lähisäteilyä

Lähisäteilyä, meaning "near radiation" in Finnish, refers to electromagnetic radiation with wavelengths longer than ultraviolet light and shorter than microwaves. This spectral region is often considered to encompass infrared, visible light, and sometimes even the very short wavelength end of radio waves. However, in many contexts, especially in older literature or when discussing specific applications, lähisäteilyä primarily focuses on the infrared and visible light portions of the spectrum.

Infrared radiation, a significant component of lähisäteilyä, is associated with heat. All objects with a temperature above absolute zero emit infrared radiation. This radiation is invisible to the human eye but can be detected by specialized sensors and felt as warmth. Applications range from thermal imaging and remote controls to heating systems.

Visible light, the portion of lähisäteilyä that humans can perceive, is responsible for our sense of sight. It comprises the colors of the rainbow, from violet to red, each corresponding to a different wavelength. Visible light is crucial for processes like photosynthesis in plants and is the basis of all visual phenomena.

The term lähisäteilyä is not as commonly used in international scientific literature as specific terms like infrared or visible light. Its usage is more prevalent in Finnish-speaking scientific or technical contexts, often serving as a convenient umbrella term for these related forms of electromagnetic radiation. The precise boundaries of what is included under lähisäteilyä can sometimes vary depending on the specific field or publication.