You can find infrared (IR) light just past visible red light in the electromagnetic spectrum. Crucially, because almost everything gives off infrared light as heat, IR light is emitted by a vast array of objects around you.
Understanding Infrared Light
Infrared light is a type of electromagnetic radiation, similar to visible light, radio waves, or X-rays. The key difference lies in its wavelength. As the reference notes, it is located on the spectrum just past visible red light. This position means its wavelengths are longer than visible red light and shorter than microwaves.
Unlike visible light, which allows us to see the world, infrared light is not visible to the human eye. Our eyes are simply not equipped to detect these wavelengths. However, while invisible to us, IR light is detectable using special equipment.
Sources of Infrared Light
One of the most fundamental properties of infrared light, highlighted by the reference, is that almost everything gives off infrared light as heat. This means that any object that has a temperature above absolute zero (-273.15°C or 0 Kelvin) emits some amount of infrared radiation. The warmer an object is, the more intense the infrared radiation it emits.
Common sources include:
- The Sun: A primary source of natural infrared radiation, providing much of Earth's warmth.
- Fire and Heating Elements: Obvious sources of heat, emitting significant IR light.
- Living Beings: Humans, animals, and even plants constantly emit infrared radiation as body heat.
- Electrical Appliances: Many devices generate heat during operation, giving off IR light (e.g., ovens, computers, motors).
- The Earth Itself: The ground, water, and atmosphere absorb energy and re-emit it as infrared radiation.
Because infrared light is emitted based on heat, it does not depend on visible light being present. As the reference states, IR light can be detected in dark or obscure conditions, making it useful for night vision and thermal imaging.
Detecting and Utilizing Infrared Light
While we can't see it, infrared light is widely used in technology. Special sensors and cameras, often called thermal cameras, are designed to detect and capture infrared radiation, converting it into images or data that we can interpret.
Applications include:
- Thermal Imaging: Used in security (night vision), building inspection (finding heat leaks), medicine (detecting fevers), and environmental monitoring.
- Remote Controls: Many consumer electronics use infrared signals to communicate between the remote and the device.
- Heating: Infrared lamps are used for heating spaces or specific objects.
- Communication: Short-range data transfer (like older phone IR ports) and fiber optic communication utilize infrared light.
- Astronomy: Telescopes designed to detect infrared light can observe objects in the universe that are otherwise hidden by dust or are too cool to emit much visible light.
In summary, infrared light is a form of radiant energy that is constantly being emitted by anything with heat. You can find it emanating from natural sources like the sun and living beings, as well as from countless artificial objects that generate warmth.
