Large groups of sunspots can be relatively long-lived (a few months) and they remain essentially fixed at the same physical location on the photosphere throughout their lives. suppose a sunspot appears to move from the center to the edge (limb) of the sun's disk in 7 days. what is the approximate rotation period of the sun? (a rough estimate will suffice; don't worry about not being able to see the sunspot if it is exactly at the edge of the sun.) [p.275 q.14]