Steller Guide to the Universe
By: Cameron Rawls, Samantha Benner and Megan Murnick
How can this help astronomers?
Knowing which elements are in the stars is helpful because the spectroscopy changes when the stars are moving towards or away from the earth. The wavelengths become shorter when the stars move closer to the earth (the bands move towards blue on the spectrum) and the wavelengths become longer when the stars move away from the earth (the bands move towards the red on the spectrum). This is known as the Doppler effect.
This picture displays that the placement of the bands in the spectrum are the same distance apart, so it can still show what element it is. All of the lines are shifted to the left, meaning that the wavelengths are becoming shorter, showing that its moving closer to the earth.