The Relation between Matter and the fabric of Space-Time

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Summary:

A discussion regarding how matter behaves when it's part of something like the Space-Time continuum.

Main Question or Discussion Point

I was having a discussion with someone, regarding whether Time Travel was possible. The opposing individual argued that people are composed of matter that is simply woven into the fabric of space-time, therefore, rendering us unable to travel through time. I wasn't sure if he was right because I thought to myself that if we are part of a four-dimensional, space-time, then we'd still be able to traverse time. I mean assuming we knew how to create a wormhole and how to keep it open (say like with exotic matter) and we had a method of travelling through it safely, then we could travel through both time and space. With a wormhole we could have a passage to a different point in space-time. We'd still be part of the same space-time continuum after doing so.

But I don't have enough information regarding this matter and I wanted to hear more regarding the relation of matter and space-time.
 

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PeterDonis
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The opposing individual argued that people are composed of matter that is simply woven into the fabric of space-time, therefore, rendering us unable to travel through time. I wasn't sure if he was right because I thought to myself that if we are part of a four-dimensional, space-time, then we'd still be able to traverse time.
Both you and the opposing individual are using the vague term "travel through time", which is not a good term.

Spacetime is a four-dimensional geometry. Individual observers have worldlines, which are curves in this four-dimensional geometry. Each instant of the observer's experienced time corresponds to a point on their worldline. As the observer's experienced time passes, you can think of the observer as "moving" along their worldline from points with earlier experienced times to points with later experienced times. This could be viewed as "traveling through spacetime" (not "traveling through time"), and if it is so viewed, it is unavoidable; you can't avoid traveling through spacetime because you can't avoid moving along your worldline from points with earlier experienced times to points with later experienced times.

There are mathematical solutions to the equations of General Relativity that contain closed timelike curves, which means possible worldlines for observers that are closed curves, so the observer can return to a point in spacetime multiple times, while their experienced time still continues to move "forward". Spacetimes with wormholes can have closed timelike curves in this way (though not all of them do). At least, that's what happens geometrically; whether it makes sense physically is another matter, and most physicists think it doesn't, i.e., that closed timelike curves cannot occur in our actual universe.

With a wormhole we could have a passage to a different point in space-time.
You are always passing to a different point in spacetime. That's what moving along your worldline means.

Actually, "time travel" would mean going back to the same point in spacetime multiple times (as the description of closed timelike curves above makes clear). But, as noted, most physicists believe this is not possible in our actual universe.
 
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I finally found the great Tom Weller's "Fabric of Space-Time":

1591651843258.png


He's a genius.

Getting back to the topic at hand, I think you need to be a lot more clear and specific about what you are talking about. What does it mean to "traverse time" and how does it differ from our everyday experience of time, where we move along at one second per second.
 
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