Visual radiation is in the middle, with wavelengths that extend from 0.00004 centimeters for violet light to about 0.00007 centimeters for extreme red.These wavelengths are so short that astronomers use a small unit of distance, the "Angstrom" (A), which is 0.00000001 centimeters long.The most familiar is "reflection," in which light is bounced from a surface, the light coming off at the same angle at which it hits, resulting in your undistorted face looking back at you from a mirror. When it passes into a substance, it slows and can be bent, a common phenomenon called "refraction." The effect is easily seen when looking at something through water.
This site, closely coupled to The Natures of the Stars and The Hertzsprung- Russell (HR) Diagram, provides an introduction to the spectra of stars and allied celestial objects.
Here we examine the principal way in which astronomers have learned so much about the stars. Pass sunlight through a triangular prism or bounce it off the finely grooved surface of a compact audio disk and see it break merrily into a band of pure sparkling color, its "spectrum," familiar in the colors of a rainbow, in light glittering from newly fallen snow, in the rings and haloes around a partly- clouded Sun and Moon, in the flash of a cut diamond, and in so many other facets of nature.
A single gamma ray photon can carry the energy of over a million million million radio photons.
Light and its partners can be manipulated in a variety of ways.
Refracted light is therefore "dispersed" or spread out into its spectrum, creating a rainbow -- or the spectrum of a star.
Spectra can also be created by the interference of light waves, the phenomenon that makes the brightly colored patterns seen reflected from a compact audio disc and the halos often observed next to a bright, partly clouded Moon.
Turned to the sky and attached to a detector, the lens becomes an astronomical telescope.
(A curved mirror can create a similar image by reflection.) The speed of an electromagnetic wave in a medium depends on its wavelength.
Spectra are commonly seen reproduced either photographically or graphically.