Thanks. I am not a physicist, an engineer. Trying to understand. But okay - try this: my friend in spaceship thinks my clock runs slow so, as he approaches Jupiter and sees the collision, he assumes my clock is running slow and therefore comet has hit before my class starts?
Posed question is that a comment plunges into Jupiter. Same time as my physics class starts on Earth. My friend is traveling towards Jupiter at a significant percentage of c. Would the person in spaceship say that the comment collision occurred before, after or as class started?
My answer: same...