Final answer:
The missing dark lines in a star's spectrum indicate that certain wavelengths are absorbed by elements in the star's atmosphere, not that it is made of dark matter or that it is not emitting light. This phenomenon helps scientists determine the star's chemical composition.
Step-by-step explanation:
If you observe a spectrum of a distant star that shows a rainbow of colors with missing, dark lines, it could mean that the star's atmosphere absorbs certain wavelengths of light. Each element present in the star's atmosphere absorbs light at specific wavelengths, resulting in a spectrum with characteristic absorption lines. These lines provide valuable information about the chemical composition of the star's atmosphere.
The missing dark lines do not imply that the star is made of dark matter or that the star is not emitting light. While dark matter does not emit or absorb light in ways that we can currently detect, this is not related to the absorption lines seen in a star's spectrum. Similarly, the Doppler effect can shift the position of these lines if the star is moving towards or away from us (redshift or blueshift), but it does not remove lines from the spectrum.