What is the primary role of spectroscopy in astronomy?

The primary role of spectroscopy in astronomy is to analyze the light spectrum from celestial objects. Spectroscopy involves measuring the intensity of light across different wavelengths, which allows astronomers to determine various properties of stars and other celestial bodies. By examining the spectrum, scientists can identify the composition, temperature, density, mass, distance, luminosity, and relative motion of these objects.

Through the study of spectral lines—specific wavelengths where light is absorbed or emitted—astronomers can discern which elements are present in a star or galaxy. This process can reveal information about chemical compositions, physical conditions, and even the velocities of objects through the Doppler effect. The data obtained from spectroscopy are critical for understanding the physical processes occurring within stars and other celestial phenomena.

The other options involve different fields of study or techniques. Measuring the speed of celestial objects can be accomplished through methods such as Doppler shifts, while mapping the surfaces of distant planets typically involves imaging techniques rather than spectroscopy. Detecting black holes in galaxies often relies on observing the effects of their gravity on surrounding matter, rather than direct spectral analysis. Thus, the role of spectroscopy is central to unraveling the complexities of the universe through light analysis.