If a star appears to move back and forth relative to other stars over a six-month period, thismotion is due to the star's:
A)transverse motion.
B)radial motion.
C)parallax shift.
D)Doppler shift.
E)true space motion.

Question

Quizplus · Accepted Answer

The back-and-forth motion of a star relative to other stars over a six-month period is known as parallax shift, which is caused by the Earth's orbital motion around the Sun. As the Earth orbits the Sun, the viewing angle of a nearby star appears to change, creating an apparent shift in position against the backdrop of more distant stars. The apparent back and forth motion of a star over a six-month period is due to the parallax shift caused by the Earth's motion around the Sun. As the Earth moves from one side of its orbit to the other, our vantage point of nearby stars changes, causing them to appear to shift position in the sky. This parallax shift is used to measure the distances to nearby stars.

If a Star Appears to Move Back and Forth Relative