Length Contraction of Relativity
Consider a spacecraft travels at velocity, v from one star to another.
What do We Need to Know?
Spacecraft: The astronaut, O’, with a clock (of O’) will always measure the proper time, Δt_p.
Ground Control: The officer, O, is fixed relative to the object (the distance between the two stars) and thus will always measure the proper length, L_p.
The Theoretical-minimum Derivation
Now, the derivation is as follows: