[Physics] About "logical errors"

[Ilja Schmelzer]

Looks like a post which I have thought was lost do to bad internet has
gone through nonetheless, so sorry that somewhere else I have repeated
the same ideas.

2016-11-02 21:43 GMT+01:00, Arend Lammertink <lamare at gmail.com>:
> Let me just quote Nikola Tesla. From an
> article I wrote earlier:
>
> "I hold that space cannot be
> curved, for the simple reason that it can have no properties. It might
> as well be said that God has properties."

Sorry, not impressed.  Space has properties since Euclidean times,
namely an Euclidean structure, which defines distances. Why should I
care about literature criticism, about what "space is literally"?
Playing with words is not helpful, and it is no more. Because you can
name this thing, which has all these properties, differently.  Say,
Euclidean structure, something not space but existing everywhere in
space.  This would save your theory about "space properties", whatever
it contains, against this criticism without changing anything in the
theory.

> Every action is accompanied by an equivalent
> reaction and the effects of the latter are directly opposite to those
> of the former. Supposing that the bodies act upon the surrounding
> space causing curvature of the same, it appears to my simple mind that
> the curved spaces must react on the bodies and, producing the opposite
> effects, straighten out the curves. Since action and reaction are
> coexistent, it follows that the supposed curvature of space is
> entirely impossible.

Sorry, but "action equals reaction" is a natural consequence of the
Lagrange formalism.  And GR has a Lagrange formalism, thus, there
holds "action equals reaction", appropriately understood.  That
standard quote of "matter tells spacetime how to curve, and spacetime
tells matter how to move" or so.

> Interesting that you bring up the "GPS" subject. I suggest watching
> some of the work of Ron Hatch. He is just about THE expert on GPS and
> he says that GPS pretty much kills the whole theory.

The video has not told me such a thing.  It was more concerned about
energy and so on.  Of course, energy and momentum densities for the
gravitational field are a really strong (and well-know) weak point of
GR.

In fact, if GPS would kill GR, a talk about this would be simple.  One
describes the actual times measured by the satellites, compared to the
times measured by the clocks on Earth, and then compare the numbers
computed by GR and the numbers measured.  Instead, what I have heard,
there were only qualitative claims about what GPS shows, and all these
were in agreement with what I would expect based on GR.