A space 100m long space ship travels to planet X which is a distanace of 6E11m from Earth. It travels at 90% of the speed of light. Who measures proper time for the journey?
A. Observer on the earth
B. Pilot of space ship
C. Another independent observer
D. The cosmic time keeper
This question is part of H3 Time dilation, length contraction
Asked by Gboulton
, Last updated: Apr 19, 2018