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Re: Nothing Can Move in Spacetime

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Posted by Nemesis on April 21, 19101 at 17:03:32:

In Reply to: Re: Nothing Can Move in Spacetime posted by ReillyAtkinson on April 21, 19101 at 12:00:15:

Reilly Atkinson wrote:

>Sir -- Just for the record, I'm a retired physics
>professor. That some professional physicists agree with
>your, shall we say, peculiar, ideas does not mean much.

In that case I feel sorry for you professor. There are high school students who have no trouble understanding that nothing can move in spacetime. And I personally know of quite a few physics professors who disagree with you. In fact I get emails from them continually. So if it comes to a political fight, I think you will loose in the end. Although I must say that I do get a lot of vitriolic hate mails.

>I, for one, find huge errors and mistakes in your
>arguments and position. Let me count the ways.

Ok. Let's take a look at those "huge mistakes".

>First simple: most of us in the physics trade go with
>Einstein, and consider time to be measured by clocks. I
>might add that this approach has worked pretty well for a
>long time.

Why are you saying this? Are you implying that I am against relativity? With all due respect, this is a strawman of your own making.

>Now, about the dimensionality stuff. That time is
>considered a dimension is purely a utilitarian idea. That
>is, we presume that time is measured by real numbers,
>hence is represented by the continuum, which,
>conventionally, is considered to be a 1D object. Doing the
>dimension thing is purely a matter of mathematical
>convenience, no big deal.

Is this why Dr. Thorne and Dr. Hawking believe you can travel in time? How can they do so if they believe that time is an abstract mathematical thing? It looks to me like they believe in motion in a physical spacetime. How else can you travel in time if you don't believe that there is an actual time dimension?

>Go to any freshman physics text, and find a chapter on how
>we describe motion. Well, how about the fact that you will
>undoubtedly find a plot, with distance along the x axis,
>and time along the y axis. Further you will see plotted a
>line, with dx/dt nonzero. Voila, motion in space-time
>directly demonstrated. That's all she wrote.

No, that only demonstrates motion in space.

>Also, in your website you have some argument that deals
>with 4-vectors and dt/dt. Well, sir, you are quite
>inccorect on this matter. The position 4-vector used by
>knowledgeable physicists is (ct,x,y,z), not (t,x,y,z). So,
>your dt/dt argument is totally without merit -- you got
>the dimensions wrong. Most of us learn in freshman physics
>that it is important to take great care with dimensional
>consistancy -- we teach it also.

'ct' is a tool that is used to change the time axis from seconds to meters. It is especially useful to demonstrate the light cone aspect of a path (world-line) in spacetime. In no way does it change the time dimension into a spatial dimension. And it certainly does not prove motion in spacetime or in a time axis.

>Finally be aware of a bit of history - that quite
>undermines your assertions. Einstein's initial work was
>not what we call covarient -- time and space were on
>somewhat of a different footing(did not do too much with
>d/dx, but did quite a lot with d/dt, sort of)Now,
>Minkowski ( and I think Weyl as well) realized the
>practical, practical, PRACTICAL, practical virtues of
>using 4 dimentional space time for the math of relativity.
>Covarience was thus born, without which QFT would be
>impossible. Goodness gracious, in many respects Maxwell
>and Lorentz and Poincare all bounced in and out of space
>time, as do freshman physics texts.

Sorry but I see nothing in the above that argues for motion in spacetime.

>To most physicists it is quite obvious that objects move
>in space time, or, for that matter, in space.

Most physicists may assume that things move in spacetime but those who are willing to put a little bit of thought into it, know motion in spacetime is an impossibility.

>Space and time are conventions, inventions, after all,
>used to describe motion. We could not ply our trade if
>what you say is true.

Not at all. What I say is 100% correct. Spacetime is an abstract, static collection of events. World-lines are static and events do not move from one position in spacetime to another. Deny at your own detriment.

>And, if you were correct, then we would simply adjust our
>descriptive notions to rectify the awkward situation you
>claim to be true.

If I am right (which I am) then it makes a lot of people look foolish, including some of the most celebrated physicists in the world.

>And, if you wish to push your ideas, at least get the
>basics correct -- (t,x,y,z) certainly drove me away. Why
>read stuff that's wrong?

I disagree that it is wrong. It is a perfectly legitimate way of representing a 4-vector position in spacetime. Again, 'ct' does not suddenly change the time dimension into a spatial dimension. It is a convenience tool only. Besides it supports my stance that there can be no motion in time because the time dimension is transformed into a spatial dimension that is no longer measured in seconds ut in meters, a length unit. I have always maintained that there is a need for a fourth spatial dimension such that a particle's true 4-velocity is expressible thus:

(dw/dt,dx/dt,dy/dt,dz/dt) which becomes (c,dx/dt,dy/dt,dz/dt)

There is motion at c in the fourth spatial dimension for all particles. Motion in a time dimension is crackpottery.

Nemesis

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