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Does everything really 'move' in time? I thought that time is like a film, where nothing moves except the observer. I'm not sure which way it is. If we travel b

• yathern 6y ago
  I have a couple of things to say here that might clear things up! > I thought that time is like a film, where nothing moves except the observer. We are not merely observers of the universe - we are part of it. When we change where (or when) we are in the universe, we change the universe itself. > Also, I never understood the grandfather paradox. Instead of the "go back in time and kill your grandfather" idea, lets keep the scale smaller. Let's go back in time 1 minute, and then smash our time machine. Now, there are two "me"s in this timeline. But energy and matter can't be created out of thin air! Maybe it took a lot of energy to send me back, but that was in the future, and that future is gone, now that our time machine is smashed. We could very well send gold bars back a minute, and double our money! The way you typically resolve this paradox is through keeping infinite timelines. In our example, there's a timeline where we disappeared off the face of the earth, and a timeline where there are two "me"s. They each continue independently. But if there is only a single timeline, we can do all sorts of paradoxical things. > If I travel in the past and change something, wouldn't the change propagate in time at the speed of light? The speed of light is measured in meters per second. Time is measured in seconds. I'm not sure I'm clear on what your suggested propagation looks like.
  • Geee 6y ago
    Well, I'm not sure actually. It seems to require more dimensions for causal events to 'propagate' in time. I was thinking that events can't change the future instantly, because information can't travel faster than speed of light (which is the normal passing of time). So if I travel from million years from the future, it should take million years for the change to propagate to my original future.
• 6gvONxR4sf7o 6y ago
  Imagine one dimensional space. You are a point tracing some path in space over time. That’s how we experience it. But zooming out and looking at the path itself, you are not really a point (moving through space and time), you are a curve in space and time. I’m not trying to talk about ideas of self or anything. Just that the same thing can be described in two ways: as a low dimensional thing changing with respect to another dimension, or a slightly higher dimensional object that just is. Viewed as points changing over time, a solution to the grandfather paradox would be a remarkable coincidence, with everything happening to match up exactly as it had. Viewed as curves in time, a loop is just a loop. There’s nothing remarkable about a circle. You don’t look at a circle and think “gee what a remarkable coincidence that this infinitely fine path crosses itself perfectly. You just go “yup, it’s a circle.” Neither of these is a better picture than the other. Everything (things described as 3D things) does move in time. Everything (described as 4d things) just exists.