Re: "Is There a Force of Gravity?"



On Nov 27, 2:11 pm, Tom Roberts <tjroberts...@xxxxxxxxxxxxx> wrote:

There are literally hundreds of experiments that support and confirm SR,
and many of them refute Newtonian mechanics. Look in the FAQ for references.

This is not true. There are no experiments out there that completely
support SR. However, there are plenty of experiments out there which
agree with the Lorentz transform but not its immediate reciprocal form
which is also the Lorentz transform. To agree with SR, you need an
experiment that show both the Lorentz transform is true as well as its
reciprocal form. <shrug>

There are dozens of experiments that support and confirm GR, and most if
not all of them refute Newtonian mechanics. Look in the FAQ for references.

Most of all these experiments are faulty. For examples,

** The eclipse expeditions of 1919 by Sir Eddington was a total joke.
The current assumption that the geodesic follows the path with the
maximal accumulated spacetime predicts photons cannot move through
space. Dr. Taylor's derivation of photon deflection assumed the
geodesic following the path of least accumulated time which is in
direct violation of the current assumption.

** Shapiro effect and its later derivatives involves with accuracy
without interference of the observed signal and the reference signal.
It cannot be seriously considered as any scholarly work.

** Assuming the geodesic follows the path of maximal accumulated
spacetime comes close to the actual observation. However, if geodesic
follows the path of minimal accumulated time, the prediction becomes
way out in the ball park.

But ultimately the equations of motion come from the Einstein field
equation:

G = T G is the Einstein curvature tensor, and T is the
energy-momentum tensor; units are such that c=1
and 8*pi*k=1, k is Newton's gravitational constant.

The Einstein field equations only allow one to solve what the metric
is. These equations do not deal with the geodesics directly.

This deceptively simple-looking equation is incredibly difficult to
solve except for simple systems with lots of geometric symmetries; your
spring-mass system has no such symmetries and is well beyond anybody's
ability to solve, or even instantiate the general equation to the problem.

They are actually not difficult to solve if assuming a diagonal metric
in spherically symmetric coordinate system where the orbital motion is
confined to the equatorial plane. However, it is rather tedious to go
through the Ricci tensor, and you have to do so with all four variables
of spacetime at the same time. By modifying the Newtonian law of
gravity could easily achieve the same result. All that work for very
little to show for. <shrug>

The metric is itself the interpretation matrix to the measurement (the
coordinate itself). Only the combination of the interpretation and the
measurement makes up a complete observation of reality. Since the
measurement is coordinate dependent, the interpretation must be
coordinate dependent as well in order to observe the reality in which
the reality must not be coordinate dependent. Ricci tensor based on
the Riemann curvature tensor works with the interpretation matrix or
the metric. The Riemann curvature tensor is a man-made gage designed
by Ricci to characterize the curvature in space and later on in
spacetime. By doing that, this fault in modern differential geometry
allows the Einstein field equations to yield an infinite number of
solutions. Oh, don't feel so hopeless now. After finding just one
solution, the others can be derived very easily.

One can, however, work in an approximation to GR, as long as the mass
and spring are of less than planetary size and their motion is much
slower than c; the approximation is the same as Newtonian mechanics, and
you can use the usual Newtonian equations.

Right, GR is so complicated that Newtonian model must be wrong
[philosophically speaking]. <shrug>

.

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