Question

1. an astronomer observes light from a distant galaxy. the astronomer notices the absorption lines of the emission spectra for hydrogen are shifted toward the red end of the spectrum compared to the sun. which conclusion is best supported by this observation? a the galaxy is moving toward earth because the light wavelengths are shorter. b the galaxy is moving toward earth because the light wavelengths are longer. c the galaxy is moving away from earth because the light wavelengths are shorter. d the galaxy is moving away from earth because the light wavelengths are longer. a b c d

Explanation:

Redshift describes the phenomenon where light from an object moving away from an observer has its wavelengths stretched, shifting toward the red (longer wavelength) end of the spectrum. This matches the observation of hydrogen absorption lines shifted red compared to the Sun. Options A and B incorrectly state the galaxy is moving toward Earth (which would cause blueshift, shorter wavelengths), and option C incorrectly links redshift to shorter wavelengths.

Answer:

D. The galaxy is moving away from Earth because the light wavelengths are longer.