Beyond gamma rays, the electromagnetic spectrum continues with even higher-energy radiation. The classification of electromagnetic radiation from lowest energy to highest energy is as follows:
Radio Waves → Microwaves → Infrared Radiation → Visible Light → Ultraviolet Radiation → X-Rays → Gamma Rays
While gamma rays have the highest energy among the electromagnetic waves that we are familiar with, there is no strict upper limit to the energy of electromagnetic radiation. However, as we move to higher energies beyond gamma rays, the distinction between electromagnetic radiation and other types of high-energy particles becomes less clear.
At extremely high energies, beyond the reach of current technology, there are theoretical predictions for even higher-energy radiation, such as "ultra-high-energy gamma rays" or "very high-energy gamma rays." These would have energies far beyond the gamma rays produced by nuclear processes or cosmic sources. However, detecting and studying such high-energy radiation poses significant challenges due to its rarity and interaction with the Earth's atmosphere.
Furthermore, at the highest energies, the distinction between electromagnetic radiation and cosmic rays becomes blurred. Cosmic rays are highly energetic particles, such as protons or atomic nuclei, that travel through space at relativistic speeds. They can have energies millions or billions of times higher than the highest-energy gamma rays observed.
In summary, while gamma rays represent the highest-energy electromagnetic radiation we commonly refer to, the electromagnetic spectrum theoretically extends to even higher energies, and beyond that, it transitions into the realm of cosmic rays.