Context: On the other hand, the crew on board the spaceship also perceives the observer as slowed down and flattened along the spaceship's direction of travel, because both are moving at very nearly the speed of light relative to each other. Because the outside universe appears flattened to the spaceship, the crew perceives themselves as quickly traveling between regions of space that (to the stationary observer) are many light years apart. This is reconciled by the fact that the crew's perception of time is different from the stationary observer's; what seems like seconds to the crew might be hundreds of years to the stationary observer. In either case, however, causality remains unchanged: the past is the set of events that can send light signals to an entity and the future is the set of events to which an entity can send light signals.

Question: How does the crew on board the spaceship perceive the stationary observer?
Answer: slowed down and flattened along the spaceship's direction of travel

Question: The crew's perception of what is different from a stationary observer?
Answer: time

Question: What the crew perceives as seconds might be seen as how long to a stationary observer?
Answer: hundreds of years

Question: What remains unchanged in both the cases of the spaceship crew and of the stationary observer?
Answer: causality

Question: How is the future perceived as by the crew?
Answer: Unanswerable

Question: Where does the future appear flattened and slowed according to the crew?
Answer: Unanswerable

Question: Why does the future appear this way to the crew?
Answer: Unanswerable

Question: Why does the crew believe that the universe is traveling slowly?
Answer: Unanswerable

Question: How long would it take for a spaceship to cross the universe?
Answer: Unanswerable

Question: How does the crew board the spaceship perceive the traveling observer?
Answer: Unanswerable

Question: The crew's perception of what is different from the ship?
Answer: Unanswerable

Question: What the crew perceives as seconds might be seen as how long to a moving observer?
Answer: Unanswerable

Question: What remains unchanged in both the cases of the spaceship crew and of the moving observer?
Answer: Unanswerable

Question: What is the set of events to which a moving observer can send light signals?
Answer: Unanswerable