Maciej Wozniak wrote:
> On Tuesday, 28 September 2021 at 16:51:08 UTC+2, tjrob137 wrote:
>> On 9/28/21 12:45 AM, Julio Di Egidio wrote:
>> > That's all and simply *completely wrong*, the whole standard little
>> > tale of clocks slowing down...
>> You REALLY should learn something about the subject before attempting to
>> write about it.
> First, you should learn that you're FORCED!!! To THE BEST WAY!!!
The best way to describe Nature is obviously one that allows us to explain
her past behavior and predict correctly her future behavior, to be able to
use that knowledge in various ways.
[For example, a rocket that does not correctly sufficiently gravity will
fall down instead of reaching outer space. And a rocket that is
designed based on the wrong model that the gravitational acceleration
would be constant with altitude will waste fuel and can carry less
payload that it otherwise would have been able to.]
Therefore, it is necessary to describe Nature how she presents herself to
us, putting aside all (your) fantasies of something simpler (just because
you are/one is lacking the skill or willpower to understand her
>> Nonsense! -- that simply does not happen, because the reunion of the
>> twins happens at a single event (point in spacetime). So they
>> necessarily arrive at the same time, using any coordinate system
>> whatsoever. Of course they arrive with different values of elapsed
>> proper time (and therefore different values displayed on their personal
> In the meantime in the real world, however, GPS clocks keep
> indicating t'=t,
There is no such single thing as a “GPS clock” to begin with.
The Global Positioning System (GPS), like all satellite-based systems,
consists of a ground segment, a space segment, and a control segment. The
control segment includes atomic clocks (they are on the ground, e.g. at the
USNO¹), and so does the space segment (the clocks are aboard the GPS
satellites). [The ground segment are users of GPS: Organizations and
private individuals, and their GPS receivers.]
Put simply, the clocks aboard the satellites have been TUNED ACCORDING TO
GENERAL RELATIVITY so that they KEEP being in sync with the ground clocks.
(In actuality, not the satellite clocks, but the signal frequency has been
tuned to compensate for the MEASURED relativistic effects.)
> just like all serious clocks always did.
You are continuing to babble “t'=t” like an old fart, without ever
explaining what that is even supposed to mean.
[It is only from your other statements that one is forced to conclude that
you think that GPS would work (especially its time service) even if the
satellite clocks had not be tuned in some way, and that that would be so
because you believe that the theories of relativity as a whole would be
> Whatever FORCES poor idiot Tom - GPS engineers were resistant to it.
Oh for crying out loud. For the umpteenth time:
The inventors of, and the engineers involved in, the development and
construction of GPS *specifically* included the possibility for the sending
frequency to be adjustable in the likely case that the aforementioned
correction would be necessary.
Then they TESTED whether there would be a measurable difference in elapsed
proper time on the satellites as compared to measurement by ground clocks
(which they could do because the satellites are SENDING the satellite time
IN THE SIGNAL). And lo and behold, the difference was ALMOST PRECISELY as
general relativity predicted.
As a result, the SENDING FREQUENCY was adjusted to COMPENSATE for the THUS
MEASURED general-relativistic effect.
It is all described very clearly IN THEIR OWN TECHNICAL REPORT (of 1977).
A digitized version has been PUBLICLY available for YEARS:
Quote (AGAIN) from page 11 of the report:
| […] Inclusion of the Panama frequency offset of +0.6 pp 10¹² produces an
| NTS measured value of +443.1 pp 10¹². Comparison of this value
| to the predicted value of the relativistic offset of +445.0 pp 10¹² gives
| a difference of −1.9 pp 10¹². On day 215, 1977, the NTS-2 PRO-S output
| signal was offset (Fig. 16) through the use of a frequency synthesizer
[“pp 10¹²” means “parts per trillion (short scale)”.
+445/10¹² · 86'400 s ≈ +38.448 μs/d. Compare
And it is the same problem and solution for all other navigation satellite
systems (NSS); in particular the fully operational GNSSs (global …): GLONASS
(USSR/Russian Federation), BeiDou (People’s Republic of China), and Galileo
You simply have no clue what you are talking about, but you are too self-
absorbed, attention-seeking, or simply SENILE to (be able to) even consider
that possibility (let alone have yourself be educated by rebuttals or even
to educate yourself by doing some ACTUAL research on the matter). How sad.
[This is just yet another correction of your false claims. I will
not react to your foreseeable irrational response as those are facts
which are not debatable. (You are entitled to your own opinion, but
not to your own facts.) So you should save the bandwidth for future
generations as they will certainly need it.]
Two neutrinos go through a bar ...