Infrared light lies between the visible and microwave portions of the electromagnetic spectrum. Infrared light has a range of wavelengths, just like visible light has wavelengths that range from red light to violet. "Near infrared" light is closest in wavelength to visible light and "far infrared" is closer to the microwave region of the electromagnetic spectrum. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic.
Far infrared waves are thermal. In other words, we experience this type of infrared radiation every day in the form of heat! The heat that we feel from sunlight, a fire, a radiator or a warm sidewalk is infrared. The temperature-sensitive nerve endings in our skin can detect the difference between inside body temperature and outside skin temperature.
Infrared light is even used to heat food sometimes - special lamps that emit thermal infrared waves are often used in fast food restaurants!
Shorter, near infrared waves are not hot at all - in fact you cannot even feel them. These shorter wavelengths are the ones used by your TV's remote control.
Since the primary source of infrared radiation is heat or thermal radiation, any object which has a temperature radiates in the infrared. Even objects that we think of as being very cold, such as an ice cube, emit infrared. When an object is not quite hot enough to radiate visible light, it will emit most of its energy in the infrared. For example, hot charcoal may not give off light but it does emit infrared radiation which we feel as heat. The warmer the object, the more infrared radiation it emits.
Humans, at normal body temperature, radiate most strongly in the infrared at a wavelength of about 10 microns. (A micron is the term commonly used in astronomy for a micrometer or one millionth of a meter.)
Humans may not be able to see infrared light, but did you know that snakes in the pit viper family, like rattlesnakes, have sensory "pits", which are used to image infrared light? This allows the snake to detect warm blooded animals, even in dark burrows! Snakes with 2 sensory pits are even thought to have some depth perception in the infrared!
Many things besides people and animals emit infrared light - the Earth, the Sun, and far away things like stars and galaxies do also! For a view from Earth orbit, whether we are looking out into space or down at Earth, we can use instruments on board satellites.
Satellites like GOES 6 and Landsat 7 look at the Earth. Special sensors, like those aboard the Landsat 7 satellite, record data about the amount of infrared light reflected or emitted from the Earth's surface.
Landsat 7
Other satellites, like the Infrared Astronomy Satellite (IRAS) look up into space and measure the infrared light coming from things like large clouds of dust and gas, stars, and galaxies!
for more info check the site
http://imagers.gsfc.nasa.gov/ems/infrared.html
2007-01-21 12:02:19
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answer #1
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answered by jamaica 5
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Some flowers have zones on them which emit infrared, this zone, sometimes called a nectar zone I believe can be seen by certain pollinators. insects like bees and butterflies are able to see these zones on the inside of the petals and it indicates to them where they must land....this increases the efficiency of feeding in the insect and increases the chance for successful pollination for the plant!
pretty cool
2007-01-21 12:07:35
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answer #2
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answered by Anonymous
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