What the Global Positioning System tells us about the twin’s paradox

von Tom Van Flandern 

What the Global Positioning System tells us about the twin’s paradox
Tom Van Flandern

In: Episteme. An international journal of science, history and philosophy. Nr. 6,
Parte 2. 2002, 21. Dez., ca. 10 S.

Die Forschungsgruppe G.O. Mueller referiert in der Ergänzung des Kapitels 4 ihrer Dokumentation diese Arbeit von Tom Van Flandern:


„Abstract. – In the GPS, all atomic clocks in all reference frames (in orbit and on the ground) are set once and stay synchronized. We can use this same trick to place a GPS-type clock aboard the spacecraft of a traveling twin. That clock will stay synchronized with Earth clocks, allowing a clear resolution of the twin’s paradox in special relativity – why the traveler expects to come back younger, and why the stayat-home twin is not entitled to the same expectation.“ 

Stellt die Lorentz-Äther-Theorie als Lorentz-Relativitätstheorie von 1904 der SRT Albert Einsteins von 1905 gegenüber. Die SRT führt zwei Neuerungen ein: 

(1) für das 1. Postulat (RP) die „Äquivalenz“ = Gleichberechtigung aller Inertialsysteme (und damit Ausschaltung des Äthers): „This first postulate of SR [„Einstein’s special relativity (SR)“] makes the Lorentz transformations reciprocal; i.e., they work equally well from any inertial frame to any other, then back again; so it has no meaning to ask which of two identical clocks in different frames is ticking slower in any absolute sense.“ 

(2) für das 2. Postulat (C-K) nicht nur die Unabhängigkeit der Lichtgeschwindigkeit von der Quelle, sondern auch von dem Bewegungszustand des Beobachters: „The second postulate of SR makes the speed of light independent of not only the speed of the source (which is also true generally for waves in any medium, including luminiferous ether), but also independent of the speed of the observer (which is a feature unique to SR).“ 

Verweist darauf, daß diese Postulate nie experimentell bewiesen worden sind: „Today, many physicists and students of physics have acquired the impression that these two postulates have been confirmed by observations. 

However, that is not the case. In fact, none of the eleven independent experiments verifying some aspect of SR [1] is able to verify either postulate.“ 

„Conclusions. – In LR [„Lorentzian relativity (LR) theory“], one reference frame (the local gravity field) is preferred; and speed cannot affect time, but only the rate of ticking of mechanical, electromagnetic, or biological clocks. However, just as we do not assume that time has been affected when the temperature rises and causes a pendulum clock to slow down, LR says that changes in clock rates are changes in the rates of physical processes, and do not affect space or time. 

So by carrying an on-board GPS clock on the spacecraft, we are offered a clear choice between models: Earth time can be what SR infers it is, or it can be what the GPS clock says it is. In the former case, SR works, but leads to heavy-duty complexities and fantastic inferences about the nature of time at remote locations. 

Moreover, the proof that nothing can travel faster than light in forward time stands intact. In the latter case, LR works with great simplicity and in full accord with our intuitions about the universality of the instant „now“. 

And the speed of light is no longer a universal speed limit because time itself is never affected either by motion or by gravity. 

Aside from these practical difficulties with the use of SR in the GPS, Einstein’s special relativity is also under challenge in a more serious way from the „speed of gravity“ issue, because the proven existence of anything propagating faster than light in forward time (as all experiments indicate is the case for gravity) would falsify SR outright [6, 7]. So it is entirely possible that reality is Lorentzian, not Einsteinian, with respect to the relativity of motion. In that case, physics may have no speed limit when the driving forces are gravitational or electrodynamic rather than electromagnetic in nature. And that may be the most important thing that the GPS has helped us to appreciate.“ 

The speed of gravity: what the experiments say
Tom Van Flandern

WWW 2006. 15 S. URL http://www.metaresearch.org/cosmology/speed_of_gravity.asp – Erstmals in: Physics letters. A. 250.1998, S. 1-11. 

S. 1: „Abstract. – Standard experimental techniques exist to determine the propagation speed of forces. When we apply these techniques to gravity, they all yield propagation speeds too great to measure, substantially faster than light-speed. This is because gravity, in contrast to light, has no detectable aberration or propagation delay for its action, even for cases (such as binary pulsars) where sources of gravity accelerate significantly during the light time from source to target. 

By contrast, the finite propagation speed of light causes radiation pressure forces to have a non-radial component causing orbits to decay (the „Poynting-Robertson effect“); but gravity has no counterpart force proportional to v/c to first order. General relativity (GR) explains these features by suggesting that gravitation, unlike electromagnetic forces, is a pure geometric effect of curved Space-Time, not a force of nature that propagates. 

Gravitational radiation, which surely does propagate at light-speed but is a fifth order effect in v/c, is too small to play a role in explaining this difference in behavior between gravity and ordinary forces of nature. Problems with the causality principle also exist for GR in this connection, such as explaining how the external fields between binary black holes manage to continually update without benefit of communication with the masses hidden behind event horizons. These causality problems would be solved without any change to the mathematical formalism of GR, but only to its interpretation, if gravity is once again taken to be a propagating force of nature in flat Space-Time with the propagation speed indicated by observational evidence and experiments: not less than 2×10^10c. Such a change of perspective requires no change in the assumed character of gravitational radiation or its light-speed propagation. 

Although faster-than-light force propagation speeds do violate Einstein special relativity (SR), they are in accord with Lorentzian Relativity, which has never been experimentally distinguished from SR-at least, not if favor of SR. Indeed, far from upsetting much of current physics, the main changes induced by this new perspective are beneficial to areas where physics has been struggling, such as explaining experimental evidence for non-locality in quantum physics, the dark matter issue in cosmology, and the possible unification of forces. 

Recognition of a faster-than-light-speed propa-gation of gravity, as indicated by all existing experimental evidence, may be the key to taking conven-tional physics to the next plateau.“

Eine Antwort zu “What the Global Positioning System tells us about the twin’s paradox”

  1. J, Bajnok

    Speed of gravity:

    Laplace: speed of gravity > 3 x 10^7 x c

    Lehmann-Filhes (1881) and Hepperger (1884) 10^5-10^7 x c

    (c – speed of light)

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