You are at rest (in the Earth frame) on your balcony, enjoying a rare San Diegothunderstorm. Suddenly, lightning strikes a tree which is only 85 m away from you, giving you quite a scare. This causes you to to jump in fright, when the sound reachesyou, 0.25 s (250 ms) later. A spaceship flying toward you and the tree happens to witness these two events, but they measure the distance between you and the tree to be only 40 m. a. Describe the possible cause-and-effect relation between the two events, or lack thereof.
b. Calculate the spacetime interval between these two events. What type of separa- tion (spacelike, timelike, or lightlike) do these events have? Does this agree with your answer to (a)?
c. Using the invariance of the spacetime interval between inertial reference frames, calculate the amount of time between the two events that the observer in the spaceship measures. What is the order of events that they observe?