We know that light and even gravitational waves propagate at the speed of light.

So if something catastrophic happened to the black hole at the center of our galaxy (about 26,000 lightyears away), would there be any way for us to have advance knowledge of it before we could observe it with telescopes or before we could measure the gravitational changes?

Ludicrous example: say the black hole at the center of the galaxy disappeared 25,999 years ago. Is there a way we would have known about it by now, or do we just have to wait out another year to see if we’re all screwed?

  • Num10ck@lemmy.worldEnglish
    63·
    1 year ago

    i guess if you had some super crazy distant probe observing the black home and it’s memory bits were quantum entangled with a receiver device near us, we might know instantly-ish? but would need to wait millions of years for that probe to be placed to begin with and hope the systems don’t corrode or corrupt or fail in those millions of years. and what would you do with the info? tell everyone?

    • Kyle@lemmy.caEnglish
      5·
      1 year ago

      I thought FTL communication is just a fun typical science fiction understanding of quantum entanglement.

      I thought we would still have to know what is going on at the probe via another means to know or decode the message sent by the entangled particles to their counterparts on Earth.

      Kind of like putting two letters in two envelopes but we don’t know what colour they are, just that they will always be opposite colours. Even the person arranging them doesn’t know which colour they are. We don’t know if a red letter is sent to London or a green one is sent to LA or what colour they’ll be at all. But when we open the letter in London and see that it’s the red one we know the other one in LA is green.

      So no matter where or when the person with the red letter is, they’ll always know the other person has the green one once they open the letter. But no information has been mysteriously transported across space and time, just the correlation between the two has been discovered.