Suppose that you measure the light of a star between 640 and 680 nm and you get a very strong peak around 650 nm. what can you s

The star is moving away from our planet. To elaborate on the Doppler shift: This phenomenon, related to the Doppler effect, is the variation in the perceived frequency or wavelength (color) of a wave when the source of the waves and the observer are in motion relative to one another. Consequently, it can be inferred that as an object recedes, it exhibits more redshift in its spectrum. For instance, when a star moves away, its spectral lines shift towards the red end of the spectrum, whereas if it approaches Earth, the spectral lines move towards blue. Given that the peak wavelength is roughly 650 nm—which is associated with red—it can be concluded that the star is indeed moving away from Earth.