infraroie

Infraroie, commonly known as infrared radiation, refers to a type of electromagnetic radiation with wavelengths longer than visible light but shorter than microwave radiation. It falls within the spectrum between approximately 700 nanometers and 1 millimeter, though definitions can vary depending on context. Infrared radiation is invisible to the human eye but can often be felt as heat, as it is absorbed by the skin and warms objects.

The term "infrared" originates from the Latin *infra*, meaning "below," and *red*, referring to its position just below the red end of the visible light spectrum. Infrared radiation is emitted by objects based on their temperature, following principles described by Planck’s law of black-body radiation. All objects with temperatures above absolute zero (0 Kelvin or -273.15°C) emit some form of infrared radiation, though cooler objects emit primarily at longer wavelengths.

Infrared technology has numerous practical applications. In astronomy, infrared telescopes observe celestial objects that emit heat, such as stars, galaxies, and even planets. In remote controls, infrared signals transmit data wirelessly between devices. Thermal imaging cameras detect infrared radiation to create images based on temperature differences, useful in military, medical, and building inspection fields. Additionally, infrared spectroscopy is a key analytical tool in chemistry for identifying molecular structures.

Infrared radiation is generally harmless to humans in low doses, but prolonged exposure to intense sources, such as industrial heaters or solar concentrators, can cause skin burns. Moderate exposure is typically safe, and infrared is even used therapeutically in physical therapy to relieve muscle pain and stiffness. However, high-intensity infrared, such as that from lasers, can pose risks and requires proper safety measures.