5 ms·

Isn't it even more technically accurate to say that it hasn't happened yet, and actually won't ever happen, in our frame of reference?

xwdv 4y ago
The event has already happened, even though we cannot see it yet. There is no way to reach some state where you could still exist in a universe where the event hasn’t happened. If you traveled at the speed of light to the event location, you would see it has already happened. Since the speed of light is the fastest possible movement, there is no way to arrive at the event location faster than that, any faster movement means you would be time traveling back into the past in attempt to reach the event before it happens. Any possible event that happens in our daily lives starts off with two possible states: happened or didn’t happen. When one of those states is eliminated, the event status is resolved and reality is updated. Usually we see these updates occur damn near instantly. In this case, in this universe, the “didn’t happen” state has been thoroughly eradicated. But at these distances, we don’t see updates yet, but it has happened. Therefore, you can consider the event as having happened. It was… inevitable.
- jrootabega 4y ago
  The object has been fully dragged across the event horizon into the black hole?
- anonymouskimmer 4y ago
  > Since the speed of light is the fastest possible movement, there is no way to arrive at the event location faster than that, any faster movement means you would be time traveling back into the past in attempt to reach the event before it happens. I don't quite get the time travel bit. I've seen too many sci fi and fantasy shows where time is effectively frozen while supernatural entities move about. Other than the supernatural entities moving about, the instant is the same everywhere, it doesn't go back. And if I see an event at Alpha Centauri, and immediately teleport there, the light wave is still at Earth. I haven't traveled back in time to the origination of the light wave at Alpha Centauri. And my light wave will not reach Earth until another ~4.3 years has passed after the first light wave that prompted my journey to Alpha Centauri. So the observer will not see anything unusual. I will not have rewritten the light pattern they saw. Also I think astronomers do see events which appear to be violations of causality, but are actually just gravitational distortions of the light traveling from an event. So interference with the travel of light from an event can't really be seen as traveling back in time.
  - haneul 4y ago
    If you were to teleport to the appropriate space coordinates upon seeing the event, the event being in the past (since you are seeing the event with light delay), you would not arrive in time to see it up close. If you wanted to see it up close, you would have to travel into the past, since your teleportation would have to include a translation of time coordinates, not just of space coordinates. Also, although order of events is variable, causality is (I believe) currently assumed to be absolute, so while two observers can differ on which came first between events A and B, this is only possible if A and B’s light (really, information) cones do not intersect such that one precedes the other causally. Suppose A does not intersect B by light cone, and you can instantly teleport. Then you can interact at A, teleport and interact at B, then immediate teleport everywhere in the universe, causally intertwining all frames before causality can physically propagate to those coordinates. Then you have time traveled to such an extent that I have no idea how the universe reconciles such a thing.
    - anonymouskimmer 4y ago
      It seems to me a bit like scattering a bunch of sand onto a still body of water. The sand hits simultaneously at all points, creating waves that interfere and reinforce each other. Why does the universe have to reconcile? Just let the waves do what they do and move on from that.
      - haneul 4y ago
        The simultaneity and single reference frame of the sand hitting example means there are no contradictions present. Assuming a finite speed limit to information transfer exists, exceeding that limit means you can create a potentially unlimited number of contradictions in state. It would be like watching the waves do what they do, but none of it happened, because no matter what you think you saw, there is at least one contradiction (due to the teleporting meddler). Like if you imagine any one state, and you meddle it to be impossible, as if doing Cantor’s diagonalization on the potential state space (if you can do literally instant teleportation and action with no cooldown).
- anamexis 4y ago
  Or you can consider the event as "inevitably will happen." Just as valid.
amluto 4y ago
No, it already happened in our frame of reference. Our frame of reference, in special relativity, is a spacelike slice through the universe, “now” is what we would conventionally think of as “now”, and light moves at the speed of light. In general relativity, things get weird and frames are more of a local phenomenon, but as long as you stay away from the event horizon, it’s not that weird.

xwdv 4y ago

The event has already happened, even though we cannot see it yet. There is no way to reach some state where you could still exist in a universe where the event hasn’t happened. If you traveled at the speed of light to the event location, you would see it has already happened. Since the speed of light is the fastest possible movement, there is no way to arrive at the event location faster than that, any faster movement means you would be time traveling back into the past in attempt to reach the event before it happens. Any possible event that happens in our daily lives starts off with two possible states: happened or didn’t happen. When one of those states is eliminated, the event status is resolved and reality is updated. Usually we see these updates occur damn near instantly. In this case, in this universe, the “didn’t happen” state has been thoroughly eradicated. But at these distances, we don’t see updates yet, but it has happened. Therefore, you can consider the event as having happened. It was… inevitable.

jrootabega 4y ago
The object has been fully dragged across the event horizon into the black hole?
anonymouskimmer 4y ago
> Since the speed of light is the fastest possible movement, there is no way to arrive at the event location faster than that, any faster movement means you would be time traveling back into the past in attempt to reach the event before it happens. I don't quite get the time travel bit. I've seen too many sci fi and fantasy shows where time is effectively frozen while supernatural entities move about. Other than the supernatural entities moving about, the instant is the same everywhere, it doesn't go back. And if I see an event at Alpha Centauri, and immediately teleport there, the light wave is still at Earth. I haven't traveled back in time to the origination of the light wave at Alpha Centauri. And my light wave will not reach Earth until another ~4.3 years has passed after the first light wave that prompted my journey to Alpha Centauri. So the observer will not see anything unusual. I will not have rewritten the light pattern they saw. Also I think astronomers do see events which appear to be violations of causality, but are actually just gravitational distortions of the light traveling from an event. So interference with the travel of light from an event can't really be seen as traveling back in time.
- haneul 4y ago
  If you were to teleport to the appropriate space coordinates upon seeing the event, the event being in the past (since you are seeing the event with light delay), you would not arrive in time to see it up close. If you wanted to see it up close, you would have to travel into the past, since your teleportation would have to include a translation of time coordinates, not just of space coordinates. Also, although order of events is variable, causality is (I believe) currently assumed to be absolute, so while two observers can differ on which came first between events A and B, this is only possible if A and B’s light (really, information) cones do not intersect such that one precedes the other causally. Suppose A does not intersect B by light cone, and you can instantly teleport. Then you can interact at A, teleport and interact at B, then immediate teleport everywhere in the universe, causally intertwining all frames before causality can physically propagate to those coordinates. Then you have time traveled to such an extent that I have no idea how the universe reconciles such a thing.
  - anonymouskimmer 4y ago
    It seems to me a bit like scattering a bunch of sand onto a still body of water. The sand hits simultaneously at all points, creating waves that interfere and reinforce each other. Why does the universe have to reconcile? Just let the waves do what they do and move on from that.
    - haneul 4y ago
      The simultaneity and single reference frame of the sand hitting example means there are no contradictions present. Assuming a finite speed limit to information transfer exists, exceeding that limit means you can create a potentially unlimited number of contradictions in state. It would be like watching the waves do what they do, but none of it happened, because no matter what you think you saw, there is at least one contradiction (due to the teleporting meddler). Like if you imagine any one state, and you meddle it to be impossible, as if doing Cantor’s diagonalization on the potential state space (if you can do literally instant teleportation and action with no cooldown).
anamexis 4y ago
Or you can consider the event as "inevitably will happen." Just as valid.

amluto 4y ago

No, it already happened in our frame of reference. Our frame of reference, in special relativity, is a spacelike slice through the universe, “now” is what we would conventionally think of as “now”, and light moves at the speed of light. In general relativity, things get weird and frames are more of a local phenomenon, but as long as you stay away from the event horizon, it’s not that weird.