Answer:
What are Infrared Waves?
The electromagnetic spectrum contains many types of waves, one of which is infrared waves. Other electromagnetic waves include gamma rays, x-rays, ultraviolet, visible light, microwaves, and radio.
Infrared waves are electromagnetic radiation of a particular wavelength or color that we have named 'infrared.' They are between 700 nm (nanometers) and 1 mm. Note that 1 mm is equal to 1,000,000 nanometers. They are just beyond what our eyes can detect on the red side of the rainbow. William Herschel first discovered them around 1800.
We are surrounded by infrared every moment of every day. Warm objects, such as the human body, produce large amounts of infrared, and heat-sensitive CCTV cameras work by detecting these infrared waves. Half of the energy produced by the sun is infrared, so we are being bombarded by it constantly.
Remote Controls & Communications
The most common use of infrared in everyday life is remote controls. These work by sending pulses of infrared that spell out a message to an electronic device. This device could be a television, blu-ray player, or even a computer. Infrared can be used in a similar way for communication. By sending these same pulses through fiber-optic cables, transmitting audio to sound systems, or other data through fiber-optic high-speed Internet services.
Night Vision & Heat
Thermal imaging cameras use infrared to look at human body heat emissions, both for medical purposes and in night-vision cameras. They're often used in the study of animals, as security cameras, or in war.
Astronomy
Infrared astronomy has helped us make significant strides in our understanding of the universe. Astronomers can look at an area of the sky that is dark in the visual part of the electromagnetic spectrum but find the area is extremely active in the infrared. Most objects that have any significant heat produce infrared waves, but not everything is hot enough to light up.
There are some limitations with infrared astronomy - telescopes need to be placed at high altitudes or on hot-air balloons because the atmosphere absorbs a lot of infrared before it reaches the Earth's surface. The best way around this is to launch space telescopes, such as the Hubble Space Telescope, which was launched in 1990. Space telescopes have provided us with some wonderfully clear images because there are no atmospheric effects at all.
Objects that infrared astronomy has helped us detect include dark and cold dust clouds, protostars that aren't yet producing light, and planets that are hard to see in the visible part of the spectrum due to glare from nearby stars.
