Galileo Observed the Phenomenon of Solar Rotation in the Early

Multiple Choice

Galileo observed the phenomenon of solar rotation in the early 1600s by

A) noting the periodic (monthly) variation of auroral disturbances, or northern lights.
B) watching bright regions of hydrogen gas drift across the Sun.
C) measuring the motion of sunspots across the solar surface.
D) measuring the Doppler shift of hydrogen spectral lines from the east and west limbs of the Sun.