Visible spectrum
hideThe visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nm. In terms of frequency, this corresponds to a band in the vicinity of 790–400 terahertz. A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum (see: luminosity function). The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish. Unsaturated colors such as pink, and purple colors such as magenta are absent, for example, because they can only be made by a mix of multiple wavelengths.
Visible wavelengths also pass through the "optical window," the region of the electromagnetic spectrum that passes largely unattenuated through the Earth's atmosphere. (Blue light scatters more than red light, which is why the sky appears blue.) The human eye's response is defined by subjective testing (see CIE), but atmospheric windows are defined by physical measurement.
The "visible window" is so called because it overlaps the human visible response spectrum. The near infrared (NIR) windows lie just out of human response window, and the Medium Wavelength IR (MWIR) and Long Wavelength or Far Infrared (LWIR or FIR) are far beyond the human response region.
Many species can see wavelengths that fall outside the "visible spectrum". Bees and many other insects can see light in the ultraviolet, which helps them find nectar in flowers. Plant species that depend on insect pollination may owe reproductive success to their appearance in ultraviolet light, rather than how colorful they appear to us. Birds too can see into the ultraviolet (300-400 nm), and some have sex-dependent markings on their plumage, which are only visible in the ultraviolet range.
For more information about Visible spectrum, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with visible light
Dark Matter in a Galaxy
Oct 30, 2009 |
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(PhysOrg.com) -- Stars, the most familiar objects in the night sky, make up only a tiny percentage of the total amount of matter in the universe -- about 2%.
Scientists Build First 'Frequency Comb' To Display Visible 'Teeth'
Oct 29, 2009 |
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(PhysOrg.com) -- Finally, an optical frequency comb that visibly lives up to its name. Scientists at the University of Konstanz in Germany and the National Institute of Standards and Technology in the U.S. ...
Chinese scientists create metamaterial black hole
Oct 16, 2009 |
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(PhysOrg.com) -- Two physicists in China have used metamaterials to create the first artificial electromagnetic black hole. The scientists, Qiang Cheng and Tie Jun Cui from the Southeast University in Nanjing, ...
Spot discovered on dwarf planet Haumea shows up red and rich with organics
Sep 16, 2009 |
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A dark red area discovered on dwarf planet Haumea appears to be richer in minerals and organic compounds than the surrounding icy surface. The discovery will be presented at the European Planetary Science ...
Bananas Gone Bad Glow Blue in UV-Light
Sep 09, 2009 |
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(PhysOrg.com) -- Nicholas Turro of Columbia University, Bernhard Krautler of the University of Innsbruck, Austria and their colleagues have found that, as chlorophyll ages and begins to disintegrate in banana ...
New nanolaser -- spaser -- key to future optical computers and technologies
Aug 16, 2009 |
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(PhysOrg.com) -- Because the new device, called a "spaser," is the first of its kind to emit visible light, it represents a critical component for possible future technologies based on "nanophotonic" circuitry, ...
Astronomer's new guide to the galaxy: Largest map of cold dust revealed
Jul 01, 2009 |
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This new guide for astronomers, known as the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) shows the Milky Way in submillimetre-wavelength light (between infrared light and radio waves). Images ...
New 'broadband' cloaking technology simple to manufacture
May 20, 2009 |
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(PhysOrg.com) -- Researchers have created a new type of invisibility cloak that is simpler than previous designs and works for all colors of the visible spectrum, making it possible to cloak larger objects ...
Transparent Carbon Nanotube Films Likely Successor to ITO for Commercial Applications
Nanotechnology / Nanomaterials
Apr 10, 2009 |
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(PhysOrg.com) -- Will the legacy of Nobel prize winner Richard Smalley finally be fulfilled? Ever since his pioneering work in the mid 1990's on the synthesis of carbon nanotubes, companies have been struggling ...
Astrophysicists explore a blazar
Mar 18, 2009 |
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An international team of astrophysicists using telescopes on the ground and in space have uncovered surprising changes in radiation emitted by an active galaxy. The picture that emerges from these first-ever ...
Galaxy Cores to Crash in a Few Million Years
Mar 16, 2009 |
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(PhysOrg.com) -- A new image from NASA's Spitzer Space Telescope offers a rare view of an imminent collision between the cores of two merging galaxies, each powered by a black hole with millions of times the ...
Will carbon nanotubes replace indium tin oxide?
Nanotechnology / Nanomaterials
Mar 09, 2009 |
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(PhysOrg.com) -- Up until now, George Grüner tells PhysOrg.com, most of the studies regarding the properties - and uses - of carbon nanotubes have been restricted to the visible spectral range. “We, however, were interested in the ...
Next generation cloaking device demonstrated
Jan 15, 2009 |
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A device that can bestow invisibility to an object by "cloaking" it from visual light is closer to reality. After being the first to demonstrate the feasibility of such a device by constructing a prototype ...
LEDs may help reduce skin wrinkles, researchers report
Oct 20, 2008 |
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Researchers in Germany are describing a potential alternative to Botox and cosmetic surgery for easing facial wrinkles. Their study, scheduled for the November 5 issue of ACS' Crystal Growth & Design report ...
Violent flickering in Black Holes
Oct 15, 2008 |
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(PhysOrg.com) -- Unique observations of the flickering light from the surroundings of two black holes provide new insights into the colossal energy that flows at their hearts. By mapping out how well the variations ...
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