Here's why:

* Electromagnetic Spectrum: The electromagnetic spectrum is a range of all types of electromagnetic radiation, ordered by wavelength (or frequency).

* Wavelength and Frequency: Wavelength and frequency are inversely proportional. This means that a longer wavelength corresponds to a lower frequency, and vice versa.

* Gamma Rays: Gamma rays have the highest frequencies and therefore the shortest wavelengths within the electromagnetic spectrum. They are highly energetic and often associated with nuclear processes.

Here's a simplified order of electromagnetic radiation from longest wavelength to shortest wavelength:

1. Radio waves

2. Microwaves

3. Infrared radiation

4. Visible light

5. Ultraviolet radiation

6. X-rays

7. Gamma rays