# How short can electromagnetic radiation become? Shorter than gamma rays?

• Doug1943
In summary: But as I understand it, there is a limit to how small a wavelength can be and that limit is determined by the Planck length. From a practical standpoint, gamma rays are the shortest known wavelengths of electromagnetic radiation, but theoretically, there could be waves with even shorter wavelengths.
Doug1943
is there some physical limit on the wavelength of electromagnetic radiation? Can there be radiation shorter than gamma rays?

No, because gamma has no lower bound on the wavelength. If it's shorter than X-rays, it's called gamma rays. Just as everything at the other end of the spectrum is called "radio waves" and there's no limit on how long those wavelengths can be. They're still called "radio".

There is no known limit on how short the wavelength of an EM wave can become. Everything past a certain frequency is either x-rays (if they originate from outside an atomic nucleus) or gamma rays (if they originate from the decay of an atomic nucleus).

Moderator's note: Moved thread to Classical Physics forum.

The limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length (1.616255(18)×10−35 m)
From https://en.wikipedia.org/wiki/Electromagnetic_spectrum
which cites Bakshi, U. A.; Godse, A. P. (2009). Basic Electronics Engineering. Technical Publications. pp. 8–10

Klystron
The continuity of the electromagnetic spectrum may be one of the most beautiful discoveries in physics. From the same source as above:
Note that there are no precisely defined boundaries between the bands of the electromagnetic spectrum; rather they fade into each other like the bands in a rainbow (which is the sub-spectrum of visible light).
Practical boundaries arise from technology. We can ask given current technology, what is the highest frequency -- shortest wavelength signal -- human devices can generate? Or that we can detect and at what energy?

davenn
Klystron said:
The continuity of the electromagnetic spectrum may be one of the most beautiful discoveries in physics. From the same source as above:

Practical boundaries arise from technology. We can ask given current technology, what is the highest frequency -- shortest wavelength signal -- human devices can generate? Or that we can detect and at what energy?
This assumes that human measurement is a requirement. I think the OP probably had in mind processes taking place in conditions that are too extreme to allow measurement. This takes us into the sort of situations where String Theory could be tested and beyond and we don't yet have the ability to go there.

Klystron

## 1. How is electromagnetic radiation measured?

Electromagnetic radiation is measured by its wavelength or frequency. Wavelength is the distance between two consecutive peaks or troughs of a wave, while frequency is the number of waves that pass a given point in one second.

## 2. What is the shortest wavelength of electromagnetic radiation?

The shortest wavelength of electromagnetic radiation is the Planck length, which is approximately 1.616 x 10^-35 meters. This is considered the smallest possible unit of length in the universe.

## 3. Can electromagnetic radiation be shorter than gamma rays?

Yes, electromagnetic radiation can be shorter than gamma rays. This is known as "hard" or "high-energy" gamma rays, which have shorter wavelengths and higher frequencies than regular gamma rays.

## 4. How are gamma rays different from other types of electromagnetic radiation?

Gamma rays are the highest energy form of electromagnetic radiation and have the shortest wavelengths and highest frequencies. They are typically produced by nuclear reactions or high-energy processes in outer space, such as supernovas.

## 5. What are the potential applications of shorter electromagnetic radiation?

Shorter electromagnetic radiation has potential applications in fields such as medical imaging, where higher energy radiation can be used to produce clearer images. It can also be used in scientific research to study the properties of matter at a smaller scale.

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