The Wright Brothers didn’t need Theory of Relavity to build a plane that flew. Can we extend that further and say that Newtonian mechanics and all other collective science knowledge before TOR was enough to build rocket propulsion and get to the moon?
I’m including any technology that was needed to get to the moon (the computers in Apollo, radio communications, etc).
I’m ruling out bizarre “butterfly effect” type stuff …e.g. well, if there was no Theory-of-Relativy, then John wouldn’t have been at that physics class, and then he would’t have met Larry, which led to development of rocket engine, etc.
I guess another more general way of asking this question is: how does Theory of Relativity get applied in our everyday lives today. (For example, I remember hearing that the precise timing alignment of GPS satellites and surface beacons are related to time anomalies predicted by TOR.)
I can only speculate, but a three-day voyage to the moon does not seem to require the kind of split-second timing that would come into play in TOR, such as time dilation from achieving escape velocity, or changes in gravity. I believe that the course was being constantly adjusted anyway, and such differences are at the noise level.
GPS does depend on split-second timing, however, since the whole thing depends on differences in the timing of signals from the satellites, with pretty good precision. The same is probably true of many methods used for cosmological observations, knowing how light is affected by passing by a massive star, for example.
The only place where I think it might have been an issue is the ground station timing systems, which use cesium beam frequency standards (atomic clocks). Variations in local gravity affect the resonant frequency of the cesium beam. When clocks are compared, a correction needs to be made for the altitude of the clocks. This might also affect the ranging system, which uses propagation delay and doppler to determine the range and range rate of the spacecraft from the ground station.
Using TOR instead of Newtonian Physics, is like upgrading your Porsche to a Bugatti Veyron: Yeah, you got an even better car (and perhaps the best!), but is it really a practical decision?
[Slight hijack]While I doubt ToR itself was required for the moon landings, how about Quantum Mechanics? Wasn’t the Transistor (the basic building block of the modern computer) a result of exploring the possibilities inherent in Quantum Theory?
The Theory of Relativity does have to be accounted for in GPS location. The speed of the satellite is fast enough to create errors if it isn’t accounted for, and the mass of the Earth creates further General Relativity effects. If not accounted for, GPS would be hundreds of miles off after only a few days.
Another factor to consider, Relativity was derived, in part, to explain some of the failures of Newtonian physics. Specifically, Newton’s Laws alone, cannot be used to accurately describe the orbit of Mercury. For planetary orbits, outside of Mercury, Newton alone is something like 95% accurate. Maybe even higher when dealing with such a small and simple system as the Earth-Moon system. But I’m not sure that anyone would have been willing to put anyone into orbit if there were no way to accurately predict and describe what Mercury does - without that theoretical underpining, the chance of something misunderstood biting the project on the ass would seem to be too high to risk.
For Earth bound systems, the difference between Relativity physics, and Newtonian physics is easily ignorable. When we start talking about moon shots where accuracies had to be within fractions of a percent, I suspect we did need it.
Television picture tubes don’t work unless designed and operated with Einsteinian relativity in mind, because the electron beam moves at high enough velocity that you have to design the deflection with the electron’s relativistic mass in mind. Could we have done the moon landing without picture tubes? We certainly did use many of them, the way we did it.
>Do you have some kind of cite for that claim?
I learned of this myself studying relativity as part of getting my physics degree, but there are plenty of examples out there.
“The speed of the electrons can be calculated from an energy balance: 0.5mv2 = eV, or v = √2eV/m. This equation is approximately correct up to accelerating voltages of about 2500 V, when the electrons are accelerated to a tenth the speed of light. For higher voltages (as in most TV picture tubes) relativistic dynamics must be used.”
Not a hijack since someone said Newtonian Physics was all that was needed. We might have been able to go to the moon without QM, but we didn’t. And it would not have been easy. Any integrated circuits used in the space program would not have been available w/o QM (unless we somehow discovered semiconductor devices w/o really understanding how they worked).
As for ToR affecting everyday life… nuclear power and nuclear weapons are the first thing that come to mind. You need to know e = mc^2 for that.
I just want to compliment our guest OP on an interesting, well thought out, and well written OP. Not too common among “guest” posters in this forum.
Doppler shift skews the radio frequencies that were used for communication. While it is pretty easy to adjust the tuning, this is a relativistic effect that needed to be accounted for.
I don’t know about that. We sent up a fair number of unmanned vehicles to the moon before Apollo. The first ones crash landed on the surface. The Surveyor program (my father designed the steering control systems for Surveyor) was a vehicle that soft landed on the moon and sent back data including pictures. By the time we started on Apollo, we knew that there wouldn’t be a misunderstanding of that nature.
I didn’t learn about TOR when they taught me how transistors worked, nor did they mention transistors in a quantum mechanics course.
What does relativity have to do with the behavior of electrons in a semiconductor? Does TOR explain tunneling?
For sound, no. For light (including radio waves), yes. carnivorousplant, the Theory of Relativity will tell you precisely zip about transistors. I believe Noone Special’s argument is that we also needed Quantum Mechanics to go to the moon.
