I'm lost. Time dilation would continue to effect the synchonized clock, right?
On Fri, Nov 15, 2013 at 10:17 PM, <[email protected]> wrote: > On 16/11/2013 12:25 PM, leaking pen wrote: > > > > *However if we consider ourselves using our initial clock synchronisation, > then we know our true accumulated speed because we can see that the light > pulse is only just travelling a bit faster than us (it takes the pulse a > very long time to travel from the back of the ship to the front) and so we > are travelling just a shade slower than c. Also since any clock tick rate > is given by an oscillation time, if we use the round trip time of a light > pulse travelling from the back of the ship, to the front and back again, as > our oscillation tick time, then we know that our time is ticking a lot > slower than it was before we accelerated. If we divide the known distance > (10 light years) by our speed measured this way (~0.99c or thereabouts) > then we know how many ticks of our (slowed down) clock will happen in that > distance - and it will be 1 years worth. Since our clock seems to us to be > ticking at its normal rate, we will get there in what feels to us like a > year." * > Wouldnt the light take the same amount of time per our observation to > travel the ship? Isn't that fact basically defined by relativity? > > The question is how do you measure the time? If you measure the round > trip time, then Yes it never changes - because that is our definition of > time. But if we want to measure the *one-way* velocity so that we can > compare it with the other *one-way* velocity, then we need two clocks - one > at each end. If we synchronise these clocks by any means just before we > make the measurement, then Yes - again it takes exactly the same amount of > time to travel in each direction along the length of the ship. That is > guaranteed by our synchronisation technique. > > But .... if we keep the initial synchronisation that was established > before we started accelerating, then using this time at each end of the > ship and pulses of light traversing this distance, we can discover our > speed relative to when the clocks were initially synchronised - and this > can indicate a speed in excess of c! > > Consider the Eiffel tower experiment. The clock at the top runs faster > and the time difference accumulates until a light pulse sent from the top > when the clock reads say 10am, could arrive at the bottom clock when it > reads 9:59:59 - which is before it left! This same effect occurs without > any gravitational field to mess with time, and only with the help of > acceleration. If you got a reading like this from your space ship > measurement, you would know that you had accelerated such that your > accumulated speed relative to when you synchronised your clocks was greater > than c. > >
