What type of light is invisible to the naked eye?

Infrared light is a type of electromagnetic radiation that falls just beyond the visible spectrum of light, meaning it cannot be seen by the naked eye. It is primarily associated with the heat that we feel from the sun and from warm objects. While visible light enables us to see colors and objects around us, infrared light operates on a different wavelength, making it invisible but detectable by certain instruments. This characteristic is widely utilized in various applications, including night vision technology and thermal imaging.

The other types of light mentioned either fall within the visible spectrum (like visible light itself) or are also invisible but have different characteristics and uses, such as gamma rays and X-rays, which serve specific roles in medical and industrial applications.