Difference between revisions of "Light beyond the visible"

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''Ruthlessly copied from [http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html What is infrared?] from the [http://coolcosmos.ipac.caltech.edu Cool Cosmos] site.''
 
  
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=Most coherent, developed, tested materials=
  
Our eyes are detectors which are designed to detect visible light waves (or visible radiation). Visible light is one of the few types of radiation that can penetrate our atmosphere and be detected on the Earth's surface. There are forms of light (or radiation) which we cannot see. Actually we can only see a very small part of the entire range of radiation called the [http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/emspec.html electromagnetic spectrum].
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* [https://www.youtube.com/watch?v=3fMmZ4nMV8Q Movie (7:42) on IR light] (by Dr. Luisa Rebull, 2015)
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* [https://www.youtube.com/watch?v=B4tvy1XA_SA Another movie (11:06) on multi-wavelength light] (by Dr. Luisa Rebull, 2015)
  
[[Image: emspec.jpg]]
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*[http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html What is infrared?] from the [http://coolcosmos.ipac.caltech.edu Cool Cosmos] site.
  
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*[http://coolcosmos.ipac.caltech.edu Cool Cosmos], the main IPAC education and public outreach server, with TONS of information about infrared (in English and Spanish!).  Just some of the highlights from this site include the following:
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**[http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html What is infrared?]
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**[https://coolcosmos.ipac.caltech.edu/page/lesson_plans IR Lesson Plans]
  
The electromagnetic spectrum includes gamma rays, X-rays, ultraviolet, visible, infrared, microwaves, and radio waves. The only difference between these different types of radiation is their wavelength or frequency. Wavelength increases and frequency (as well as energy and temperature) decreases from gamma rays to radio waves. All of these forms of radiation travel at the speed of light (186,000 miles or 300,000,000 meters per second in a vacuum). In addition to visible light, radio, some infrared and a very small amount of ultraviolet radiation also reaches the Earth's surface from space. Fortunately for us, our atmosphere blocks out the rest, much of which is very hazardous, if not deadly, for life on Earth.
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=Other links of interest=
 
 
 
 
Infrared radiation lies between the visible and microwave portions of the electromagnetic spectrum. Infrared waves have wavelengths longer than visible and shorter than microwaves, and have frequencies which are lower than visible and higher than microwaves. Infrared is broken into three categories: near, mid and far-infrared. Near-infrared refers to the part of the infrared spectrum that is closest to visible light and far-infrared refers to the part that is closer to the microwave region. Mid-infrared is the region between these two.
 
 
 
  
The primary source of infrared radiation is heat or thermal radiation. This is the radiation produced by the motion of atoms and molecules in an object. The higher the temperature, the more the atoms and molecules move and the more infrared radiation they produce. Any object which has a temperature i.e. anything above absolute zero (-459.67 degrees Fahrenheit or -273.15 degrees Celsius or 0 degrees Kelvin), radiates in the infrared. Absolute zero is the temperature at which all atomic and molecular motion ceases. 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. The [http://coolcosmos.ipac.caltech.edu/image_galleries/our_ir_world_gallery.html Infrared World Gallery] has many pictures of people and things in visible and infrared light so that you can see how much infrared is coming from various objects (and parts of objects). 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). Infrared images give us different views of familiar things as well as information that we could not get from a visible light picture.
 
 
=Other links of interest=
 
*[http://coolcosmos.ipac.caltech.edu Cool Cosmos], the main IPAC education and public outreach server, with TONS of information about infrared (in English and Spanish!).  Just some of the highlights from this site include the following:
 
**[http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html What is infrared?]
 
**[http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/ IR tutorial]
 
**[http://coolcosmos.ipac.caltech.edu/cosmic_classroom/classroom_activities/index.html Classroom activities]
 
**[http://coolcosmos.ipac.caltech.edu/image_galleries/our_ir_world_gallery.html Infrared world gallery] (people, things, and places in optical and infrared)
 
*[http://coolcosmos.ipac.caltech.edu/videos/more_than_your/index.html Video entitled "Infrared: More than Your Eyes can see"]
 
*http://chandra.si.edu/resources/flash/telescopes_light.html Flash resource from Chandra
 
  
=[[I'm ready to go on to "Advanced" Topics in Infrared]]=
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*[http://chandra.si.edu/resources/flash/telescopes_light.html Light resource from Chandra]
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*[https://science.nasa.gov/learners/wavelength NASA wavelength] has a HUGE number of developed, tested, vetted lessons. Search for light-related lesson plans here.
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*[http://www.griffithobservatory.org/exhibits/halloftheeye_beyondthevisible.html Griffith Observatory] exhibit on light beyond the visible
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*[http://hubble.stsci.edu/webb_telescope/science_on_the_edge/beyond_the_visible/ Hubble Space Telescope] site on light beyond the visible
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*[https://en.wikipedia.org/wiki/Electromagnetic_radiation Wikipedia on electromagnetic radiation]
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*[https://www.khanacademy.org/science/cosmology-and-astronomy/universe-scale-topic/light-fundamental-forces/v/introduction-to-light Khan Academy on light]

Latest revision as of 20:12, 29 July 2020

Most coherent, developed, tested materials

  • Cool Cosmos, the main IPAC education and public outreach server, with TONS of information about infrared (in English and Spanish!). Just some of the highlights from this site include the following:

Other links of interest