Is there any point at which the distance becomes too large to the extreme where you basically get “deleted” from existence?

  • ProfessorScience@lemmy.world
    link
    fedilink
    English
    arrow-up
    21
    ·
    14 hours ago

    Is there any point at which the distance becomes too large to the extreme where you basically get “deleted” from existence?

    This is basically what the definition of “observable universe” is. It is the part of the universe that is close enough in space and time for light to reach us. So if you say they get transported to the observable part of the universe, then yes, their signals will eventually reach earth. But the closer they are to the edge of the observable universe, the longer the signals will take to reach, and the more red shifted they will be due to the expansion of the intermediate space as the signals travel to Earth.

    Note that there are some semantics at play; “observable universe” might refer to the parts of the universe that have emitted light in the past that is reaching earth now. But the the light emitted by those places now might never reach Earth because they are now too far away. So if these astronauts got sent to one of those places then no, their signals would not reach earth.

    • Scubus@sh.itjust.works
      link
      fedilink
      arrow-up
      3
      ·
      3 hours ago

      Afaik theres the observable universe (their signals will reach us) and the smaller interactactable universe (our signals will reach them).

    • whoami@reddthat.comOP
      link
      fedilink
      arrow-up
      4
      ·
      14 hours ago

      To offer a value, let’s say they get ejected about 46.5 billion light years away (the radius of the observable universe today).

      • ProfessorScience@lemmy.world
        link
        fedilink
        English
        arrow-up
        12
        ·
        13 hours ago

        I think this would fall in to the latter scenario. 46 billion light years is the edge of the observable universe in the sense that light emitted by those regions has reached us by now. But these regions are beyond the cosmic event horizon, which is the distance at which light emitted now will ever reach us. That distance is about 17 billion light years.

        • Nougat@fedia.io
          link
          fedilink
          arrow-up
          7
          ·
          12 hours ago

          I believe that it would also be true that at a much much closer distance, the signal strength would fall below the CMB and become practically invisible, due to the inverse square law.