A quick note from: (i'm too lazy to do the calculations right now) http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps....
If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! The whole system would be utterly worthless for navigation in a very short time.It could reasonably be the case that we just adjusted the clocks on the satellites by .05% or whatever the drift rate is by measuring them against known points until we get it right. Good enough engineering.
Eventually someone would have asked some scientists to explain why it's happening.
The issue you have is that the dilation effects aren't static, they're all relative to each satellite and ground observer and are constantly shifting based on the orbits. Basically the premise you have to accept to allow for "just adjust the clocks" is too basic. This is why both general and special relativity come into play in GPS. You might get away with adjusting for a single observer, but not all observers.
Note that we already have the clocks purposefully skewed to account timewise for their orbital speed and still require constant updates. I just don't see that happening through "good enough engineering". If you're a nanosecond off you're off by over 1 kilometer and things get worse from there.
Plausible as a hypothetical gedanken experiment? I suppose, plausible in reality? I'm skeptical that you'd be able to do it. Would be akin to launching a rocket to the moon without understanding how to fly.
And hence have discovered GR in the process. Alternatively (and more likely) we would have decided the idea simply doesn't work.
No, we would just keep beating on it until it works. It's a myth that science always precedes engineering. It's a very regular drift, and worst case scenario, if they just couldn't work it out, they'd build several ground stations in known locations, derive corrections as those drift, and upload corrections into the system periodically. (Similar things are done today: https://en.wikipedia.org/wiki/Differential_GPS )
Even with the science that we have, there's still fudge factors and empirically-determined values we have to use anyhow, because the Earth is not homogeneous and we have to take its slightly-lumpy gravity field as a given, not something we can "scientifically" determine. (Of course we "use science" to determine the lumps, but the lumps themselves are simply a given.)
That's not the question; the question is, are we forced to give up engineering if we don't have "the science" yet?
And the answer is an objective "no", from abundant past human history. There's this myth sold that science always precedes engineering that is very, very popular. I'm not even sure where it's coming from. Oral history in primary education, maybe. But it's a myth that engineers themselves can ill afford.
The vast majority of practical programming is programming running way, way ahead of the "science", which occasionally takes point samples of how 10 college sophomores behave under a certain limited experiment.
I don't understand why would you come up with such "objective" statements unless you really think it's not necessary to know anything about the history of science and engineering to have a strong opinion about them.
Well, humans have been crafting optical lens way before Maxwell ;). And even way before [1] Descartes and Newton decided to study light.
For everything out of reach of our senses, like the examples you gave, we need formal science. But for everything humans can see, smell or touch, we're pretty good with empirical observations : chemistry, fluide dynamics, genetics and mechanics where comonly used way before formal science was even a thing.
Possibly amended to include "to a degree that justifies the spending"
Fascinating to wonder how modern physics community worldview would be different, if GR had gone [empirical anomaly -> new theory], and ended up in the same place rather than [thought experiment -> empirical proof]. (IAN a historian of physics - forgive me if I have that wrong.)
> Alternatively (and more likely) we would have decided the idea simply doesn't work.
I don't think that's true. Consider the Bell Labs guys who won the Nobel Price for Microwave Background Radiation, who were just trying to remove the noise their antenna was receiving.
Without that, you don't have much opportunity to discover the basis of the correction (which, as others have pointed out, is just discovering GR, anyway.)
The reason is that for econmics reasons, GPS developers work hard on noise reduction. Once you eliminate all the "technical" forms of noise, you're left with the "scientific noise".
In every kind of clock.
I would hope in this scenario that that would have been noticed and it would have aroused sufficient curiosity to investigate and eventually discover that the effect was due to time itself flowing at a different rate.
Finally, after an enormous effort being able to tell your manager that the error is in the space-time of the universe.
It reminds me of something I read about the search for what we would now call "violations of conservation of energy". Scientists kept coming up with more experiments to try to show this phenomenon, but none of them worked. Eventually they were forced to conclude that that's just the way it is:
"A perfect conspiracy is a law of nature."
However, by studying and understanding such events, we can test and improve our theories of physics, which may lead to breakthroughs in technology we can only dream of.
For example, general relativity would have been considered completely useless knowledge for any practical purpose when it was first formulated in the early 20th century. It only has any measurable impact at extreme velocities and gravities. In the late 20th century, it proved instrumental to creating accurate enough models for measuring the time delay of signals from satellites, creating what we now know as the GPS system.