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Physics

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  • $\begingroup$ You seem to be implying that gravity travels faster than the speed of light. For example, if I possessed the technology to reverse Jupiter's obit, by your reasoning you could detect that instantly on Earth from the change in gravitational pull, before the light has time to reach me so that I can see it directly. In other words, you're describing an ansible. Obviously, that can't be correct. $\endgroup$
    – JBentley
    Commented Jul 6 at 15:42
  • $\begingroup$ @JBentley it's correct though. There is no faster-than-light communication, but nature manages to "forecast" the position of the source to remarkable precision. See arxiv.org/abs/gr-qc/9909087 for a detailed discussion. $\endgroup$
    – Sten
    Commented Jul 6 at 18:26
  • $\begingroup$ @JBentley you're correct that in that case it will not point to where Jupiter actually is, because you are changing the acceleration of Jupiter during the time you're reversing its orbit. It will point to where Jupiter would have been without your intervention, for the next 40 minutes (give or take 8 minutes depending on where the Earth is). No FTL signaling. $\endgroup$
    – BaddDadd
    Commented Jul 7 at 15:47