The question suggests that a CME is caused by light. It’s not. The light of a CME takes minutes to reach earth—that is, we can “see it” because light travels at the speed of light (duh.)
The particles that actually cause the CME are traveling towards the earth at the rate they are ejected from the sun. Those things take 3-4 days to reach out into our orbit.
I didn’t think his question suggested light was the cause, but at least you two are having rational discussion about our solar system, and not about flying space turtles...
Right. So why would it take 3 or 4 days to travel 3000 miles? 31 mph?