While a star is being observed through a telescope, the visible light coming from the star shifts from red to blue.
which is true about this star? i know for sure it's either b or c
a.
the shortening of wavelengths indicates that the star is moving away from earth.
b.
the lengthening of wavelengths indicates that the star is moving toward earth.
c.
the lengthening of wavelengths indicates that the star is moving away from earth.
d.
the shortening of wavelengths indicates that the star is moving toward earth.