S tarlight ’ s S tory what can the light we see in the night sky tell us about the univesrse ? Griffin Rodgers a Visible light is a small band of wavelengths on this larger spectrum. Newton’s observations signified the beginning of serious scientific inquiry into the properties of light and color. In 1802, William Hyde Wallaston further examined prisms and discovered that the rainbow created by passing light through a prism had gaps or lines in it. He incorrectly concluded that the lines were the natural borders of colors. Nevertheless, this observation led to further inquiry into the properties of light and the light spectra. A few years later, Joseph Von Faunhofer expanded the study of light by studying the spectra of certain flames, the sun’s light, and light coming from stars in the night sky. In the mid-1800’s Gustav Kirchoff and Robert Bunsen examined and mapped the light spectrum emitted by the burning of certain elements, and they concluded that each element emits a specific spectrum. This chain of discoveries took place from the 1660’s through the 1820’s. An accurate description of how the properties of atoms and their electrons would cause the specific emission spectrums and lines on the sun’s light spectrum wouldn’t be found for another 50 years. Regardless, the examination of spectral lines became a tool for scientists which we now call spectroscopy. (Tyson, 2001) A few years after Kirchoff and Bunsen mapped their spectra, Christian Doppler began studying how the pitch of sound changes when the noise source is moving relative to the observer. He discovered that when the source of sound is coming towards the observer, the pitch of the sound is perceived to be higher by the observer. Conversely, if the source is moving away from the observer, the pitch is perceived to be lower by the observer. He “So long as humans have not achieved intergalactic transportation, the only way to study the composition of far-away exoplanets or stars is through the light that they emit.” B erkeley S cientific J ournal •C olors • F all 2012 • V olume 17 • I ssue 1 • 1 B S J stronomers are constantly challenged with the task of studying objects that exist many light years away. Typically, the only information an astronomer has about an object is the light coming from that object. As a result, astronomers have used extensive knowledge of light’s properties to develop clever methods for studying the light emitted from distant celestial bodies. Recent technology has made these methods even more useful. Knowledge of light’s properties equips astronomers with certain tools that assist them in their search for answers. Two of these tools, spectroscopy and the Doppler Effect, rely on simple properties of the light spectrum—often in the visible light range—as the basis for explaining many perplexing phenomena that the universe presents. Spectroscopy is the study of the spectrum of light in order to understand properties of the source of the light. It developed as a tool for astronomers through the slow accretion of knowledge about light’s behavior. For many years it was known that light would produce a rainbow when passed through a prism. Isaac Newton further examined light’s properties and interactions with prisms in the 1660’s. He discovered the prismatic effects of light; as white light (like that coming from the sun) passes through a prism, it exits the prism as a rainbow. Placing a second prism in front of the rainbow of light which exited the first prism then converts the rainbow back into white light. The resulting rainbow was considered a spectrum of light. A spectrum is now known more generally as certain wavelengths on the electromagnetic radiation.