Lining Up Future Discoveries

This rainbow of colors is actually a powerful astronomical tool: the spectrum of the star Arcturus. Astronomers created the image by splitting the star's light into its individual wavelength or colors. What makes the spectrum so powerful is the series of dark lines across the bands of color. These lines are produced by chemical elements in the star's upper atmosphere. They reveal the star's composition, rotation rate, motion through space, and much more. Two scientists discovered this trick of starlight 150 years ago. [N.A.Sharp/NOAO/AURA/NSF]