Context: Time has historically been closely related with space, the two together merging into spacetime in Einstein's special relativity and general relativity. According to these theories, the concept of time depends on the spatial reference frame of the observer, and the human perception as well as the measurement by instruments such as clocks are different for observers in relative motion. For example, if a spaceship carrying a clock flies through space at (very nearly) the speed of light, its crew does not notice a change in the speed of time on board their vessel because everything traveling at the same speed slows down at the same rate (including the clock, the crew's thought processes, and the functions of their bodies). However, to a stationary observer watching the spaceship fly by, the spaceship appears flattened in the direction it is traveling and the clock on board the spaceship appears to move very slowly.

Question: Historically, time has been closely related with what?
Answer: space

Question: In which of Einstein's two theories do time and space merge into spacetime?
Answer: special relativity and general relativity

Question: According to Einsteins two relativity theories, the concept of time depends on what?
Answer: the spatial reference frame of the observer, and the human perception

Question: A crew in a spaceship travelling nearly the speed of light will not notice the change in what?
Answer: in the speed of time on board their vessel

Question: How will the above mentioned spaceship appear to a stationary observer?
Answer: the spaceship appears flattened in the direction it is traveling

Question: What have a crew's thought processes usually been related to?
Answer: Unanswerable

Question: What is it called when a spaceship flies though space?
Answer: Unanswerable

Question: What does a space crew's thought processes depend on?
Answer: Unanswerable

Question: Flying through what makes the crew appear flattened out to each other?
Answer: Unanswerable

Question: What will an observer not notice the change of when watching a spaceship fly by?
Answer: Unanswerable

Question: Historically, what has been related to clocks?
Answer: Unanswerable

Question: In which of Einstein's two theories do time and clocks merge into spacetime?
Answer: Unanswerable

Question: According to Einstein's two relativity theories, what depends on the concept of clocks?
Answer: Unanswerable

Question: A crew in a spaceship traveling nearly the speed of sound will not notice the change in what?
Answer: Unanswerable

Question: How will the spaceship appear to an observer traveling at the same speed?
Answer: Unanswerable