Time

[Joshua C.D. Harrison Stockley]

I Just want to know; what do people think time is; a Vector or a Scalar?

Post with your opinion, I want to see what most people think about this.

 

Ok, to avoid confusion:

A Scalar is a quantity that has only magnitude(size); for example: Distance, Speed, Mass.

A Vector is a quantity that has magnitude(size) and Direction(that it acts in); for example: Displacement, Velocity, and Weight.

 

[Joshua C.D. Harrison Stockley]

in a way I guess you are right, that there are an infinite number of ways of getting to where we are now. The main problem with trying to imagine it is that we only sense things in three dimensions, not four, say for example an ant, it can only see in two dimensions, and so if you were to fire something along the third dimension they would not view it as it was. say for example a ball, all they would see would be an expanding and then contracting circle along the other two dimensions, very difficult to imagine indeed.

[AlexTheNerdyOne]

I look at the difference between vectors and scalars in the way I look at the difference between distance and displacement. i.e. in distance you are measuring how far you have travelled and in displacement you are measuring how far you have travelled from your starting point and in what direction. So I guess before you could define whether time is a scalar or a vector you need to answer the question, do you see time as only going forwards or can you conceive of their one day being the possibility of one day travelling backwards? Because if you define it as only going forwards you would measure it in the way you measure distance because it has a set line it could follow and a set direction so it would be a scalar but (and I may only be thinking this because I have watched way too much doctor who in the lead up to the new season) if you conceive of the possibility of moving both forward and back in time and if you measured how far you had travelled not by the amount (as in I travelled forward 5 years then back ten therefore I have travelled 15 years) but in the more sensible (travelled forward five years then back 10 years so I am 5 years back) then and only then would I define time as a vector because back 5 years gives both a magnitude and a direction. Sorry for how scattered this is but the newest episode of doctor who airs in a few hours and I am in australia so it is late at night and I am excited.

[Joshua C.D. Harrison Stockley]

Ah, but it does not have to have travelled backwards to be considered a vector, only that it is possible for it to travel backwards

[Wayne Dirac]

Well truth be told if you use the euclidian action (not to be confused with euclidian space) in the Feynman path integral formulation of quantum mechanics, then time is a complex variable (meaning it has real and imaginary terms) and from there you can easily see that we are in a Minkowski space, which is a 3+1 dimensional vector space. Hence time is a vector. 

 

In fact, you can interpret solutions to the Dirac equation to mean that anti-particles such as a positron (anti-electron) is just a regular particle traveling backward in time. This led Feynman's thesis advisor, John Wheeler, to develop the one electron theory of the universe. 

[Joshua C.D. Harrison Stockley]

Wait a minute! Are you saying that anti matter could in fact be made up of techion particle!? (particles travelling backwards in time)

[Wayne Dirac]

No, a tachyon is a particle that travels faster than light. Anti-particles don't travel faster than light, they just could be interpreted as regular particles traveling backwards in time. This doesn't mean they are traveling faster than light.

[Joshua C.D. Harrison Stockley]

Ah right I see, even so, that is an interesting concept, although it is difficult to travel backwards in time without exceeding the speed of light, at least so far as I know, although frankly I am only in 6th form, which in america would be about second last year of high school, so I don't know as much as I would like on the subject, but there is nothing that interests more than quantum time theories

[Wayne Dirac]

Ultimately, though, it is just an interpretation of the mathematics. The math clearly says that time is a vector, and you can play with it in quantum mechanics to mean different things.

[Joshua C.D. Harrison Stockley]

Yes, but because it is always treated as a scalar, at least when it is taught, and so people just accept that. I always get the worst answer, it really annoys me because it show how little people think about things,: 'Because it just is' *sigh*

[Wayne Dirac]

Have you taken calculus? Typically you take derivatives with respect to a vector quantity. No one really explains it this way, but it is true. In physics and introductory calculus it is most convenient to take derivatives with respect to time, thus implying that time is a vector. You never see derivatives with respect to something like mass.

[Joshua C.D. Harrison Stockley]

Hmm. you certainly do have a point, I was taught it earlier this year, I guess that you only can derive vectors when dealing with physics I guess. It is interesting to see it from a more mathematical side, being more interested in physics and having a very visual mind I tend not to think about it, although when I do think about things in mathematical ways I tend to come up with rather interesting things, like I have a method to prove Zero is infinity, now it doesn't work, but only someone who knows a lot about the concept of infinity would be able to notice why.

[Joshua C.D. Harrison Stockley]

HA! Short and simple! I LOVE IT!