Spectroscopic binaries are star systems that consist of two stars orbiting each other, which are too close together to be seen separately through a telescope. Instead, astronomers detect them by observing the light they emit. As the stars move in their orbits, their light shifts in wavelength due to the Doppler effect, creating patterns in their spectra that reveal their presence. By studying these spectral patterns, scientists can determine important information about the stars, such as their masses, distances, and orbital periods. This method is crucial for understanding stellar evolution and the dynamics of systems like the Milky Way and other galaxies.