Re: Tom Van Flandern and Newtonian Gravity

From: Bilge (dubious_at_radioactivex.lebesque-al.net)
Date: 08/10/04 

Date: Tue, 10 Aug 2004 06:23:30 -0000

 Tom Van Flandern:

>and "Bilge" <dubious@radioactivex.lebesque-al.net> writes:
>
>> [Bilge]: You wrote down a spacetime metric. If you meant space, then
>you shouldn't have written down a metric which included the time
>direction and gave the distance, ds^2 as the proper time (or proper
>distance). Which is it, tom? Did you mean to say spacetime, or did you
>mean to write down a metric that didn't include time?
>
> Mine was a simple point, perhaps too simple for an advanced
>intellect such as yours. I said (paraphrasing) "curved spacetime has
>nothing to do with curved space". If you had read my article, you would
>see the argument that "spacetime" means proper time, and has no space
>component.

  Which article, tom? Let me compare what you have on your site now,
with the original text from which you claim the article was excerpted.

Current url:

   "Multiplying the coordinate time interval by the speed of light has
   turned time into a space-like coordinate (meaning one measured in
   meters, not to be confused with a "space-like interval" as used in
   general relativity),..."

As published in aperion:

   "Multiplying the coordinate time interval by the speed of light has
   turned time into a space-like coordinate..."

  Later in the article, you clearly mention timelike intervals,
so if you are talking about a timelike interval, how can you not
be talking about spacetime?

>Then you too would see that your whole set of questions above
>and in the remainder of your post make no sense in the context of my
>article because you took the meaning of my words in a completely
>different sense than was intended.
 
  I don't think so, tom. For example, later in that same url, you state:

  ``In this form, we can see the space-time interval ds as a purely
  time-like interval dt that was merely made to look space-like through
  multiplying it by c.''

 And further below that, you state:

 ``This is an important concept. If the curved path of a body through space
 is not caused by a curvature of space, then clearly an external force is
 still required to produce and explain the deviation from straight line
 motion. And some explanation other than curved space is needed to
 understand the equivalence-principle-like property of gravity.''

>> [Bilge]: You wrote down a spacetime metric, therefore you were not
>talking about space [being excluded].
>
> This is a typical case in point. I wrote down a spacetime
>metric to show (a few steps later) that it had nothing to do with space,
>only with proper time.
 
  But a spacetime metric does have something to do with space, tom.
That's why it's called a spacetime metric and not a time metric.
How about using your same argument to explain the schwarzchilld
geometry:

  ds^2 = -(1-2m/r)dt^2 + dr^2/(1-2m/r) + r^2 d\Omega^2

  rather than one which does not contain any mass?

>> [Bilge]: A distance is what the metric measures. That is why it's
>called a metric.
>
> LOL. "Metric" refers to "measure", not to distance.

  We aren't talking about a hamming distance or some other measure
here, tom. We're discussing geometry.
 
>The spacetime metric measures spacetime intervals, not space distances. That
>'s the whole point.

  Unfortunately, the point is what you don't get, as is evident by your
next statement:
 
>If the metric contained a plus sign where it now has a minus, it would
>measure a space distance.

  Which only indicates that you think a euclidean space is somehow
ordained by god as the only ``real'' geometry and can't imagine a
space with a negative sign in the metric.

>But as it stands, it measures only a proper time interval. It has no
>space component, and no space "distance" is involved.
 
  What do you think the space part of the metric measures? What about
the fact that the metric also measures spacelike intervals?

>> {Bilge]: So, in other words, you are trying to tell me that your
>entire argument against relativity boils down to the physics of a units
>conversion constant?
>
> As I have come to suspect, you lack the ability to
>distinguish me from your many other correspondents. I have no "argument
>against relativity". My discussions have been about the physical
>interpretation of the correct equations of relativity.

  Then you need to first try to understand what the equations mean,
physically. You give the distinct appearance of either not understanding
what the equations mean or deliberately attempting to misconstrue them
in order to facillitate your argument about forces.
 

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