3. Stellar Spectroscopy​

How can we know what a star billions of miles away is made of, how hot it is, or how fast it’s moving toward or away from us? We can’t visit a star to collect a sample, but we don't have to—stars send their information directly to us encoded in their light.

By passing starlight through a prism or diffraction grating, astronomers split light into its component colors, producing a spectrum. The dark absorption lines imprinted across these spectra act like a unique chemical fingerprint for every star.

Stellar spectroscopy is the study of these spectral signatures. Watch the video below to explore how analyzing starlight allows us to decode a star's surface temperature, chemical composition, atmospheric density, and velocity across the cosmos.​