Why infrared

Infrared radiation IR is a type of radiant energy , with longer wavelengths than the visible light humans can see, but shorter wavelengths than radio waves. Its range extends from fairly small wavelengths near the color red, x10 -9 m , to nearly a millimeter, 3x10 -4 m. Even though infrared radiation cannot be seen by the human eye, it can definitely be felt. Infrared energy is felt as heat because it interacts with molecules by exciting them, causing them to move faster which increases the internal temperature of the object absorbing the infrared energy.

Although all wavelengths of radiant energy will heat surfaces that absorb them, infrared radiation is most common in daily life because of the "ordinary" objects that emit it as radiant heat see blackbody radiation and Wien's Law for more information on this. Read more about this imbalance here. IR radiation is one of the three ways heat is transferred from one place to another, the other two being convection and conduction. Everything with a temperature above around 5 degrees Kelvin minus degrees Fahrenheit or minus degrees Celsius emits IR radiation.

The sun gives off half of its total energy as IR, and much of the star's visible light is absorbed and re-emitted as IR, according to the University of Tennessee. Household appliances such as heat lamps and toasters use IR radiation to transmit heat, as do industrial heaters such as those used for drying and curing materials.

Incandescent bulbs convert only about 10 percent of their electrical energy input into visible light energy, while the other 90 percent is converted to infrared radiation, according to the Environmental Protection Agency. Infrared lasers can be used for point-to-point communications over distances of a few hundred meters or yards. The receiver converts the light pulses to electrical signals that instruct a microprocessor to carry out the programmed command. One of the most useful applications of the IR spectrum is in sensing and detection.

All objects on Earth emit IR radiation in the form of heat. This can be detected by electronic sensors, such as those used in night vision goggles and infrared cameras. A simple example of such a sensor is the bolometer, which consists of a telescope with a temperature-sensitive resistor, or thermistor, at its focal point, according to the University of California, Berkeley UCB. If a warm body comes into this instrument's field of view, the heat causes a detectable change in the voltage across the thermistor.

Night vision cameras use a more sophisticated version of a bolometer. These cameras typically contain charge-coupled device CCD imaging chips that are sensitive to IR light. A scientist used temperatures to determine which parts of the image were from clouds and which were land and sea. Based on these temperature differences, he colored each separately using colors, giving the image a realistic appearance.

Why use the infrared to image the Earth? While it is easier to distinguish clouds from land in the visible range, there is more detail in the clouds in the infrared. This is great for studying cloud structure.

For instance, note that darker clouds are warmer, while lighter clouds are cooler. Southeast of the Galapagos, just west of the coast of South America, there is a place where you can distinctly see multiple layers of clouds, with the warmer clouds at lower altitudes, closer to the ocean that's warming them.

We know, from looking at an infrared image of a cat, that many things emit infrared light. But many things also reflect infrared light, particularly near infrared light. Infrared Waves. Retrieved [insert date - e. Science Mission Directorate. National Aeronautics and Space Administration. What are Infrared Waves? LEFT: A typical television remote control uses infrared energy at a wavelength around nanometers.

While you cannot "see" the light emitting from a remote, some digitaland cell phone cameras are sensitive to that wavelength of radiation.

Try it out! RIGHT: Infrared lamps heat lamps often emit both visible and infrared energy atwavelengths between nm to nm in length. They can be used to heat bathroomsor keep food warm. Heat lamps can also keep small animals and reptiles warm oreven to keep eggs warm so they can hatch. When we look up at the constellation Orion, we see only the visible light. But NASA'sSpitzer space telescope was able to detect nearly 2, planet-forming disks in theOrion nebula by sensing the infrared glow of their warm dust.

Each disk has thepotential to form planets and its own solar system. Credit: Thomas Megeath Univ. Toledo et al.