In 1675,Rømer measured the speed of light by
A) timing eclipses of Jupiter's satellites,which appeared to occur later when Earth was farther from Jupiter.
B) measuring how long it took the light from stars located at different distances to reach Earth.
C) reflecting light from a mirror rotating at a known speed and measuring the angle of deflection of the light beam.
D) opening a shutter on a lantern on a hilltop and measuring the time taken for light from an assistant's shuttered lantern to return.

Question

Quizplus · Accepted Answer

Rømer's method involved timing eclipses of Jupiter's satellites, which appeared to occur later when Earth was farther from Jupiter. This allowed him to calculate the time it took for light to travel from Jupiter to Earth, and therefore the speed of light.

In 1675,Rømer Measured the Speed of Light by