The above visual wavelength image of spectra (right panel) taken from a spiral galaxy (left panel) shows an emission line that is__________ on the side that is rotating away and an emission line that is ___________ on the side that is rotating towards us.
A) redshifted, redshifted
B) blueshifted, blueshifted
C) redshifted, blueshifted
D) blueshifted, redshifted

Question

The above visual wavelength image of spectra (right panel) taken from a spiral galaxy (left panel) shows an emission line that is__________ on the side that is rotating away and an emission line that is ___________ on the side that is rotating towards us.
A) redshifted, redshifted 
B) blueshifted, blueshifted 
C) redshifted, blueshifted 
D) blueshifted, redshifted

Quizplus · Accepted Answer

The emission line on the side that is rotating away is redshifted, while the emission line on the side that is rotating towards us is blueshifted. This is due to the Doppler effect, where the wavelength of light emitted from an object appears shorter (blueshifted) if the object is moving towards us and longer (redshifted) if the object is moving away from us.

The Above Visual Wavelength Image of Spectra (Right Panel) Taken