Visible Light | Science Mission Directorate

Illustration of a visible wave on the electromagnetic spectrum

What is the visible light spectrum?

The visible light spectrum is the segment of the electromagnetic spectrum that the human eye can view. More simply, this roll of wavelengths is called visible light. typically, the homo eye can detect wavelengths from 380 to 700 nanometers.

WAVELENGTHS OF VISIBLE LIGHT

All electromagnetic radiation is light, but we can alone see a humble part of this radiation—the part we call visible light. conic cells in our eyes act as receivers tuned to the wavelengths in this minute band of the spectrum. other portions of the spectrum have wavelengths excessively large or excessively little and energetic for the biological limitations of our perception .
As the full spectrum of visible light travels through a prism, the wavelength separate into the colors of the rainbow because each color is a different wavelength. Violet has the shortest wavelength, at around 380 nanometers, and loss has the longest wavelength, at around 700 nanometers .
Left: A 3D illustration of 2 prisms. As light shine through one, it is refracted into the colors of the rainbow. As the full spectrum of light - the rainbow - travels through the second prism, the waves are recombined into white light.  Right: illustration of each wavelength in the spectrum (Left) Isaac Newton ‘s experiment in 1665 showed that a prism bends visible light andthat each color refracts at a slenderly different angle depending on the wavelength of the color.Credit : Troy Benesch. (Right) Each color in a rainbow corresponds to a unlike wavelength of electromagnetic spectrum .

 

THE SUN’S CORONA

The Sun is the prevailing source for visible-light waves our eyes receive. The outer-most level of the Sun ‘s atmosphere, the corona discharge, can be seen in visible light. But it is thus faint it can not not be seen except during a entire solar eclipse because the bright photosphere overwhelms it. The photograph below was taken during a entire overshadow of the Sun where the photosphere and chromosphere are about completely blocked by the moon. The sharpen patterns—coronal streamers—around the Sun are formed by the outward menstruation of plasma that is shaped by magnetic field lines extending millions of miles into space .
A photograph of a solar eclipse revealing the dramatic coronal streamers that are normally too faint to see over the intense light of the sun's chromosphere. credit : © 2008 Miloslav Druckmüller, Martin Dietzel, Peter Aniol, Vojtech Rušin

 

COLOR AND TEMPERATURE

As objects grow hot, they radiate energy dominated by shorter wavelengths, changing color before our eyes. A fire on a blow common mullein shifts from red to bluish in semblance as it is adjusted to burn hot. In the like means, the semblance of stars tells scientists about their temperature .
Our Sun produces more jaundiced lighter than any other color because its surface temperature is 5,500°C. If the Sun ‘s surface were cooler—say 3,000°C—it would look red, like the ace Betelgeuse. If the Sun were hotter—say, 12,000°C—it would look blue sky, like the ace Rigel .
Isaac Newton ‘s experiment in 1665 showed that a prism bends visible light and that each color refracts at a slenderly different angle depending on the wavelength of the coloring material .
An image of the surface of the Sun appearing warm yellow. A temperature gauge on the left side shows the hotter star Rigel as blue and the cooler star Betelgeuse as red. credit : Jenny Mottar ; Image Courtesy of SOHO/consortium

a true-color composite of a crater on Mars that looks ruddy brown in color. The High Resolution Imaging Science Experiment ( HiRISE ) camera on dining table the MarsReconnaissance Orbiter ( MRO ) captured this spectacular visible light picture of Victoria Crater.Credit : NASA/JPL/University of Arizona

 

SPECTRA AND SPECTRAL SIGNATURES

airless examen of the visible-light spectrum from our Sun and other stars reveals a model of dark lines—called preoccupation lines. These patterns can provide significant scientific clues that reveal shroud properties of objects throughout the universe. certain elements in the Sun ‘s air absorb certain colors of light. These patterns of lines within spectrum act like fingerprints for atoms and molecules. Looking at the Sun ‘s spectrum, for exemplar, the fingerprints for elements are clear to those knowing about those patterns .
An image of the full spectrum of visible light - the rainbow - with dark lines appearing in the red, orange-yellow, and green-blue areas of the spectrum. These dark lines indicate that these specific wavelengths are missing and can be aligned to the elements that absorb these specific wavelengths - hydrogen, sodium, and magnesium. Patterns are besides discernible in a graph of an object ‘s coefficient of reflection. Elements, molecules, and evening cell structures have unique signatures of coefficient of reflection. A graph of an object ‘s coefficient of reflection across a spectrum is called a spectral signature. spectral signatures of different Earth features within the visible light spectrum ARE shown below .
A graph showing wavelengths in nanometers on the x-axis and percent reflectance on the y-axis. Snow, ice and clouds show a high reflectance across all wavelengths. Dry soil, wet soil, turbid water and clear water all seem to reflect similar values in the blue and green wavelengths, but have very different value closer to red and infrared where soils reflect more than water. Vegetation reflects more in the green and infrared than in the blue and red. citation : Jeannie Allen

 

ACTIVE REMOTE SENSING—ALTIMETRY

Laser altimetry is an exercise of active remote control sensing using visible light. NASA ‘s Geoscience Laser Altimeter System ( GLAS ) instrument onboard the Ice, Cloud, and land Elevation Satellite ( ICESat ) enabled scientists to calculate the aggrandizement of Earth ‘s polar methamphetamine sheets using lasers and accessory data. Changes in elevation over time avail to estimate variations in the sum of water stored as ice on our planet. The image below shows acme data over the West Antarctic Ice Streams .
Laser altimeters can besides make alone measurements of the heights and characteristics of clouds, adenine well as the clear and structure of the vegetation canopy of forests. They can besides sense the distribution of aerosols from sources such as dust storms and forest fires .
An oblique image of ice streams at the edge of Antarctica is shown here with a super-imposed vertical profile revealing the height of ice in and around the streams. recognition : NASA/Goddard Space Flight Center

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Citation
APA

National Aeronautics and Space Administration, Science Mission Directorate. ( 2010 ). visible Light. Retrieved [ cut-in date – e.g. August 10, 2016 ], from NASA Science web site : hypertext transfer protocol : //science.nasa.gov/ems/09_visiblelight

MLA

Science Mission Directorate. “ visible Light ” NASA Science. 2010. National Aeronautics and Space Administration. [ slip in date – e.g. 10 Aug. 2016 ] hypertext transfer protocol : //science.nasa.gov/ems/09_visiblelight

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