Is There a Maximum Wavelength for Electromagnetic Radiation?

[tomwilliam]

Is there any lower limit on the frequency of electromagnetic radiation? I imagine that beyond a certain frequency it becomes impossible to detect, but is there anything in the maxwell equations that establishes a maximum wavelength (besides the limits of the size of the universe)?
Thanks

 

[zhermes]

I'm pretty sure there isn't any constraint on how low the frequency can get, numerous theories do make some upper limits though.

As an aside, I'm not sure what effect even the finite size of the universe would have because of weird boundary conditions, and other cosmology stuff... I don't think any theory could accurately tell you the properties/details of wavelengths comparable to that of the universe; can anybody affirm/deny that?

 

[Dr Lots-o'watts]

Classically, the longest EM wave simply corresponds to a static electric field, such as point charge that is fixed in space. There is no classical limit to how slowly you can make it move (a body at rest tends to stay at rest).

Considering quantum theory and the uncertainty of known energy though, the answer is less obvious.

 

[JDługosz]

Several "popular" and more technical books I've read point out that there is no lower limit. The photon can have arbitrarily small energy, which means that the symmetry it embodies is perfect and unbroken. Because the photon has no rest mass, it can have an arbitrarily small energy.

 

[pmacias]

for your question! I can confirm that there is indeed a maximum wavelength for electromagnetic radiation. This limit is determined by the size of the observable universe, as you mentioned, and is known as the cosmic microwave background radiation. This background radiation is the remnants of the Big Bang and has a wavelength of about 1.9 mm.

However, there is no lower limit on the frequency of electromagnetic radiation. According to the Planck-Einstein relation, energy is directly proportional to frequency, meaning that as the frequency decreases, the energy of the radiation also decreases. As a result, the lower frequency limit is determined by the sensitivity of our detection equipment.

In terms of the Maxwell equations, there is no explicit limit on the frequency of electromagnetic radiation. These equations describe the behavior of electric and magnetic fields and do not set a limit on their frequency. However, at very high frequencies, there may be deviations from the classical behavior described by Maxwell's equations, and quantum effects may become more prominent.

Overall, while there is a maximum wavelength for electromagnetic radiation, there is no lower limit on its frequency. Our ability to detect and measure extremely low frequencies is constantly improving, and who knows, maybe one day we will be able to observe and study even lower frequencies of electromagnetic radiation!