What are the Requirements for Time to be Considered a Vector?

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Discussion Overview

The discussion centers on whether time can be considered a vector, exploring theoretical implications in physics, particularly in the contexts of relativity and Newtonian physics. Participants examine the characteristics of vectors and how they apply to the concept of time.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants argue that time cannot be a vector because we cannot go back in time, which they believe violates vector rules.
  • Others assert that in the framework of relativity, time is indeed a component of the spacetime 4-vector, suggesting that it can be treated as a vector under certain conditions.
  • One participant mentions that time can be treated as either a scalar or a vector depending on the theoretical framework, emphasizing the importance of matching formulations to observations.
  • There is a discussion about the properties of vectors, including the necessity for them to follow laws of addition and subtraction, with one participant questioning the implications of negative time values.
  • Another participant clarifies that the inability to "go" backwards in time does not preclude time from being a vector, suggesting that negative time could simply indicate a sequence of events.

Areas of Agreement / Disagreement

Participants express differing views on whether time can be classified as a vector. While some support the idea based on relativity, others maintain that it does not meet the criteria for vectors due to the inability to reverse time. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference various theoretical frameworks, including relativity and Newtonian physics, without reaching a consensus on the classification of time. The discussion highlights the complexity of defining time within different physical theories and the implications of such definitions.

romsofia
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Is time a vector?

I don't think so, because we can't go back in time therefore it can't follow vector rules.

However, I'm not sure this works in all cases (such as in a cases where v is close to c).

Thanks for the help.
 
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In relativity, time is one component of the spacetime 4-vector.
Also, it is theoretically possible to go meet your former self according to general relativity.
 
You can make time a scalar or a vector in a particular theory...the test is whether such a formulation matches observations and leads to any predictions. Is it useful??

While time is a vector in relativity it is not in Newtonian physics.

...because we can't go back in time therefore it can't follow vector rules.

A vector has magnitude and direction...it doesn't have to point everywhere nor is our ability to "go" with a vector a criteria...for example, you also cannot "go" where an acceleration vector does.
 
BruceW said:
In relativity, time is one component of the spacetime 4-vector.
Also, it is theoretically possible to go meet your former self according to general relativity.

Oh I think I've seen that somewhere, but I thought we took the time out. E.G. {S(x,y,z,t)} and then we did something like {S(x,y,z)*e^{-i\omega t}} but I doubt that is what you're talking about haha.

Anyway, thanks for the help!

Naty1 said:
A vector has magnitude and direction...it doesn't have to point everywhere nor is our ability to "go" with a vector a criteria...for example, you also cannot "go" where an acceleration vector does.

A vector also has to follow basic laws (addition, subtraction, etc). If you can't go back in time, then you can never have a negative time value which is possible following the laws of subtraction.For example, {C=B-A} with {B=1} and {A=2} then {C=-1} which wouldn't make sense to me.

Anyways, thanks for your input and help!
 
romsofia said:
Oh I think I've seen that somewhere, but I thought we took the time out. E.G. {S(x,y,z,t)} and then we did something like {S(x,y,z)*e^{-i\omega t}} but I doubt that is what you're talking about haha.

Anyway, thanks for the help!

No problem. It looks like you're talking about some quantum energy eigenstate. This can't be done for a general quantum state. Also, I was talking about relativity, not quantum mechanics.
In relativity, we can talk about each spacetime event being specified by 4 components (i.e. a 4-vector). We only know which is the time component when we define it ourselves. So time is not a separate entity from space in relativity.
 
BruceW said:
No problem. It looks like you're talking about some quantum energy eigenstate. This can't be done for a general quantum state. Also, I was talking about relativity, not quantum mechanics.
In relativity, we can talk about each spacetime event being specified by 4 components (i.e. a 4-vector). We only know which is the time component when we define it ourselves. So time is not a separate entity from space in relativity.

Brain fart on my part haha, I guess when I was typing that I forgot that you were talking about general relativity >.<!

Thanks for all the help though, I have little knowledge of relativity so I guess I have to start studying some of it :D!
 
romsofia said:
A vector also has to follow basic laws (addition, subtraction, etc).
The laws that a vector must satisfy are listed here.
http://en.wikipedia.org/wiki/Vector_space#Definition

There is no requirement that you be able to "go" backwards in time for time to be a vector. A negative time simply means that one thing happened earlier than another.
 

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