An observer located outside our Solar System, who monitors the velocity of our Sun over time, will find that its velocity varies by $\pm$12 m/s over a period of 12 years, because of:
A) Jupiter's gravitational pull
B) Earth's gravitational pull
C) variations in its brightness
D) convection on the Sun's surface
E) the sunspot cycle

Question

Quizplus · Accepted Answer

The gravitational pull of Jupiter causes the Sun to move slightly as they orbit around their common center of mass. This motion can be observed as a periodic variation in the Sun's velocity, which has a 12-year period, consistent with the orbital period of Jupiter. The other choices, such as Earth's gravitational pull or variations in brightness, do not have a significant effect on the Sun's velocity over such a long period of time. Convection and the sunspot cycle can cause short-term variations in the Sun's velocity, but not over a period of 12 years.

An Observer Located Outside Our Solar System, Who Monitors the Velocity