I'm curious as to whether or not it is possible to have a rainbow at wavelengths other than visible light. I'm familiar with Snell's refraction law and why it is that they occur, but now what about other wavelengths, such as radio, microwaves, or IR, let alone much shorter wavelengths, like in the Ultraviolet or X-Rays.

Thank you for your time,

  • $\begingroup$ How would you detect it? $\endgroup$
    – Kyle Kanos
    May 7, 2015 at 2:12
  • $\begingroup$ @KyleKanos I don't know...using a camera that is sensitive to those wavelengths? I know there are CCDs capable of operating reasonably well (after all, look at what they're taking up on JWST). Perhaps if we looked out into the Universe we might see them weakly in nebulae or supernova remnants? $\endgroup$
    – bjd2385
    May 7, 2015 at 2:25
  • $\begingroup$ Yes, there is dispersion at wavelengths other than the optical, so there are "rainbows". They should be rather easy to produce in the lab, but I doubt that astronomical objects will produce detectable rainbows, they are simply not dense enough and most (expect gas clouds that are close to the solar system) have too small an angular diameter to produce a full rainbow equivalent. $\endgroup$
    – CuriousOne
    May 7, 2015 at 3:16

2 Answers 2


Fascinating question. But if you mean rainbows in other wavelengths from the Sun, yes to UV and IR, but no to Xrays. Simply because there's no significant radiation from the Sun at Xray wavelengths (see this graph for radiation per wavelength).

Most of the Sun's radiation is at visible wavelengths, which I guess is no coincidence. Life on Earth has evolved to use the light available!

There are definately detectable rainbows at other wavelengths tho. See here for pics in UV (slightly inside the visible rainbow) and IR (slightly outside).


Yes. It is possible to produce rainbows of Ultraviolet or X-Rays in the lab. The SLAC team has already built a tool to produce rainbows of X-ray.


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