Which phenomenon can be analyzed using spectroscopy?

Spectroscopy is a powerful technique used to analyze light emitted, absorbed, or scattered by materials, making it particularly valuable in the field of astronomy. The correct answer relates directly to how spectroscopy can provide detailed information about celestial objects. When light from these objects is directed through a spectrograph, it is dispersed into its component colors (spectrum), revealing critical information such as chemical composition, temperature, density, mass, distance, luminosity, and relative motion.

By studying the spectrum of light emitted from a star or galaxy, astronomers can identify which elements are present, infer physical conditions, and understand various processes occurring within and around these objects. This process is essential for constructing a detailed picture of the universe and its components.

The other options touch on important astronomical phenomena, but they do not relate directly to the analysis capabilities provided by spectroscopy. For instance, while the rotation speed of galaxies can be inferred through other methods, such as the Doppler effect, and background radiation can be studied using different observational techniques, it is the light from celestial objects that directly interacts with spectroscopy to yield measurable physical parameters. Similarly, gravitational waves from neutron stars are detected through specialized instruments and methods focused on measuring distortions in spacetime rather than analyzing light.