Imagine an astronomer who has just used a spectroscope to measure the emission lines of radiation from a distant galaxy. When she looks at the emission lines of hydrogen, she notes that all of the lines measured are shifted from their expected positions toward the red end of the spectrum. Is the galaxy moving toward the astronomer or away from her?

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The Answer of Imagine an astronomer who has just used a spectroscope to measure the emission lines of radiation from a distant galaxy. When she looks at the emission lines of hydrogen, she notes that all of the lines measured are shifted from their expected positions toward the red end of the spectrum. Is the galaxy moving toward the astronomer or away from her?

Imagine an Astronomer Who Has Just Used a Spectroscope to Measure