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comment by rob05c
rob05c  ·  3115 days ago  ·  link  ·    ·  parent  ·  post: Hunt for gravitational waves to resume after massive upgrade.

If gravity is instantaneous, it could theoretically be used for faster-than-light communication, travel, and I think causality violations. General relativity depends heavily on the speed of gravity not exceeding C, so it would have to be essentially rewritten.

Relevant: https://physics.stackexchange.com/questions/26742/does-gravity-travel-at-the-speed-of-light

    The rate of orbital decay of binary pulsars is, among other factors, dependent on the speed of gravity. The in-spiral rate of one binary pulsar system has been measured and found to agree with the rate predicted by general relativity to within a 0.2% margin of error.

As an engineer, I kind of hope gravity is instantaneous. But I doubt it.

Reminds me of Time for the Stars, in which telepathy is found to exist, and be instantaneous, and is used for communication at near-light speeds, eventually being the foundation of FTL. Good story.





mk  ·  3115 days ago  ·  link  ·  

Yes, I am a stubborn contrarian here. It's probably hope motivtated as well. I do wonder what the orbital decay of these stars would look like with instantaneous gravity.

There is such a thing as instananeous information transmission, of course. It just must reside within a quantum system, and theoretically can't be made useful without.

thundara  ·  3115 days ago  ·  link  ·  

Your hypothesis would make the plot of Interstellar make more sense!