 4 '18 at 12:57
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    $\begingroup$ I really love the "thoroughness" and clarity of this question. It leaves very little open for the normal silliness. $\endgroup$ – pipe Oct 4 '18 at 14:11
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    $\begingroup$ Can the mirror be reverse-engineered, or is the mirror making manual more akin to a spellbook? You have no idea how this device works, so I don't think you'll be able to get a patent on it. If the mirror can be reverse-engineered, you have no protection from other people/companies making their own, so unless you've already got sizable production and marketing teams, you'll probably be outclassed by larger competitors. $\endgroup$ – Nuclear Wang Oct 4 '18 at 17:29
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    $\begingroup$ This question has been flagged as too broad (and lacks any reasoning why). I tend to agree with that assessment: the economic viability of a device (magical or otherwise) is only limited by one's creativity, and it's hard to identify which solution would be the "best" one. $\endgroup$ – Frostfyre Oct 4 '18 at 21:04
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    $\begingroup$ "Two months ago, I discovered ancient house in the middle of woods. As I scrolled through the books stored there, I realized that it belonged to medieval witch who called self Baba Yaga." What, the chicken feet weren't enough of a giveaway? $\endgroup$ – Arcanist Lupus Oct 5 '18 at 6:05

29 Answers 29


Your magical mirrors could replace 28,000 kilometres (17,400 miles) of Optical Fibres. The total costs of the cables currently laid is estimated to be about 1.1 billion (Source below article).


In simple terms, the communications happen by having an array of high-speed LED placed across the surface of the mirror, pulsing 1's and 0's in various frequencies of the EM spectrum (infrared, microwave, visible light, ultra-violet). The bandwidth capabilities of such a set-up would be orders of magnitude higher than traditional Optical Fibres. We are speaking of several Peta-bytes per second, using a single pair of 50-inch mirrors here.

You could take this further and have miniature mirrors embedded inside electronic devices and totally replace Radio-waves with mirrors. GSM, 4G, Wifi, Microwaves would all be brutally killed, given the high bandwidth and power-efficiencies of these mirrors.

Our networking protocols are pretty robust and allow interfacing between existing and new communication technologies, pretty easily. So, the new iPhone (or more probably Samsung) might support Pavel Mirrors as the cutting edge communication system. The monetising potential is several Billions for sure.

Since many readers on this site might not be familiar about how optic fibres work, here is an over-simplified description. Imagine you had one of these mirrors placed right in front of a Television Set and another in front of you. But, you are sitting miles away from the television. If you now point your remote-control at the mirror and press a button, it would still work and the TV would switch channels or increase volume.

Now imagine the TV's remote-control sensor is placed right against the mirror's surface and so is the remote-control also placed against the surface of the other mirror (the positioning matters). This would allow you to place multiple remotes and sensors and also run them with less power. Typical TV remotes use Infrared light. But, there are LEDs and sensors available for other kinds of lights, like Red, Green, Blue, Yellow, UV. This means you could tightly pack these sensors and still prevent them from interfering with each other. A cheap TV remote LED can only pulse a few thousand times per second reliably. But, there are LEDs that can pulse trillions of times per second in multiple light-frequencies simultaneously. These are the once used in Optic-fibres and you could use them here too (if you have Trillions of TVs or to send data across the ocean).

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    $\begingroup$ @Shadow - the internet is really a giant mesh of point-to-point links. In this case, the mirrors are just replacing the wires in the middle of some of the more expensive point to point links (intercontinental cables) $\endgroup$ – Fake Name Oct 5 '18 at 4:50
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    $\begingroup$ @FakeName I know, the answer made that pretty clear. But would you say those point to point links are "connected to the internet"? I would. I'm not saying we discount this answer or anything, but it would be interesting to see what the asker had in mind when writing that requirement. $\endgroup$ – Shadow Oct 5 '18 at 4:54
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    $\begingroup$ It seemed to me the author meant "no smartphone apps", which is still true here. $\endgroup$ – Arcanist Lupus Oct 5 '18 at 6:12
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    $\begingroup$ @ADS I think they have to create "micro" or even "nano" mirrors for this to work, These mirrors should replicate each other to actually have the communication that optic fiber needs. $\endgroup$ – Mr.J Oct 5 '18 at 6:27
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    $\begingroup$ @ADS the optical fibers are an artifact of the optical cable which this technology would replace. We would attach LED arrays and sensors directly to the mirror, just like with 8K displays and camera sensor fields. The signals might get transmitted via fibers again, but there is no need to glue fibers to the mirror. $\endgroup$ – Holger Oct 5 '18 at 11:56

The military and organizations that need absolutely secure data transmission, like government agencies and banks, would love your mirrors. The downside is that these will require some proof that your connection is indeed absolutely secure, so there will be research involved.

The biggest group that could profit from such mirrors are researchers.

Imagine how extremely costly it is to create a deep sea submarine. Now they can basically hang a Magic Mirror on a really long fishing line and be able to see the deep sea. Wildlife observation can be done in real time without hiking to remote places to change the batteries of a camera.

Imagine a new Hubble Telescope with Magic Mirror technology! You only need to transport the outer shell and one big mirror* into space. All the optical lenses, cameras and equipments that actually take and analyze the pictures can be stationed on Earth, easily maintained and replaced when better technology is available without sending them into space. * The helpful comments made me realize that I was mistaken. You have to transport almost the whole telescope into space, only the lenses and optical sensors can be stationed, maintained and replaced on Earth.

The same applies to space probes. You can send a Voyager III on its way now and replace sensors, cameras and other equipment here on Earth during its journey.

If any kind of optical and sound wave is transmitted through the mirror, you can use technologies like sonar, microwave, infrared, visible light, x-rays and many more with it. The possibilities are incredible.

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    $\begingroup$ @pipe this does not suggest replacing the optics with a mirror. The idea is that only the mirror need be transported into space, while the rest of the optics could remain on Earth, pointed at another mirror that connects to the one in space. $\endgroup$ – Monty Harder Oct 4 '18 at 14:49
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    $\begingroup$ @JohnDvorak The "big win" here is the ability to maintain and upgrade the sensors as technology progresses. You just send a 6m magic-mirror up with an RCS unit (controlled by a set of Optical Data Connections using additional mirrors, so that the Computer can be upgraded on Earth too), and have a matching one on Earth - then any new telescope innovations can be applied on this end. $\endgroup$ – Chronocidal Oct 4 '18 at 15:16
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    $\begingroup$ I suppose using in space telescopes is impossible. Telescopes investigates very small area 2.4 arcminutes. To see distant objects they needs exposure time for days. That's why orientation machinery (and fuel for it) is needed on space. Focusing system is situated before detector so you can't move it to the Earth. The focusing system is the most complex part of space telescope and the big mirror as part of it is most expensive $\endgroup$ – ADS Oct 4 '18 at 20:32
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    $\begingroup$ To supplement the Deep Sea Investigation value that you've pointed out, the mirror wouldn't need to have any sort of light making apparatus, because from the corresponding mirror in your hand, you can shine a bright light on it, and that will light up what you're looking at; If glare is a problem, then send down two mirrors anchored close to one another, one to shine the light through like a camera's flash, and the other to be observing through. $\endgroup$ – Davy M Oct 4 '18 at 23:12
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    $\begingroup$ @cybernard Pressure should do nothing to a solid object in water. Otherwise all submarines would be scrap metal and glass. $\endgroup$ – KalleMP Oct 5 '18 at 9:04

Another use for those mirrors is for light transmission, especially sunlight transmission.

One of the biggest problems with solar power, both electric, thermal or directly as light, is that it is inconstant. Night, winter, bad weather... But if you put mirror farms in hot deserts with constant clear weather in a way that there are always some in full sunlight, you solve that problem.

High-quality, natural sunlight, both domestic and collective, is directly available. To heat something, especially low-temperature like domestic heating or hot water, no need for burning fuel or using electricity. Simply use a thermal oven or water heater lit by one or more mirrors. Solar farms, both photo-voltaic and solar-thermal, can output constant electricity 24/7, and can be protected from weather.

You have the potential to revolutionize energy generation and distribution here, but only start exploring it once you made a boatload of money through other application. It is an industry with extremely powerful vested interests, and you will need to have your own major lobby to really develop it. Given what you've stumbled into, you should be richer than some nations in a few years anyway, so this shouldn't be a problem.

  • $\begingroup$ give the supposed high cost of the mirrors it sounds like it would be cheaper to build many extra solar plants than use magic mirrors. $\endgroup$ – John Oct 4 '18 at 16:48
  • $\begingroup$ The mirrors would be a significant part of the cost of the solar plant, but it is compensated by having the solar plants always working at full capacity. In addition, many uses that were previously requiring electricity (heating and, to a lesser extent, light) don't anymore - in fact, electricity generation would probably come last, light and thermal being much more straightforward. Depending on how good the mirrors are, parabolic (mundane) mirrors could be used to concentrate sunlight on them and actively cool the (magic) mirrors in order to decrease the size needed. $\endgroup$ – Eth Oct 4 '18 at 17:51
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    $\begingroup$ except it wouldn't be continuous not unless you put the mirrors in space. $\endgroup$ – John Oct 4 '18 at 18:01
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    $\begingroup$ "So, what's your ceiling light made of?" "It's a magic portal to the middle of Sahara" $\endgroup$ – John Dvorak Oct 4 '18 at 19:36
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    $\begingroup$ A question on resolution change. If I have large mirror collecting sunlight, and a small mirror receiving it, is the energy intensified? If not, then the inverse is true such that I could have a million 1 cm mirrors pushing sunlight through 1 million 3 m mirrors for even more light? $\endgroup$ – Jammin4CO Oct 5 '18 at 14:47

Nobody seems to have monetised them evilly.

Sell them to banks, law firms, businesses, high power executives, and city bars. Either utilitarian, for bathroom/toilets, or with high class frames, for boardrooms, meeting rooms and (in private houses) bedrooms.

Now listen, watch and record them, on a remote mirror.

You only need to catch a few people discussing business changes, negotiations, or plans, with a colleague, while they wash their hands or check their appearance, or a heads-up on some shifty practice or secret affair. Or even pay them to put a small mirror in the CEO's office.

Either advance business knowledge, or blackmail. Your choice. Both could pull in a fortune.

Personally, I'd go for business intel any day, much more valuable. It's worth watching mirrors for a few hours when there's an important meeting, to get a few days advance knowledge of a proposed takeover bid, new product or strategy, or anything else. A company's shares can go up or down, and you can profit heavily either way - many, many times a year, and no way to prove insider trading or illegality.

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    $\begingroup$ Wouldn't they notice you recording them when they no longer see a reflection in the mirror, but your face/room/camera instead? $\endgroup$ – Ajedi32 Oct 4 '18 at 18:21
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    $\begingroup$ How about a penny sized version? All you need is sound, so you could hide a small mirror behind a shelf or on the underside of a desk $\endgroup$ – John Locke Oct 4 '18 at 19:50
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    $\begingroup$ Just put a real mirror on your side, problem solved $\endgroup$ – Fred Stark Oct 5 '18 at 6:51
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    $\begingroup$ Neat solution :) $\endgroup$ – Stilez Oct 5 '18 at 7:35
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    $\begingroup$ I don't see how this is a significant improvement over current bugs and spying technology? What you've described can be achieved with current real-world technology. $\endgroup$ – Martin Carney Oct 9 '18 at 16:59

High-frequency Traders

Nanoseconds matter in high-frequency trading. The people involved in these businesses spend millions on dedicated processing hardware and point-to-point fibre links. In HFT, the curvature of the Earth matters, and the difference between the speed of light in air and the speed of light in glass also matters. These mirrors cheat both, and get the speed of light in vacuum and can shave hundreds to thousands of miles off round-trip times between distant locations by going through the Earth rather than round it. There are other applications, but these are going to be the ones who have the highest willingness to pay for the extra performance and reliability you can deliver in the short term.

Once you're established (and most importantly, have the capital to invest in some personal security to stop ne'er-do-wells from stealing the tech or kidnapping you) you can move on to lower-margin groups like telcos, space administrations, intelligence agencies, and suchlike.

  • $\begingroup$ Can agree - (not HFT, but fintech) - we definitely pay a premium for rack space and such super close to the exchanges. $\endgroup$ – Jeutnarg Oct 11 '18 at 14:43

Reactionless space drive Magic mirrors don't conserve momentum. When a normal mirror reflects light, the momentum of the photon is reversed, giving an impulse to the mirror. Now if that light is caught by a magic mirror and the second magic mirror is pointed back at the normal mirror, I get the same photons back again. My thrust is limited only by how close to perfectly reflective my normal mirror is.

Klingon cloaking device You have paired mirrors on opposite sides of the hull. When engaged light that hits one mirror is passed to the opposite mirror. Note that this won't be perfect. Off axis incoming photons will be displaced to the side. This can't be corrected easily without additional spells.

Free energy Same concept as above, but designed into a wheel like device. Thrust rotates a wheel, which spins a generator.

Cheap streetlights. A mirror is matched to one on the opposite side of the world. Similarly flashlights that never need new batteries.

Industrial Heating If it handles sufficient intensity then a mismatch in sizes makes some interesting industrial processes possible. (May have some problems with the laws of thermodynamics, but hey, this is magic, right?) Consider a 2 meter mirror connected to a 1 mm mirror. Put the big one outside. Now you have about 4 kW coming out of a hole 1 mm in diameter. Welding/cutting tool?

A bunch of these all pointing at a crucible.

If you can develop very high temperature mirrors, it should be possible to build rocket engines that use H2 as reaction mass. This gives you a huge increase in specific impulse. Or use water. Not as efficient but cheaper.

Space Lasers aka Reagan's Star Wars Mirror is in space. Lasers are on earth. You still need a pointing/tracking system, but the heavy stuff is down here.

Unlimited bandwidth for space probes Present deep space probes are limited by the power required to send data back to earth. Some were sending images back for months after they passed their target.

Untraceable internet Build the mirror into the same case that has an led. Pulse the Led. A single pair creates a simplex channel. Two pairs give you full duplex. (While the mirror itself conducts light both ways, receiving while the led a half mm away is shining may be difficult. The Dark Web is going to love this.

Cellphones work EVERYWHERE No lost signal. Be a boon for remote locations, where otherwise communications have to use clunky radios or satellite communication. Also you aren't spending energy broadcasting. Use a kindle type screen, and a phone should be good for weeks. Criminals and conspiracy theorists would love this as it's inherently untraceable.

Universal fast internet No more of this, "I live in the sticks, and can only get 33Kbaud dialup. Or pay $100/month for 1 Mbit satellite"

CO2 sequestration & fish farming Put a larger (1 km mylar film?) mirror in some sunny climate. Put the matching mirror on the abyssal plain in the ocean. Warm up ocean water. The sunlight pouring out is absorbed by the water. Hot water rises, carrying with it nutrients (upwellings are reasons arctic waters are so productive) The abyssal water is lower in CO2 than surface water. The nutrients create a plume of phytoplankton where it meets the surface.

Solar Power Storage Solar thermal storage right now has a lot of plumbing issues with heating the molten salts while keeping them from solidifying. Put mirrors on the surface with their companions in the salt tank. Tank heats up until it's radiating energy out as fast as it's being poured in. This tank is easy to insulate and it doesn't have to be on a high tower. Note that for this use, you may have to use pyrex or stainless steel mirrors.

Home heating You have an insulated water tank in your basement with a mirror in it. Mirror partner is in the opposite hemisphere so it's summer is your winter. Circulate hot water as needed to warm your house.

Thermal Underwear. Apply magic mirror to thread. Put the matching garment in a warm place. If the mirror works with infrared, you now have a layer of that is at the temperature of the warm place. In summer you could air condition the home mirror and be cucumber cool during a heatwave.

Apply this to walls with the corresponding mirror in the ocean or lake, and you have cheap air conditioning. Might have condensation issues.

Put one on the abyssal plain, and one in the air out of the sun. Radiant energy vanishes into the mirror, and the surface cools. Water supply from condensed moisture in deserts?

High Altitude Observation platforms. Build a balloon, spray it with 1" of very low density foam. Mirror on the outside and the inside. Lower half of the inside of the balloon is painted black.

Navigation systems Right now we have a bunch of expensive satellites in orbit to run the GPS system, and there are a bunch of reasons that the location isn't perfect. Suppose you have a set of broadcast mirrors that allow attachement by anyone. Instead of a microwave signal, you encode the same sort of protocol on an LED behind the broadcast mirror. Your MagicGPS receives the signals from 4 or more mirrors and uses this to compute location. The computations are much simpler, since the mirrors are fixed in space. Since they aren't in orbit there is no relativistic correction. (Ok, still a small one if you are way above or below a mirror) No atmospheric jitter. Should be able to easily get sub meter accuracy.

(I'm trying to figure out if a magic mirror a place in either ring laser gyros or fiber optic gyros. Do mirrors preserve phase information?)

Interesting art Your mirrors are made of VERY thin glass. (I've seen a glassblower pop a glass bubble, and the shards floated around for minutes.) So you have very thin mirrors floating in water. The matching mirrors are in varicoloured lights.

Which leads to Full 3D displays Multiple mirrors are printed on tinsel like strips of clear plastic. The strips are hung in a liquid that has the same index of refraction. Ideally for this you want a mirror that only works one way, and is transparent to local light. But failing this if the tank mirrors are tiny compared to the pixel volume it will still work. Not that this will work as a 'ghost' world. One object won't block another.

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    $\begingroup$ Differently sized mirrors definitelly break the 2nd law of thermodynamics. $\endgroup$ – Tomáš Zato - Reinstate Monica Oct 6 '18 at 15:13
  • $\begingroup$ @TomášZato would you expand on why? Seems to me that most telescopes do this optically. $\endgroup$ – Sherwood Botsford Oct 7 '18 at 15:19
  • $\begingroup$ No, because they curve the light in the process, whereas you'd directly get the rays closer together without curving them in the process. Think about this this way - make one mirror small enough and the other big enough and you have a black hole. $\endgroup$ – Tomáš Zato - Reinstate Monica Oct 7 '18 at 16:38
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    $\begingroup$ @TomášZato We're talking about magic mirrors that appear to ignore the laws of physics anyway. I wouldn't worry about it personally. $\endgroup$ – Corey Oct 8 '18 at 4:44
  • $\begingroup$ @Baldrickk That's not how any of this works. Google Kugelblitz for an example. Once an event horizon forms, there's no way back even if this horizon apparently destroys it's origin. @ Corey OP was trying to avoid breaking laws of physics. $\endgroup$ – Tomáš Zato - Reinstate Monica Oct 8 '18 at 10:54

Sell them, at extortionate prices, to people who need guaranteed connection in inhospitable locations. Sailors, mountaineers, backpackers, spelunkers of various kinds (Thanks Arcanist Lupus), the military: all these people will pay through the nose for a powerless, guaranteed to connect, uncrackable communication method.

As for repeat custom: mirrors get broken. You can count on people to need replacements every so often. If the initial price point is set correctly and you control the means of supply then you can make a killing even without ‘subscription fees’.

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    $\begingroup$ We don't know if it's uncrackable though, even though the rest of your features are well worth it. $\endgroup$ – pipe Oct 4 '18 at 14:15
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    $\begingroup$ @pipe: I generally assume anything involving magic isn't going to be cracked by any mundane signal analysts, though your point is valid. $\endgroup$ – Joe Bloggs Oct 4 '18 at 15:05
  • $\begingroup$ backers would not want this, we go out so we don't have a connection :P $\endgroup$ – Reed Oct 4 '18 at 20:48
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    $\begingroup$ Also good for anyone who works underground - miners, sewer workers and the like. Cell coverage is awful underground. $\endgroup$ – Arcanist Lupus Oct 5 '18 at 6:24
  • $\begingroup$ @Reed Some go out to get connection from weird places, and get the scifi feel of it all. $\endgroup$ – hyde Oct 8 '18 at 6:10

NASA, version 2:

Powering spacecraft in the outer solar system is quite problematic. Solar cells are weak at Jupiter and pretty much useless beyond that. That means only nuclear generators--and those need synthetic (expen$ive!) isotopes to run and seriously limit the power available to the spacecraft. (We are currently using up stuff made in the cold war. A few more probes and that will be gone--and there will be no source of RTGs for the outer solar system.)

Instead, we put a mirror in our probe. We shine through it a very bright light of the right frequency to get maximum yield from the solar cells on the other side with minimum heat production. Yield should be far above current efficiencies. As has been given in another answer this mirror is also the communications device. Presto, we just replaced the entire power and communications setup with a couple of pounds of stuff. As a secondary effect power isn't so critical anymore, we don't have to jump through every hoop imaginable to minimize power consumption. I wouldn't be surprised if NASA would pay $100 million for a mirror pair.

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    $\begingroup$ Also, niw the mirror is our probe, since you can see through it. $\endgroup$ – Tomáš Zato - Reinstate Monica Oct 6 '18 at 14:43
  • $\begingroup$ @TomášZato And you think the only thing NASA mounts on a probe is cameras?? And even if it were you need something to point it. And you need lenses. $\endgroup$ – Loren Pechtel Oct 7 '18 at 1:40
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    $\begingroup$ Solar panels aren't nearly as powerful per unit mass as nuclear isotopes, and the panels degrade over time. NASA still has to pay a lot of money to launch the probe; ongoing power requirements over many years of budget allocations may not offset the savings of 'free' solar power over onboard nuclear power. $\endgroup$ – brichins Oct 8 '18 at 17:55
  • $\begingroup$ Congratulations, power and data (!) transmission over interplanetary distances is solved, now we can finally send some tiny probes to nearby star systems. They can even use the photons coming out of the mirror as propulsion! $\endgroup$ – JohnEye Oct 9 '18 at 11:42
  • $\begingroup$ Scale it up. Launch two probes, one into a low orbit where its mirror can pick up lots and lots of sunlight, and then your deep-space one where the sunlight coming out of the mirror replaces the heat from the isotope decay for your generator. Plus all that bulky, heavy, power-hungry communications equipment gets replaced with tiny, cheap, energy-efficient, relatively secure mirror-based transmission system. $\endgroup$ – Perkins Oct 9 '18 at 18:51

Another way to the mirrors can be used is for data transfer. An optical pulse sender and Receiver at the other end would be a way to get data across continents absolutely secure with the speed of light. Stock exchanges, Banks, Military, etc would use such a technology for even faster communications.
You could manage a Profit from high Quality mirrors that have not or only a tiny amount of surface errors so the optical pulses come through bright and clear.

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    $\begingroup$ Add a second sender and receiver for bidirectional optic data transfer, and you prove the OP is wrong about not being able to connect to the Internet. You can use the mirror to hide your true location, appearing to be located wherever the "base" mirror is. $\endgroup$ – Monty Harder Oct 4 '18 at 14:51

Congratulations, you've just created the new state-of-the-art mobile phone screen.

Instead of carrying around a bulky, battery powered phone, you can just have a mirror that interfaces with a larger device at your home.

No more connection issues either - the age of the landline and mirror is in, and with our cloud partnerships, you can travel without having any significant latency.

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    $\begingroup$ You still need the touch screen electronics and the audio electronics. It's not just a mirror. $\endgroup$ – Loren Pechtel Oct 5 '18 at 15:51
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    $\begingroup$ @LorenPechtel The mirror also transmits sound. And there are LED based toutch screens, look them up, it's cool. $\endgroup$ – Tomáš Zato - Reinstate Monica Oct 6 '18 at 14:46
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    $\begingroup$ @LorenPechtel Given that there is already gear which can track where a person is looking using cameras, I doubt tracking where their finger is will be a major technical challenge. $\endgroup$ – Roland Heath Oct 7 '18 at 14:32
  • $\begingroup$ @TomášZato yeah, IR LEDs around the edge of the mirror being used. When fingers make contact with the glass, it sends an IR reflection back to an IR camera (as simple as a webcam with an IR pass filter) on the other side of the link - finger detection done. This is how the original MS Surface (the table) worked. $\endgroup$ – Baldrickk Oct 8 '18 at 8:54
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    $\begingroup$ just make sure you are careful not dropping your phone: currently the screen might still be useable somewhat with a cracked screen, but the magic mirrors die completely even if they get a small scratch $\endgroup$ – SztupY Oct 8 '18 at 13:14

Congratulations, you just violated the First Law of Thermodynamics and discovered a perpetuum mobile.

The implications are too huge to consider in a short answer, could be anything, but I presume blowing up the Universe will happen in near future.

Consider these of your conditions taken together:

  • Mirrors can [only] transmit sound and vision
  • Yes, the connection between mirrors seems to be free
  • you can assume both (only one-to-one connection possible) or one-to-many connection is possible

So, mirrors are not only cost free transfer of electromagnetic and acoustic waves, the one-to-many connection additionally means they can actually MULTIPLY photons: you shine a light into a 1-to-2 mirror setup, you get 2 rays of light coming out of 2 different mirrors. Since each photon carries energy, you've just got yourself rayful of energy for free.

Presumably, if you connect the output of the 1-to-2 mirror to other mirrors, so that they loop back to the first mirror, the only energy loss will be during the distance between mirrors, more than compensated by the fact that you will get 1 ray for free.

What you want to do with this, is have somebody who understands physics better, put safeguards in such a setup, so that when the energy levels exceed safety margins the mirrors are blackened. Considering, however, that the energy increase speed seems to be at the speed of light, the chances of you not blowing up the Earth along with your mirrors seem slim to me. But then again, IANAP(hysicist).

If you really need advice on how to exploit free energy, maybe better sell the patent to somebody. But consider that it is not as if you can hope to conceal the secret for long, as the patent is a public thing for all to see. Somebody will make the setup ... and sooner or later somebody will miscalculate and blow up, at the best case, only the mirrors. In the worst -- maybe this part of galaxy.


Mirrors is the wrong term to use for such devices, they do act more like the portals from the Valve computer game "Portal", as mentioned in the comments.

Consider this loop:

mirror loop

The mirror A is paired with mirrors B1 and B2, so that everything you shine into A, goes to both of them. It will receive an ever increasing stream of photons, which, it seems to me, would blow a normal mirror to smitherens due to absorbed heat. Unlike the magic mirror, which appears to be not a mirror at all in fact.

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    $\begingroup$ Even with one to one connection, you still break the 2nd law. You can now use the mirrors to concentrate the energy in ways that break the law. I also wonder how do the mirrors treat virrual particles. $\endgroup$ – Tomáš Zato - Reinstate Monica Oct 6 '18 at 14:55
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    $\begingroup$ @Eth If you combine gravitational redshift with portal infinite loop minus the air friction, you obtain a device that permanently transforms low-energy heat radiation into energy-rich blue / ultraviolet light / gamma rays. Simply put one mirror above the other in the gravitational field, and collect the energy-rich photons that travel from the top mirror into the bottom mirror. Looks like infinite energy for free. $\endgroup$ – Andrey Tyukin Oct 6 '18 at 18:10
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    $\begingroup$ @Eth How? Do the mirrors permanently measure their gravitational potential, and adjust the redshift somehow? Where in the question is this specified? If some external entity interacts with the looping stream of increasingly high-energy photons and redshifts the photons somehow, then this entity is extracting energy from the photons - and that's exactly what Gnudiff said, a perpetuum mobile, so everything blows up and everyone dies ;) $\endgroup$ – Andrey Tyukin Oct 6 '18 at 19:30
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    $\begingroup$ @AndreyTyukin (sorry, pressed wrong key) Not knowing what make the mirrors work in the first place, it is impossible to say how. And while such effect isn't described in the question, they would be invisible to the discoverer before sending it to a physics lab. For what we know, they could be using wormholes, which would have some funny effects on causality once someone starts to move them around at a fraction of c... $\endgroup$ – Eth Oct 6 '18 at 19:35
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    $\begingroup$ @Eth I don't know, maybe... the current specification does not allow to say whether the mirrors could quickly destroy the planet, so I'd say it's a bit underspecified ;) Assuming that the mirrors don't correct for all kind of strange relativistic effects, I'm not sure whether it would be "invisible to the discoverer before sending it to a physics lab", or whether it would be more like a short & painful & deadly criticality accident with blue glow if you accidentally hold the mirrors in the wrong way. $\endgroup$ – Andrey Tyukin Oct 6 '18 at 19:52

Unlimited Free Clean Energy.

Take the fuel rods out of a nuclear reactor. Put a mirror in there. Launch a paired mirror into a really tight orbit of the sun, putting a spin on it such that it always faces the sun. That mirror will be bombarded with blindingly intense light. That light will pass through to the mirror on Earth, and be emitted into the reactor. Now you're powering a nuclear reactor (now a fusion reactor, if even that, since the fusion is happening offsite) without using nuclear fuel. But the point is, you can get unlimited free clean energy from the Sun by just putting a mirror up close to the Sun

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    $\begingroup$ Wouldn't the mirror melt, and thus no longer function per the "magical mirror acts as usual mirror handling-wise" rule? $\endgroup$ – Ajedi32 Oct 4 '18 at 18:20
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    $\begingroup$ That rule was added after my answer. I assumed the mirror would allow perfect pass-through of light without converting any of it to heat. The mirror on the sun side is in vaccuum, so light would be the only source of heating. The mirror on the earth would be causing the water around it to heat up to boiling, but as long as the cooling towers are working right, the temp will be kept constant, as the heat is consumed at the same rate it is coming through. $\endgroup$ – Jared K Oct 4 '18 at 19:04
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    $\begingroup$ It couldn't have been added after your answer. This answer was posted an hour ago, and the last edit to the question was 6 hours ago. $\endgroup$ – Ajedi32 Oct 4 '18 at 19:19
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    $\begingroup$ This answer can be cut down. It's irrelevant if the eaeth-based location is/was a nuclear reactor, with or without fuel rods. The important thing is that it's a heat conversion engine (which is what any heat-based power plant is, after you take away any existing coal/gas/radioactive/whatever). Also, rather helpfully, any mirror far enough away from the sun for its orbit to be sustainable without propulsion system, would also be extremely hot, but well below the "insanely hot" levels where building it becomes hard, or your earth-side plant is melting. $\endgroup$ – Stilez Oct 5 '18 at 13:34
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    $\begingroup$ @M.Herzkamp Then change "Unlimited Free Clean Energy" to Chain Reaction's "Cheap Clean Abundant Energy" (Morgan Freeman voice) $\endgroup$ – Martin Carney Oct 9 '18 at 17:20

An ISP could make the mirrors part of their Internet infrastructure by bolting the mirrors down and lining the surface as densely as they can with fiber optics. You didn't specify the size of your mirror, but if it's about as big as an iPhone 4, it will be $2.91 \times 1.94 = 5.65$ square inches, and since each cable is about $0.005$ inches across, you can fit $582 \times 388 = 225,816$ cables on your mirror if they're grid packed (even more if they're hexagonally packed). You would likely need some spacing between cables to account for alignment errors, but that's still quite a bit of available bandwidth that an ISP would pay through their ears to have.

  • $\begingroup$ You can probably do better than that, since a mirror is effectively holographic. You can effectively double the number of connections by bonding a custom optic to the face of the mirror and fanning out the fibres, and more complex arrangements can do better still. In practice, the bandwidth of a pair of these mirrors is going to be limited by how much you're willing to spend on transceivers rather than anything else. $\endgroup$ – Yurgen Oct 4 '18 at 16:50
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    $\begingroup$ Yeah, this is crazy. A customer could buy internet service from someone in another state, or in another /country/. However, a major issue is that the user can connect his mirror to /any/ other mirror that he knows about. Buy two, and you can execute a Man-in-The-Mirror attack on /anyone/ on the line. $\endgroup$ – notovny Oct 4 '18 at 23:36
  • $\begingroup$ @notovny I was imagining that the ISPs themselves would put these in their datacenters, so that would probably happen by default. Still cool, though. $\endgroup$ – TheHansinator Oct 5 '18 at 0:06
  • $\begingroup$ @notovny You need to know the name of both mirrors to execute a man in the mirror attack. And it gets you nothing if the digital signal is encrypted. $\endgroup$ – Sherwood Botsford Oct 7 '18 at 16:15

Video conferencing that actually works.

  1. Build a really big warehouse.
  2. Make a whole lot of mirror pairs.
  3. Put one mirror out of each pair in the warehouse.
  4. Build a robot that can push the mirrors around such that they face each other.
  5. Sell the remaining mirrors as the world’s only dedicated, lag-free, zero-setup, video-conferencing system.
  6. Charge a mint for each mirror.
  7. Profit.
  • $\begingroup$ As any mirror can connect to any other mirror, why would you need robots and a warehouse? Just get the owners of each mirror to call each other directly. $\endgroup$ – Baldrickk Oct 8 '18 at 9:34
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    $\begingroup$ What if the users of the mirrors are never told the mirrors' actual names? If the user only knows a "number" that can be used in a protected database to find the true name of the mirror (which is used at creation/pairing time to link the members of the pair, and is never needed again unless a mirror is broken and needs to be replaced). That means that you can charge monthly and/or per-connection fees and maintain an ongoing revenue stream, rather than collecting a one-time sale only. Alternatively, you can sell both mirrors in a pair to someone who wants dedicated point-to-point service. $\endgroup$ – Monty Harder Oct 8 '18 at 15:03

It may not be possible to use mirrors through the Internet, but it is possible to use the Internet through the mirrors. A crude version of this would be to hook a computer up to a light source and a camera, then point it at a mirror. Do the same thing with the computer on the other end. As long as both computers agree on how a basic signal should be encoded (maybe using different colors of light, so that if all the lights are off you know something is wrong), this setup can act as the physical layer of a network connection, replacing things like copper wires or fiber optic cables or radio waves. Then the computers could link up, probably with something akin to PPP, and you're on your way.

(Hey, they've figured out how to use the Internet through carrier pigeons; they'll figure out how to do it through magic mirrors).

Why would people do this? If there is no signal travelling between the mirrors, then communications become much harder to intercept. Intelligence agencies will love them. So will banks. Criminal enterprises will probably also be fans.

  • $\begingroup$ intelligence agencies will love them for themselves, but they would hate the criminals using them, for the same reason criminals would love them $\endgroup$ – Baldrickk Oct 8 '18 at 9:32

If these mirror don't require any physical connection, and yet they are able to transmit light and sound in perfect fidelity from one point to another at the speed of light, it is very likely that they can do even more than this.

You have no idea how it works, but are able to follow simple instructions which it sounds like anybody could do to build the mirror, so the principles involved appear to be fairly simple. Specifically, it's not like a building a large computer where you need a billion dollar semi-conductor fab to build the wafers, it's more like the first transistor where you can build one out of materials that you are able to obtain. Depending on how magic works in your world, it may be that like building a transistor radio that takes up a kitchen table, there is a 50 year or more technological growth curve where this sufficiently advanced technology can be studied and refined. Or alternately, magic in your world may be totally separate from physics and follow its own rules or logic.

Either way, the value is this is potentially incalculable. If you are willing to put the time and effort into it yourself, you could raise venture capital and lead the effort to research how the mirror works and additional effects that are possible. If you can send light, what other things can you send? Can you send gravity? If you can send sound, can you send other kinds of physical vibrations? Can you send matter? If so that would be of immense value as your magic mirror is now a teleporter. The sorts of research into exactly what sorts of things you can do and what sorts of things you might be able to do with tweaks to the mirror could take years, but also disrupt entire industries. If you don't want to put all the work in, you very likely could make a great deal of money selling the information on how to build the mirrors to a third party - just be sure to put together all these thoughts into what exciting and valuable possibilities could be made available and require that the deal allows you to reap rewards proportional to the advances are made, instead of some fixed sum of money.

Even if your mirrors are only ever capable of sending light and sound, how much light? How much sound? Is it just the visible spectrum or other parts of the electromagnetic spectrum? If there is no attenuation of the signal, then a large mirror was placed in orbit closer to the sun, and a great deal of energy could be beamed directly to the Earth for a variety of uses.

Even if your mirrors actually behave no differently from a camera / screen setup, as the other answers mention you still have what seems to be a more reliable system not requiring wires and possibly even noise free transmission mechanism. What if millions of these mirrors were made, but microscopic in size, you could have a revolution in computers as you eliminate the need for comparatively slow electrical paths. Is there any limit on how many point to point connections can be created at once? It sounds like you may have a better crossbar mechanism as well. The possibilities are endless. Play your cards right and you'll be rich beyond your wildest dreams!

  • $\begingroup$ just an add on, in general any kind of actual magic would be far more valuable in the real world than one might think because it bypasses many of the constraints and trade-offs which burden the real world- magical universes either tend to undervalue and underuse magic, or else have magical problem counterparts which negate the advantage magic gives. $\endgroup$ – Michael Oct 4 '18 at 20:06
  • $\begingroup$ If it follows rules and logic then it's science not magic - just science we don't understand yet. I guarantee a lot of physicists will be taking these mirrors apart :) $\endgroup$ – Tim B Oct 4 '18 at 21:32
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    $\begingroup$ Also, food for thought: if these were invented before signal transmission were an established industry, then hamming codes would probably never have been developed because there would have been no need for them. $\endgroup$ – Wildcard Oct 5 '18 at 21:18

You could really spruce up your inner city flat with a sea view of the Bahamas. I know this probably wouldn't be nearly as lucrative as some of the technical breakthroughs - but it could still make a tidy margin.

You could sell 'windows' to any landscape you liked - large mirrors paired with a second mirror in a beautiful location.The more sought after location, the higher the price.

The natural lighting (with, I assume, perfect 3D), full natural sound, and no power consumption would make this much more desirable than a similar digital screen. Also the remote end would need little maintenance, except occasional window cleaning (A bird dropping could be very annoying though!).

You could also create full surround experiences, by constructing two small buildings of paired magic mirrors, with one set of mirrors pointing in, and the other pointing out.

You would have to consider possible jet-lag effects, if you placed paired mirrors in different time zones. In some cases this could be turned into a benefit however - such as being able to watch a meteor shower in the Himalayas at tea time in the UK. Imagine the potential for an exquisite, romantic, restaurant experience, when used with the full surround concept.

It could even be marketed as a cure for seasonal affective disorder. Those dark evenings pulling you down? Here is some equatorial sunshine!

Edit thanks to Mark Carney's comment There are a number of issues with using these mirrors in this way- in that, as with windows, sound and light transmission go both ways. Two significant problems are peeping toms and noisy neighbours. The windows could be used by bad actors to spy into people's homes. You could also hear the noise from neighbouring mirrors, if the away end of your mirror was placed near to other mirrors.

However this can be turned into an advantage, as you can charge for solutions to these problems. They could range from simple soundproofing with double glazing for the average householder, to having your own guarded lot with a guaranteed minimum distance from sources of sound pollution for richer clients.

  • $\begingroup$ Sound and light transmission is two-way. An unforeseen problem with many such "pretty view" mirrors is that you would hear sound not only from the location, but echoed from the far ends of neighboring mirrors. And anyone on the landscape side could peep into a large number of peoples' homes and offices. $\endgroup$ – Martin Carney Oct 9 '18 at 17:30

They would be great to overcome security measures preventing signal to get in or out of buildings, places, in short: spying devices. As long as they aren't very unique-looking, you can install them in place of real mirrors, maybe even replace windows, etc. You might need to do a bit more research to make them one-way and transparent, respectively, but it would be probably worth the gain (unless you get killed by people who don't want such a technology out there).

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    $\begingroup$ As I understand the OP, when the mirrors are connected, it's a two-way connection. It will be very apparent that it's no ordinary mirror as soon as it's activated. $\endgroup$ – Nuclear Wang Oct 4 '18 at 15:25

If you're the evil sort, you can make money from this in all sorts of different ways.

Don't reveal your discovery to anyone, ever. Slowly acquire all of the major mirror manufacturers until you control the entire market. Start selling magic mirrors, but don't tell anyone that they're magic. Only sell one mirror from each pair, and keep the other hidden in storage. Once your mirrors have become ubiquitous around the globe, buy the most powerful industrial laser you can find. Now, you can activate a mirror for a brief moment and blast it with your laser, destroying whatever's on the other side of the matching mirror without any warning. For a subtler approach, you could use something like a cyclotron instead and irradiate your victim while they sleep. Since nobody else knows magic mirrors even exist, the crime never gets solved.

Hire yourself out as an assassin. Extort money from anyone, anywhere. Mail someone a mirror in a box and rig it to activate as soon as the box opens. The possibilities are endless.

The truly evil sort could even come at it from the other direction. Sell the mirror pairs as the amazing two-way communication device that they are, and wait for the fad to catch on. As the other answers indicate, people will quickly develop all sorts of creative uses for them. Now, you can step in and make lots of money by selling mirror blocking technology. Want to make sure your corporate boardroom or mafia safehouse isn't mirror-bugged? Want to make sure your citizens aren't using mirrors to bypass government surveillance systems? Tired of teenagers sneaking mirrors into your movie theaters to avoid buying tickets? Well then, you'd better pay up.

  • $\begingroup$ While the gist of your answer is unaffected, I think you misunderstood; mirrors aren't matched pairs. Any magic mirror can connect to any other magic mirror if the user knows the unique name of the mirror they want to connect to. $\endgroup$ – Martin Carney Oct 9 '18 at 17:35
  • $\begingroup$ @MartinCarney That makes it even easier, then. Instead of hoarding all the matched mirrors, all you'd need to do is keep the only record of each mirror's name. $\endgroup$ – bta Oct 10 '18 at 17:18

Hello, NASA. I've got these nice deep space communication relays for you. For $1,000,000 each, we can set up a paired link requiring only one pound payload, no power, no danger of interception, and really high reliability. We've been running some tests and managed 100kbps, but we think 10s of megabit is possible. Yes, you can verify this all works on the ground. No problem. The patent number is 383121323.


The military would eat this up.

If you are a soldier, this is the single greatest invention to ever make your life saver. Not because this invention is useful by itself, but because it has tons of applications in the field.


Some people have already pointed out your mirror's use in communications. This by itself is impressive- talking to someone a country away is difficult when you are in hostile territory that has little communications infrastructure. A mirror is secure, dependable, and doesn't need electricity to call home.

Imagine a building full of mirrors, filled with experts in the field of warfare. First, there's the commander. They can relay orders to all the mirrors in the building via a PA system. Then there are doctors, tacticians, counselors, explosives experts, anyone a soldier could possibly need to talk to for any kind of advice. Soldiers can even talk to their families every once in a while. All of this is possible without risking a single one of those experts into the warzone.


Life as a soldier is pretty hard. You're stuck in enemy territory for an indefinite amount of time, and you can't even get some decent music. With a mirror, you can just ask your counselor to play some music or a video from a computer on the other end. (Either all of the mirror's functions will use voice commands and voice recognition, or everyone will have a dedicated operator who turns the music on for them, calls for the counselor, etc.)


As if that wasn't enough, you can weaponise the mirrors. Just pull a large mirror out of your pack and say "laser", and a second later, your mirror is shooting high power lazer light at your foe, incinerating them and setting their clothes ablaze. No ammo, bullets, or charging required. The laser also makes a good fire starter. Assuming you haven't given up on guns in favor of the clearly superior mirror technology, a weak laser can be used as a sniper scope.


If you need to really take the weapons to the next level, you can have your mirror shoot gamma rays, x-rays, or any form of radiation you want. It's a pretty cruel death for anyone on the receiving end, but microwaves can be used to cook your rations, and two soldiers with their mirrors facing each other can be used as an x-ray machine, able to see inside anything between the mirrors. You can see exactly what each soldier in an enemy camp is doing inside their tent, and you can locate where all of the weapons are stored.


This is probably the most useful flashlight ever made. It needs no batteries, and the brightness is adjustable. Some of the side benefits of this flashlight, aside from seeing in the dark, is its possible use in signaling or as a flare, and its ability to blind when at full brightness.

Compact size

I don't think other answers realize that you can have two mirrors of different sizes. A soldier can hold a small mirror while the mirror on the other side is nice and large to get a good picture, and to focus anything shining through the mirror down to a more precise point.

Captured weapons

Because only one person in the entire world knows how to make the mirrors, the enemy won't be able to make mirrors to spy on your army. Typicaly, when a soldier is captured or killed, the enemy takes their weapons and communication devices. That's impossible with mirrors. First of all, when the enemy looks into the mirror, suddenly his head is balsted off by a laser. The enemy can't use a comadeered mirror anyway, the operator or voice recognition won't do it. The easiest thing for the enemy to do with the mirror is to smash it before you figure out how to send an explosive payload through and blow them all sky high. Initially, when the enemy doesn't know the limitations of the mirror or how it shoots lasers, the most subtle way to kill your enemies is to shine gamma or x-rays through, giving anyone near it radiation poisoning that will be noticed much later. When the enemy figures out that the mirror is two-way, they will try to send their lasers through to kill anyone on the other end that they can and destroy whatever equipment is there, so the best course of action is to destroy or disenchant the mirror before the enemy can use it to their advantage.


Speed-of-light communication with no signal deterioration or noise? As in, no matter how far away I place the mirror, I will not have to spend more energy to send to it, or more computing power to try to decypher the response? Sign me up! And for dirt cheap, too!

Lots of Ideas on the practical use for this have already been posted as answers, but it all boils down to this: the magic removes the two biggest issues we have with communication. Any military would love it, any space agency would LOVE it (if a mars rover could just blink a LED at a mirror instead of radioing a sattelite in orbit which then laser-pulses towards a sattelite orbiting earth which in turn radios the ground base or somesuch, that would be sweet)...

Heck, there's currently plans to send microsattelites towards the nearest star. They'll be in transit a couple decades at least, but equipping them with your mirrors would at least make the "and send the data back" part a near non-issue (although the lightspeed limitation would mean waiting another 4+ years for the data. Still better than waiting the same time and then getting a garbled, weak mess of a signal!)

Also, note that telescope resolution is limited by the size of the telescope - so a bigger mirror/lens is better... but that same size can (with enough computing power) be emulated by having multiple small ones at a far enough distance. Loss-free communication between telescope sattelites and the ground station via magic mirrors would be invaluable.

In short: Any space enthusiast will love this!

  • $\begingroup$ Blink a LED? Nah, put a fiber optic connection through it! It took more than a year for New Horizons to beam home it's data. With this it would have happened in realtime (not counting lightspeed lag.) $\endgroup$ – Loren Pechtel Oct 5 '18 at 15:54

Most of answers were focused on data transmission like improved version of fiber-optic channel. Althought I liked evil solution from @Stiliez and energy transmission from Sahara by @Eth I would like to talk about casual contacting.

First, like @Elmy and others mentioned, there are many people who need communications where electrical power inaccessible or too limited:

  • Long-term expeditions made by ethnographers, geologists, speleologists and to poles
  • Residents of remote villages where it's too costly to lay data cable
  • As improvement of cameras installed to investigate animals in wild. (Set up first small mirrow in wild, second in dark silent room with recording devices)

Second, someone would want to communicate secretely.

  • Any spy would happy with reliable, undetectable and un-suspicious communication channel with Center
  • Strategic submarines in particular and Navy in general
  • Goverments and corporations would be intrested mostly in solutions which guaranties not the fact of communication but content of communication.

And third, the most dangerous for civil society, as spying devices for goverments (or, probably, for corporations). Scenario is the same as wild animals: first mirroc is small and hidden while second mirror set on small dark silent room with recording devices.

  • Spying for enemies both actual or potential or just political opponents
  • The worst scenario was described by Orwell: each mirror spying for everyone (it's cheaper than many cameras which require data and energy cables)

The simple answer is that you make money off a thing by selling it for more than it costs you to make it. The thing doesn't even have to be useful. Ty Warner became a billionaire by selling useless stuffed animal dolls ("beanie babies"). Seems like a genuine magic mirror could be the next hot novelty gift for whatever holiday season is around the corner, with a decent ad campaign and marketing team. ("As seen in Fantastic Beasts 3, really works!")

If, as the other answers suggest, they have useful applications too, so much the better - you could make yourself a millionaire many times over selling cheap novelty versions to Harry Potter fans, and a billionaire by selling higher quality versions to industry and technology companies which will undoubtedly find numerous uses you never envisioned. (As is the case with countless modern inventions - air-conditioning was invented for the printing industry, microwaves came about from military RADAR, computers were used to break encrypted military communications before being used to deliver porn and other fringe uses, etc.) In the end, it doesn't really matter what uses you find for them, it's the uses that everyone else comes up with that will make you a fortune.


Simple, patent the technology. As you can see in the numerous answers given to your question, there are endless applications to this new technology.

As a single individual, you are severly limited in capital, production capacity and business ideas and applications compared to large companies. If you patent and release the technology to the market, every new idea and application of your techology will increase your fortune and visibility. A million individuals will always have more ideas then a single individual, and with every new application a new market opens up to you.


You sell them to a high-speed trading brokerage.

They already put up billions of dollars to shave milliseconds of transmission speed; you can own that game for the next 18 months or so.



This questions reminds me of PGR chips from first books in Ell Donsaii series Only differences were: - transmission time was checked and was found to be instant (not lightspeed but instant)(theory predicted just that) - small amount of power (several watts) was needed - point-to-point only and no voice commands - it is not 'mirror' - it's data link (if you need mirror - add camera,display and cpu)

This was enough to get Ell (creator of basic theory and inventor of this practical application) hundreds of millions of dollars in royalties in first years (and billions - later). This was also caused issues with communications companies of various kinds (which was solved by licensing devices to them).

I don't understood why same thing doesn't apply to magical mirrors.


Wow. Lots of answers about what you could do with them - the list of which is pretty much endless - and not so many directly addressing your actual question:

Is there a way to make money in today's world by selling magical mirrors which can provide sound and vision connection to each other?

Why yes, yes there is. In fact there are several ways you can do it, and some of them don't even have ethical problems.

  1. Assuming that you can't stop others from creating them, your patent guarantees that anyone who is making these things in the areas covered by the patent are liable to pay you royalties on their manufacture.

  2. Demonstrate the mirrors to the major manufacturers of fibre optics. Tell them that you're ready to go to market but could be convinced to not do so if given enough financial incentive not to.

  3. Setup a registry for mirror names and require anyone who is going to licence your process to purchase a subscription to the registry.

  4. Sell mirrors that have names that cannot be pronounced by humans and licence a device that will connect those mirrors.

  5. Only sell mirrors that are pre-paired, using names that are virtually impossible to figure out. Any attempt to reconnect the mirrors will break the connection and only you can re-connect.

  6. Sell the patent for a ton of money and let someone else figure out how to make money off it.

  7. Sell some mirrors for a small profit, let others examine them and figure out how to recreate them, become the greatest patent troll in the history of the world.

There are probably many others in a similar vein.

Ultimately though you'll probably be wanting to get as much money as you can right up front, because eventually the technology will get out of your control. Inside of 5 years there will be factories in China churning them out for pennies and trading them on Wish free plus postage. Second generation mirrors will have integrated electronics to facilitate connections, people will be hacking the mirror network by computer-driven name scans and auto-connect DoS, etc. Take the money and run :)


Use them in hard-to-reach or at least hard-to-network places. Bottom of the ocean. South pole. Outer space. If you could launch a few dozen into orbit, every observatory with a decent telescope could be a Hubble, using mirrors to bypass the atmosphere. They could also guarantee communication (untrackable?) between submarines and HQ, allowing them to stay submerged and stealthy. Exploration of the Moon and Mars would no longer have the logistical headache of having to relay communication across interplanetary distances. You could even contact your Mars probe when the Sun is between our two planets.

I also second the idea of using them for solar power. Leave one for me in the Arizona desert and I'll put the other in my house to have natural sunlight in wintertime. Or I'll point it right at a solar panel to charge my off-grid power system.

  • $\begingroup$ Why not just launch the panel into space so you can get light regardless of the time of day? $\endgroup$ – John Locke Oct 4 '18 at 19:43
  • $\begingroup$ I thought of that, but I wasn't sure what kind of weird and harmful radiation that might shower onto my houseplants. Also I think it'd raise the price way above $10 per panel. I could probably buy a hundred panels (one for every desert in every time zone) for the price of one in space... $\endgroup$ – workerjoe Oct 4 '18 at 20:08
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    $\begingroup$ Ok, how about this: one big mirror in space shines light through a mirror on earth. The ligjt coming out goes through a piece of glass to block radiation, and the light shines through a bunch of the enchanted mirrors that go to the customers. Now you only need 1 large mirror, and that sunlight makes heat which can be captured as energy to help pay for the system. $\endgroup$ – John Locke Oct 4 '18 at 21:27
  • $\begingroup$ If the magic is such that one "sending" mirror can broadcast to several "receiving" mirrors, that radically changes the picture, because then you have infinite possible multiplication of energy. It sort of breaks the laws of the universe, but that's magic for you, right? $\endgroup$ – workerjoe Oct 5 '18 at 1:44
  • $\begingroup$ No, I didn't mean it that way. The big mirror in space is enchanted to one on the planet. Then, because of its large size, its light shines onto multiple smaller mirrors. Each of those mirrors is linked to one mirror in a customer's house. Also, the post doesn't say mirrors have to be the same size, so you could have a ton of tiny mirrors receiving the light each linked to a slightly larger mirror in a customer's house. $\endgroup$ – John Locke Oct 5 '18 at 1:49

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