Answer:
Blue shift is the complete opposite of red shift, meaning that instead of moving farther apart, they move closer together. This is related to blue wavelengths in the visible light spectrum because they are closer together.
Redshift and blueshift describe how light shifts toward shorter or longer wavelengths as objects in space (such as stars or galaxies) move closer or farther away from us. The concept is key to charting the universe's expansion
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