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> 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. Ot

by xwdv 4y ago

> 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. Those representations are inaccurate. If time is truly frozen, that means photons should be frozen in place, unless photons are somehow exempt due to having no mass and thus no time. If the frozen photon theory is correct, you would have to see things by moving your eye into rays of light and letting photons hit your receptors and get consumed. But because these photons are being consumed and not replaced, you will leave pockets of darkness where your eyes will see no signal if you pass through there again. At normal everyday distances you will see everything frozen in place with this method. However, at long distances such as light years, moving into the light source will run its animation over time at the speed you are moving toward it. So you will see the event occur before your eyes right up until you reach the destination where the event has already occurred, and you can observe firsthand what we already knew to be true.

anonymouskimmer 4y ago
> Those representations are inaccurate. Yes, I know Sci Fi and fantasy are inaccurate depictions of reality. > So you will see the event occur before your eyes right up until you reach the destination where the event has already occurred, and you can observe firsthand what we already knew to be true. I get this. I just don't get how moving faster than the speed of light (or causality) necessarily invokes literal time travel. And while I've read that physical scientists are amazed at how well mathematics model and predict reality, if this time travel is a result of the mathematics, then I need to be convinced that in this case the mathematics really are modeling reality.
- xwdv 4y ago
  Look at it this way, let’s say you’re at the event site and seeing it happen right in front of you. Suddenly, some travelers arrive and say they also came to witness the event, but they came from light years away. How? The light of the event would have only traveled for a few light minutes, and no other type of information would travel faster than that. There’s no way someone light years away would know about it yet. The only explanation, assuming they didn’t perfectly predict the event, is that they time traveled. From your perspective they covered a distance of light years in the span of time between the event’s start and you first meeting them.
  - anonymouskimmer 4y ago
    Sure. But assuming time is traveling the same for you, their origin point, and the photons going between the two, they won't suddenly appear when the event has just begun, even if they travel instantaneously. Because, as you say, the point at which they first saw the event had yet to receive the light image of the event. And if they do seem to suddenly appear much faster than you would believe possible, you suddenly know that you're at the bottom of a time-dilation gravity well (or the equivalent). Though you probably could have figured this out beforehand from the red-shift of the light traveling between the two points. Or you know that they observed the event from a closer point of view, instantaneously traveled to a most distant location to change clothes, and then traveled again to your location. Time travel is only one of at least three possibilities.
    - xwdv 4y ago
      If you are in a time dilation gravity well, the mere act of outsiders traveling into it might be time travel itself, as they are traversing the well from the outside (what you would think of as the future) to reach a point inside where time is lagging behind.
      - anonymouskimmer 4y ago
        Time may be lagging behind, but you aren't traveling backward in it. Merely transitioning to a slower tick-tock cycle.
        xwdv 4y ago
        So in that case traveling into the heart of the well would feel like you are fast forwarding the events of the well until you gradually synchronize with the tick cycle and things move at normal speeds? In which case you could never reach the exact moment of the event you set out to see.

by xwdv 4y ago

anonymouskimmer 4y ago

> Those representations are inaccurate. Yes, I know Sci Fi and fantasy are inaccurate depictions of reality. > So you will see the event occur before your eyes right up until you reach the destination where the event has already occurred, and you can observe firsthand what we already knew to be true. I get this. I just don't get how moving faster than the speed of light (or causality) necessarily invokes literal time travel. And while I've read that physical scientists are amazed at how well mathematics model and predict reality, if this time travel is a result of the mathematics, then I need to be convinced that in this case the mathematics really are modeling reality.

xwdv 4y ago
Look at it this way, let’s say you’re at the event site and seeing it happen right in front of you. Suddenly, some travelers arrive and say they also came to witness the event, but they came from light years away. How? The light of the event would have only traveled for a few light minutes, and no other type of information would travel faster than that. There’s no way someone light years away would know about it yet. The only explanation, assuming they didn’t perfectly predict the event, is that they time traveled. From your perspective they covered a distance of light years in the span of time between the event’s start and you first meeting them.
- anonymouskimmer 4y ago
  Sure. But assuming time is traveling the same for you, their origin point, and the photons going between the two, they won't suddenly appear when the event has just begun, even if they travel instantaneously. Because, as you say, the point at which they first saw the event had yet to receive the light image of the event. And if they do seem to suddenly appear much faster than you would believe possible, you suddenly know that you're at the bottom of a time-dilation gravity well (or the equivalent). Though you probably could have figured this out beforehand from the red-shift of the light traveling between the two points. Or you know that they observed the event from a closer point of view, instantaneously traveled to a most distant location to change clothes, and then traveled again to your location. Time travel is only one of at least three possibilities.
  - xwdv 4y ago
    If you are in a time dilation gravity well, the mere act of outsiders traveling into it might be time travel itself, as they are traversing the well from the outside (what you would think of as the future) to reach a point inside where time is lagging behind.
    - anonymouskimmer 4y ago
      Time may be lagging behind, but you aren't traveling backward in it. Merely transitioning to a slower tick-tock cycle.
      - xwdv 4y ago
        So in that case traveling into the heart of the well would feel like you are fast forwarding the events of the well until you gradually synchronize with the tick cycle and things move at normal speeds? In which case you could never reach the exact moment of the event you set out to see.