Hi, I have attempted the following questions but I am unsure of my answers/method. Could you guys please help me through? A super fast spacecraft is moving at a speed of 0.80c with respect to the observers on Earth. The spacecraft leaves Earth in May 2004 on its way to a distant solar system. a) i) According to the observers in the spacecraft, 6.0 years have elapsed since leaving Earth. Calculate the time elapsed according to an observer on Earth From what I understand, the observers on the spacecraft measure proper time. Hence, I performed 6 times the Lorenz factor, using 0.80c as my v. I got 10 years as an answer. ii) Explain whether either measured time interval can be considered to be correct: I know that, according to the theory of relativity, both measurements should be correct. This requires two marks though and I do not know how to complement my answer. iii) Calculate the distance of the spacecraft from Earth according to an observer on Earth Here lies my central doubt. Should I simply perform velocity multiplied by time (the time measured by observers on Earth) or should I find the distance travelled according to the observers on the spacecraft and apply the length contraction formula? Thanks a lot in advance!