Observers in a distant solar system are watching our Sun and using the radial-velocity method to try to determine whether the Sun has planets.Because of the gravitational pull of Jupiter,the observers see the Sun's spectrum slowly redshift and then blueshift by a tiny amount.How long must they observe to see a full cycle?
A) 25 days
B) 1 year
C) almost 12 years
D) It depends on how far away the observers are.

Question

Quizplus · Accepted Answer

The time it takes to observe a full cycle using the radial-velocity method is determined by the orbital period of the planet causing the observed Doppler shift. In the case of Jupiter, its orbital period is about 11.86 years. Therefore, the observers would need to observe the Sun continuously for almost 12 years to see a full cycle of Jupiter's gravitational pull causing the redshift and blueshift in the Sun's spectrum.

Observers in a Distant Solar System Are Watching Our Sun