The spectrum of a star shows an equivalent set of dark absorption lines to those of the Sun,with one exception: Every line appears at a slightly longer wavelength,shifted toward the red end of the spectrum.What conclusion can be drawn from this observation?
A) The star is moving rapidly toward Earth.
B) A cloud of dust surrounds the star and absorbs the light.
C) The star is moving rapidly away from Earth.
D) The temperature of the star's surface is higher than that of the Sun.

Question

Quizplus · Accepted Answer

The shift of the absorption lines toward the red end of the spectrum is known as a redshift, which occurs when an object is moving away from the observer. This phenomenon is a result of the Doppler effect, where the wavelength of light appears stretched or compressed depending on the relative motion of the source and observer. Therefore, the observation suggests that the star is moving rapidly away from the Earth.

The Spectrum of a Star Shows an Equivalent Set of Dark