We know that just by studying the spectrum an astronomer can tell you what a star billions of miles away is made of and the elements present, take the star’s temperature, figure out how fast it is moving, a on s towards lets of the into which white light IS broken up when it is bent, as when it goes through a prism. All across the spectrum, in addition to the shadings of color, there are hundreds of parallel lines. They are known as Fraunhofer lines, in honor of their discoverer.

Each chemical element in a gaseous or vapor state has its own pattern of lines occupying its own place in the spectrum. The lines stand for the colors taken up from the light by the element when it is heated so that it glows. This means that a scientist can find out what materials are present in any substance, no matter how far removed. Each element makes its own “dark line” or absorption spectrum, different from those of any other element. By simply comparing the spectrum of a material being studied with the spectra of elements known in the laboratory, the physicist can tell what it is. In other words, each element leaves its fingerprint in light patterns.

Since the temperature causes an element’s line positions to change in the spectrum, astronomers can tell a great deal about the temperature Of stars billions of miles away. When a star is moving toward us, lines in the spectrum are shifted toward the violet end of the spectrum. When a star is moving away, the lines are shifted toward the red end of the band. From the amount of shift or displacement, scientists calculate that some stars are hurtling through space at the rate of 150 miles per second!