Why Does Time Expand? Spacetime Explained

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The discussion centers on the concept of time and its progression into the future, questioning whether this indicates an expansion of spacetime similar to the expansion of space. Participants argue that time does not expand in the same way space does; rather, it flows. The conversation touches on philosophical aspects of time, suggesting that the question of why time flows may not have a definitive scientific answer and could be better suited for philosophical inquiry. The idea of change is highlighted as fundamental to the concept of time, with the assertion that the absence of change would negate the existence of time itself. The circular nature of questioning the cause of change is also discussed, leading to the conclusion that such inquiries may be inherently flawed. The concept of the "arrow of time" is introduced, with references to theories that link it to events from the Big Bang, indicating a breakdown of symmetry. Overall, the dialogue emphasizes the complexity of understanding time and its relationship to change and existence.
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Why are we constantly traveling into the future? Doesn't this suggest that not only space is expanding, but spacetime is expanding as a whole?
 
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epkid08 said:
Why are we constantly traveling into the future? Doesn't this suggest that not only space is expanding, but spacetime is expanding as a whole?
No it does not. A given spacetime does not change under GR.
 
That wasn't my question. Why are we constantly traveling into the future?
 
epkid08 said:
That wasn't my question. Why are we constantly traveling into the future?
Perhaps such a "why" question is better asked in the philosophy section of the forum.

At any rate this has nothing to do with "expansion" of time.
 
I used the word expansion to describe the motion of time moving into the future; There has to be some accepted theory of why time continues to expand, isn't there?
 
Just choosing to use the word doesn't make it right - it isn't an arbitrary choice. You suggested a comparison to the expansion of space. That's not a valid comparison. Time doesn't expand. A better word is flow. Time flows. Why? Dunno. As said, that may just be a matter of philosophy.
 
Flow sounds right because its been used in the context of describing time before. You could just as well describe the movement of time as expanding. (You're not thinking of it in the right way anyways, but that's not the point)

It's hard to believe that there are no theories on this, considering all of the other theories out there; In reality it's not a matter of philosophy.
 
I'm moving this to philosophy, since the topic is not related to Cosmology. You might want to have a read of, say, The River of Time by Igor Novikov: it's quite a good book on the nature of time.
 
Time is a mental representation of change; some say that time is a "measurement" of change. The complete absence of any change anywhere in the universe would mean no time, so a more fundamental question is: why does change happen?

The question "why" asks for a cause. But if a cause for change ever existed then it would be the cause for a change from the universe going from a state of "no change" into a state of "some change". Of course, this would already be a change, so the cause would not really be a cause of change since such a change is already assumed in the question. This circular assumption invalidates the question. A cause of change cannot be stated, so a cause for time cannot be given either. The question simply does not apply to change (and time).

See a similar discussion about https://www.physicsforums.com/showthread.php?t=171193" Asking for the cause of existence asumes that such a cause could exist already, which makes this question meaningless as well. Existence and change are both undeniable and "why-proof" realities.
 
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epkid08 said:
Why are we constantly traveling into the future? Doesn't this suggest that not only space is expanding, but spacetime is expanding as a whole?

What you are referring to is the "arrow of time".

Acc. to some physicists this is caused by the breakdown of a symmetrie which happened at the big bang.
 

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