DeltaV wrote:ladajo wrote:I would point out again that the clock is adjusted prior to launch for both GR and SR.
No one is arguing with that. Ground observers will see
both GR and SR effects. Only the GR effect is
intrinsic to the satellite. The SR effect is
extrinsic.
I think you are not decoupling the idea that as far as a rider aboard the bird is concerned, his clock is running at the same rate it was on the ground. Where as the ground based guy will see the rate of the launched clock speed up as it moves up to orbit (GR being the dominant in this argument).
ladajo wrote:And that it if it were not adjusted for both, the accumulated effect of both would grow over its lifetime.
Both
only if the satellite
keeps moving. There
is of course an adjustment for
both, to fix what is seen by
ground observers, but only the
actual GR effect accumulates
at the satellite.
The rates are different. The GR component will accumulate, as will the SR component,
during flight. Thus the need to include both to account for the rate difference. Once the flight is over, and the clock back on the ground, the rates will agree again, but the acumulated difference will remain. You can not unwind the counter. I think you are stuck on not seeing the difference between rate and counts, as well as the difference that the flying rider will see no change in his clock rate, whereas the ground guy, if watching, will see the flown clock speed up as it gains orbit (GR dominant in the argument).
ladajo wrote:Say you mounted a counter to the bird, to count the number of cycles, uncorrected. Once it returned to earth, it would show less cycles accomplished than a matching one on the ground.
...
This has been seen over and over again in flown orbital clocks at various largely different orbits.
So are you saying that satellites have "over and over again" been returned to
earth for this comparison? Citation needed. The results would be disputable anyway, given the nontrivial gravity variations, huge environmental excursions and interactions of numerous, nonlinear unknowns with the quirky atomic clocks.
I am saying that many clocks have been flown in different orbit profilies. LEO, MEO, HEO, etc. And they all function(ed) in accordance with the GR and SR corrections. This includes Geo based clocks with no SR correction to ECEF.
There has also been a couple of clocks rocket launched that did return and agreed as well on predictions. The space shuttle also has flown and landed many times, and it has onboard clocks. It has also recovered orbiting vehicles that had onboard clocks. The X-37 has also flown and returned with an onboard clock, as will OTV-2 here in a month or so. None of these clocks have undergone a "magical" reset upon returning to dirt. They count drifted on orbit in accordance with GR and SR prediction ofr rate change, and then rate matched upon return to dirt. The total counts did not magically change back upon return. The rate shift was a real event.
Your hand waving about other effects is chaff, and not pertinant to the discussion.
Of course you would see an apparent, SR-generated contribution to the observed total accumulation, from the ground, while the satellite is moving. The apparent SR "accumulation" requires a velocity difference for it to even exist. The SR "accumulation" exists only in the observers measurements, not in the satellite's clock, which has only a GR-caused, actual, total accumulation.
Now you are just wrong. I never said the flown clock would
notice the rate shift. The rate shift is transparent to the flyer for both GR and SR as long as he does not compare to the ground. As far as the flyer is concerned, the on board clock is running at the same rate is was on the ground. The only way the flyer would know something is different, would be to ask the dirt guy what his clock says, and how often it is changing (accumulation and rate). But if he did, he would see the rate between the clocks offset by GR and SR net. And, he would see, as a result of the rate offset, a difference accumulation in counts, based on the net GR/Sr offset of rate.
With real clocks, there is a real GR and SR correction to rate, that is neccesary. We know it works because without it we see the
micro sec clock drift. In real life, on the ground the to-be-flown clock is set to count less for oscillation events, so it is reporting running slow when compared to the gorund based clock. This is where the oscillations are the same, and the counts are the same, but the reporting mechanism (software) ignores some counts to "slow" the clock (38 micro sec). Once it is flown, and is in orbit, the drop in gravity effect (Altitude up=less GR=faster clock), combined with the increase in velocity (speed up=SR up=slower clock), gives a net adjust (38us), that allows our clock on the ground to be rate matched with the flying clock. The flying clock thinks it is running the same, but is now running fast compared to the ground clock, and the software count factor now reports it running at the same rate vice slow to the ground clock. How does it do this? It does it the same way it was doing it on the ground, it skips reported counts (38 micro seconds worth), but the actual oscillation rate has increased due to GR dominance. If you bring it back, it will rate shift down again, and run slow in comparison when sitting next to the ground clock. The only two things that changed are where it is in the gravitational context (GR), and how fast it was going compared to the ground clock (SR).
This is not imaginary. It is real, and the predictions work and agree for both GR and SR. If you do not think the SR part is real, then why correct for it? Why does clock rate change in accordance with GR
and SR predictions? Why does a Geo bird need no SR correction? And most importantly, with an un-adjusted flown clock why does it not rollback its indicated time (count) when it goes up as you claim it will roll forward on the way down? Your argument has a magical correction changing SR counts on the return, where is it on the way up?
In the real world, the two clocks are the same time and same rate on the ground next to each other. Then one is flown to orbit, on the way up to GPS orbit it undergoes a net increase in rate (faster for GR, slightly slower for SR), which uncorrected, shows more oscillations per unit time (ground). The ground counts these oscillations, and notes there are more per unit time(ground) than what is coming from the ground clock. In my argument, the returning flown clock would then do the reverse, it will slow its net(GR/SR) rate until once again on the ground, and it is rate matched again with the ground clock. None-the-less, while apart, its count got offset due to the change in rate, and it will indicate so when brought back together. This offset will be a function of the GR and SR components which gave the net(GR/SR) offset. The count offset will remain, reflecting the period of flight, while the rates will now be again matched.
It is the rate that shifts with relativity, not the count. The count is a consequence of the changed rate.