Aliens are coming to conquer Earth.

And they have a special capability to help them.

They can "see" the entire electromagnetic spectrum with their eyes.

How can I justify this vision/eye using science or pseudo-science?

Additional background information:

They plan to "see" all our communication done using electromagnetic waves (cell phone towers, radio waves, microwaves etc). Since most of our communication passes through these mediums, they are going to "visually decode" our transmitted information, phone/video conversations, launch codes, satellite and telephone communications etc. The various countries are unable to unite to launch a coordinated attack on the aliens due to this.

Their brain is also evolved enough to do on-the-fly decryption beyond capabilities we humans posses.

The plot revolves around how humans are forced to use only face to face communication. Audio waves are are not electromagnetic but mechanical in nature, which the aliens cannot "see".

An interesting reference: Komar can perceive ultraviolet after cataract surgery

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    $\begingroup$ They plan to "see" all our communication done using electromagnetic waves ... to "visually decode" our information.... Not likely. Most of our data is effectively text converted to binary run through a compression algorithm, before being converted into an analogue signal. E.g., a digital image is a description of the pixels within, something like, "pixel 1,[located] top left [of colour]Ox12345, pixel 2...". Video takes each frame as a separate image and so on. All the aliens could see would be flashes of light at high frequencies, like a disco ball. Let's hope they aren't epileptic. $\endgroup$
    – nzaman
    Oct 28, 2017 at 7:08
  • $\begingroup$ I have expanded the "see" part - Their brain is also evolved enough to do on-the-fly decryption. My focus is on how to justify the "eye" part. They are not using equipment's to see. Just their own eyes. I am looking to get a plausible explanation (anything not based on magic). For example, humans are trichromatic. Should the aliens have additional cones/rods/receptors in the eye? Does Earth science as of now do this in one single equipment? In short how can I explain this ability of the Aliens to see the entire electro-magnetic spectrum in a non magical pseudo scientific fashion? $\endgroup$
    – user3526
    Oct 28, 2017 at 7:30
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    $\begingroup$ You will need different detectors. You also do not need the entire spectrum since anything beyond ultraviolet gets absorbed by our atmosphere and cannot be used for transmitting signals. I'd suggest that (in addition to reading a bit about the em spectrum) you turn this one into several questions for all the relevant areas. How an organism would detect microwave radiation differes from how they would detect radio waves $\endgroup$
    – Raditz_35
    Oct 28, 2017 at 7:32
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    $\begingroup$ Oh great let's blind them quickly drones(radio wave), spam tweets(microwave), get the remote(IR), smoke detector(weak gamma), I'll teach u how to DIY X-ray tube😎 $\endgroup$
    – user6760
    Oct 28, 2017 at 9:17
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    $\begingroup$ What advantage does your story derive from the aliens receiving our signals biologically rather than using technology? It seems to me that the critical plot point is their superior decryption abilities, but those abilities don't need to be innate to function the way you need them to. $\endgroup$ Oct 28, 2017 at 13:45

4 Answers 4


Technically we are seeing the electromagnetic spectrum, too. Just limited to the part between 350 to 700 nm.

TL;DR: Won't be plausible.

The reason why we don't see more is that it has never been a beneficial trait for evolution to pressure us through this path. Some animals see UV or IF, but none see more than that. There is no necessity for it. You could explain it with genetic engineering and modification though.

The bigger problems are to do with electromagnetics: Not only is communication often highly directional, so unless you are the target you wont notice it, but also encoded. You'd have to know the encoding and calculated MBs of Data within miliseconds AND interpret them. Brains are not meant to do that. And also you'd have to decrypt military encryptions in the same timeframe. (Which includes solving currently unsolvable math problems)

Also as people pointed out in the comments: you could spam and blind them

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    $\begingroup$ Good answer. I'd only add size. It is hard to make em detector smaller than ¼ of wavelength. With 700nm it is doable as chemical compound. At meters long waves, it gets funny. $\endgroup$
    – Mołot
    Oct 28, 2017 at 10:01
  • $\begingroup$ @Molot are you saying that the physical size of the Aliens eye would limit them from seeing eletromagentic waves above/below a certain wavelength? I guess you could expand it into an answer. $\endgroup$
    – user3526
    Oct 28, 2017 at 10:08
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    $\begingroup$ @user3526: he meant the size of the sensors. You can't use 1 sensor to detect everythin properly. Our eyes have 3 different ones even for the tiny part of the spectrum we see. You'd need thousands of different single sensors stacked next to each other. Your resolution would suffer. Also not every wavelenght is focused the same way by a lense. You'd have massive distortions, too, unless you had hundreds of different eye types. $\endgroup$ Oct 28, 2017 at 10:25
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    $\begingroup$ @ArtificialSoul I meant both, actually. And to think about it, user may be right. I'll try to write an answer later. $\endgroup$
    – Mołot
    Oct 28, 2017 at 10:30

I don't think this is workable.

In general, a detector has to be on the same scale as the wavelength. You can make it somewhat smaller, but not, say 1/1000 the wavelength. Broadcast VHF TV uses a wavelength of several feet. UHF gets down below a foot. 3 GHz gets down to about 3 inches.

So at that frequency the sense is more akin to hearing.

At the other end, broadcast A.M. radio a station on 1000 KHz has a 300 meter wave length. To get efficient transmission, a quarter wave dipole antenna has to be 75 meters long. Yes you can make antennas for pickup at this band that are under a meter.

General observation: It's hard to make a sensor that will pick up more than a few octaves of anything. Human ear is good for about 8 octaves. It's just barely an octave for light. Multiband radios switch in different components for different bands. There's some shared circuitry.

Decryption on the fly: You are postulating that the aliens either have built in quantum computers or that they can factor the products of 100 digit prime numbers in their head in real time.

All the Terrans would need to do is change encryption keys faster than the aliens can think. Or use longer keys. Or spread around one time pads. Or broadcast random noise. Or broadcast endless streams of cookie recipes, and only the 7th letter of the 3rd line of instructions is meaningful.

In addition most of the communication right now is NOT on EM, but is on fiber-optic cable.

It's also multiplexed. A cell tower get's its feed either by fiberoptic cable or by microwave relay. The microwave antennas look like snare drums mounted on the mast. They typically are directional to a degree or two, and have a range of 10 to 30 miles. A link may carry many conversations, each encrypted differently, mixed up in some combination of time and frequency multiplexing.

Military communication may use frequency hopping. Not only encrypted, but several hundred times a second, it switches channels. If both radios switch at the same time, no problem.

Another technique for secure communication is to broadcast very low level signals on multiple channels. The receiver adds the signals. The noise on the average cancels out, the signal adds.


It is simple enough problem.

Their spaceships are positively flooded with reconnaissance micro-drones and cryptographic computers with advanced AIs. Their clothing is basically a massive EM sensor array. As are the skins of all their vehicles. They also have mature brain-computer interfaces and advanced personal AI assistants.

So everything in their vicinity will be detected by the abundant sensors. The personal AIs will automatically classify all data on whether the person should know of it and forward compressed and filtered feed up the chain. The personal AI can also decode and decrypt communications that has been broken already by the big cryptographic systems above. Relevant and decoded information will then be shown to the user.

Higher levels of the chain will then collate and analyse the data they were forwarded. They will look for patterns that lower AI might have missed. They will look for relevant information from elsewhere. They will classify, decode and decrypt any data lower AI failed to. Any relevant data produced is then sent back to lower levels for further use.

If you wanted a biological solution you should have said so. Although in this case a biological solution would still work more or less the same. You'd just replace the computer network with a hive mind of different castes of aliens that have been genetically engineered for their specific functions. To, for example, "the scouts" to have much better sensor capabilities than would make sense for evolution. Or for "the analysts" to have a "natural" ability to decode digital communications and decrypt digital cryptography. So even if you wanted a strictly biological solution you are probably better off allowing technological solutions and then mapping the solutions to biological ones?


LaForge on Star Trek Next Generation had a visor which translated the entire electromagnetic frequency into neural inputs which his brain interpreted as "seeing".

From this answer on https://scifi.stackexchange.com/questions/36107/why-does-geordi-la-forges-visor-see-a-wide-subspace-spectrum-and-not-just-visib

The VISOR, acronym for Visual Instrument and Sensory Organ Replacement, was a medical device used in the Federation to aid patients who had suffered loss of eyesight or who were born blind. The VISOR detected electromagnetic signals across the entire EM spectrum between 1 Hz and 100,000 THz and transmitted those signals to the brain through neural implants in the temples of the individual via delta-compressed wavelengths. (TNG: "The Masterpiece Society") The result was a vastly different visual acuity, with VISOR-wearers able to see in the infrared and ultraviolet ranges and beyond. To normal Human eyes, the images relayed through the VISOR could seem disorienting and unfamiliar. (TNG: "Heart of Glory", "The Enemy", "The Mind's Eye")

If you accept scientific handwaving, TNG waves with the best of them. Your aliens have VISORS like Jordy.


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