- #1
benhsmith
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I don't have an extensive physics background, so I apologize if there's a well known or obvious answer to this question.
I'm familiar with the Newtonian version of time in which it's treated as a kind of fourth dimension. So there's x,y,z and t. Sitting here typing this, time is passing for me and I'm moving along some t axis.
I've also read about how things like closed time-like curves would mean that time travel is, theoretically, possible.
Intuitively, it seems to me that if the I and the Earth are moving along a t axis, then even if I could travel back to some previous point on this t axis, when I got there the Earth wouldn't be there anymore. Not just because it would have moved to some new point in three-dimensional space, but because it would have move to a new point in time. So, for example, if t0 is my current moment in time and t1 is, say, some moment in 2009, the physical matter that makes up me and the planet I'm standing on can only exist at t0 or t1, not both. Or, does all matter and energy exist at all points in time that it will ever pass through simultaneously? If it's the latter, how do we know that?
Can anyone recommend a book for non-physicists with a good explanation of how this works?
I'm familiar with the Newtonian version of time in which it's treated as a kind of fourth dimension. So there's x,y,z and t. Sitting here typing this, time is passing for me and I'm moving along some t axis.
I've also read about how things like closed time-like curves would mean that time travel is, theoretically, possible.
Intuitively, it seems to me that if the I and the Earth are moving along a t axis, then even if I could travel back to some previous point on this t axis, when I got there the Earth wouldn't be there anymore. Not just because it would have moved to some new point in three-dimensional space, but because it would have move to a new point in time. So, for example, if t0 is my current moment in time and t1 is, say, some moment in 2009, the physical matter that makes up me and the planet I'm standing on can only exist at t0 or t1, not both. Or, does all matter and energy exist at all points in time that it will ever pass through simultaneously? If it's the latter, how do we know that?
Can anyone recommend a book for non-physicists with a good explanation of how this works?