(a) Earth's mass is 6 * 10^24 kg, and its distance from the Sun is 1 AU.
What would the resolution of a spectrograph have to be, in terms of its 
minimum delta(lambda)/(lambda), in order to detect the effect of Earth on the Sun, 
from the vantage point of a distant astronomer?

(b) How many times larger or smaller is the effect of Earth on the solar system's 
center-of-mass velocity compared to the effect of Jupiter?  Does this ratio pose
a problem with detecting an Earth-like planet in a solar system that also
contains Jupiter-like planets?