• FTL travel vs FTL communication

    From amirjf@amirjfnin@aim.com to sci.physics.relativity on Sat Aug 8 16:20:38 2026
    From Newsgroup: sci.physics.relativity

    Why is it so much more common to speculate about FTL motion of matter
    than FTL waves/FTL communication?
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  • From ram@ram@zedat.fu-berlin.de (Stefan Ram) to sci.physics.relativity on Sun Aug 9 14:20:42 2026
    From Newsgroup: sci.physics.relativity

    amirjf <amirjfnin@aim.com> wrote or quoted:
    Why is it so much more common to speculate about FTL motion of matter
    than FTL waves/FTL communication?

    I do not know, but it all boils down to the

    /local speed of energy in a vacuum being limited to c/.

    Matter has mass which is a form of energy, so it is subsumed by that.

    Communication needs transfer of energy, so it also is subsumed.

    Waves have several different concepts of speeds (like phase
    velocity or group velocity), but the relevant speed of the
    transfer of energy by the wave is subsumed.

    The chatbot commented:

    |FTL communication (often called the "Ansible" or subspace
    |radio in sci-fi) and FTL waves (like tachyonic fields or
    |Alcubierre warp bubbles) are speculated about just as much,
    |if not more, than physically moving chunks of matter through
    |space.

    . In an entangled quantum system, internal information indeed
    /is/ transferred FTL, but this does not involve transfer of
    /energy/ nor can it be used by someone outside of the system
    to transfer his /external information/. It can only be used for
    the purpose of making the entangled behavior possible. So what
    you get from it is entangled behavior, which cannot be used
    to transfer energy nor your own information.


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