I have seen many pictures of stars that were taken in the UV or IR spectrum. Others have pointed out that they are scaled down so as to map to visible elements within our capabilities. Could Wi-Fi waves be registered in a picture or video in such manner? How would the world look with all the microwaves around if mapped in the visible spectrum?


That is absolutely something you can do, and it has been done: https://www.rtl-sdr.com/generating-a-wifi-radio-heatmap-with-a-helical-antenna-antenna-rotator-and-a-hackrf/

The everyday world looks a lot more blurry than you might expect, which is because the wavelength of 2.4 GHz is 12.5 cm and blurring is unavoidable for objects about the same size as the wavelength (along with all the usual causes for blurriness that you might expect from a visible light image).

Similar things have been done at a wide range of other radio frequencies. RADAR is essentially this, but with the radio-frequency-equivalent of the depth sensor that is likely in your phone camera if it’s a recent model. This general approach is also used for radio astronomy, which in turn led to the discovery of the cosmic microwave background,

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    $\begingroup$ Thank you! that was exactly what I wanted to see. Too bad it requieres a big device to do that. $\endgroup$ – Enrique Feb 17 at 14:52

...pictures of stars...taken in the UV or IR spectrum. Others have pointed out that they ...are scaled down so as to map to visible elements within our capabilities.

I don't know what "scaled down" means in this context or, what you think "our capabilities" are, but I suspect that you may be over-thinking the problem:

Cameras don't capture light; They detect signals, which may, in some cases, be visible light.

The position of each pixel in a photograph corresponds to a particular direction from which signals of some kind arrived at the camera. The brightness and the color of a pixel are representations of some arbitrary attributes of whatever kind of signal that the camera is designed to detect.

Can't emphasize those two words enough: representation and arbitrary.

In conventional, visible-light photography, the brightness of a pixel is a representation of the brightness of the light that reached the camera from a particular direction, and the color of the pixel is a representation of the color of the light reaching the camera from that same direction.

Conventional cameras don't work that way because of any physical law. It's not because the camera somehow "captured" the light, and that's what the light looked like. Cameras work that way because somebody decided, that they should work that way, because the result is a pleasing, natural-looking representation of the scene.

In other forms of photography, the brightness and the color of the pixels can be arbitrarily chosen to represent any attributes of the signal that the "camera" is able to detect. In many types of astro-photography (UV, IR, X-ray, microwave), the brightness of pixels represents the intensity of the signal. If intensity is the only attribute measured, then sometimes the both color and brightness are used to show intensity. (That's especially common with thermal-imaging cameras where blue-ish colors are assigned to "cold" (i.e., low intensity) pixels, and reddish or yellowish colors are assigned to "warmer" (i.e., higher intensity) pixels.)

Sometimes, in astronomical photography, the "camera" will capture two or more different wavelengths and so-called "false colors" will be arbitrarily assigned to the pixels to show the relative strengths of the signals at those different wavelengths.

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  • $\begingroup$ Thank you for your answer. You framed it in a new way for me, I was thinking in terms of bounced light, but of course wifi signals go through things and perhaps we can only see brightness and not reflection. $\endgroup$ – Enrique Feb 17 at 14:55

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