1. The problem statement, all variables and given/known data You are gliding over Earth's surface at a high speed, carrying your high-precision clock. At points X and Y on the ground are similar clocks, synchronized in the ground frame of reference. As you pass over clock X, it and your clock both read 0. (a) According to you, do clocks X and Y advance slower or faster than yours? (b) When you pass over clock Y, does it read the same time, an earlier time, or a later time than yours? (Make sure your answer agrees with what ground observers should see) (c) Reconcile any seeming contradictions between your answers to part (a) and (b). 2. Relevant equations Lo = L/γ t' = γ(t - vx/c2) or Δt' = Δt/γ γ = (1-u2/c2)-1/2 3. The attempt at a solution (a) Clocks moving in your (inertial) frame of reference appear to be ticking slower than clocks stationary in your frame. So the clocks X and Y appear to advance slower. (b) This is where I get confused. I see clocks X and Y running slowly, although an observer in that frame observes my clocks running more slowly. Say I'm traveling at (31/2/2)c so γ is 2, the observers on the ground measure my journey from above X to above Y to be t0. So when I pass over clock Y, they observe clock Y to be t0. (Since we should agree, I should also see t0, yet from the reasoning below I don't) They observe my clocks running half as fast, thus my clock only reads t0/2 when I am above clock Y. For me, the length of my journey is shorter due to length contraction. So in their frame I travel (t0) / (31/2/2c) or (2t0c) / (31/2), but in mine I travel half that. So my clock does register t0/2 due to the path being half as long. That part makes sense (I think?). Yet they appear slowed to me, by a factor of 2, from this I can conclude their clock should read t0/4! That makes no sense. My reasoning is twisted somewhere.