RandaMinor
More options Jul 9 1999, 11:00 pm
Subject: Gravity and Newton's third law
From:
randami...@aol.com (RandaMinor)
Date: Sat, 03 July 1999 06:54 PM EDT
Message-id: <
19990703185444...@ng-fr1.aol.com>
Question:
Aside from the gossamer torsion balance work of H. Cavendish, have we
experimentally quantified a magnitude of force that can unequivocally
be
attributed to a force of gravity, absent the assumptive calculational
use of
Newton's third law?
Consider: A balance scale functionality arises from the same principle
as the
equivalence of free fall acceleration across mass magnitudes From
this we can
discern inertial and rest mass magnitudes of terrestrial objects.
However, our
measure of gravity (the force we attribute to mass), is taken solely
in terms
of our own weight, and/or, quantified against the rest mass of local
terrestrial objects.
We can use Newton's second law [F=ma] and determine the
magnitudes of force required for various locally oriented operations,
including
the necessary propulsion required to place various mass magnitudes in
orbit.
Economic motion and the principle of least action appear to be common
aspects
across all stable frames of reference. The orders of form created by
the action
in stable systems are similar. Consequently, we can generally, by
invocation of
Newton's third law, apply our quantification of local terrestrial
mass
magnitudes to the solar and celestial frames. With Newton's third we
can
utilize the similar economic orders of form that are common to stable
frames of
reference in general, and assign a mass to the planets and sun, based
on a
time-distance proportionality measured against the kinematics of mass
motion at
the local frame, increasing the local inertial or rest mass magnitude
accordingly, and applying it to the sun or planets etc.
So essentially what we are doing is making a determination of
otherwise unknown
stable system mass magnitudes, based on the time distance
characteristics of
the orbits at the stable terrestrial and solar frames.
This aspect of Newtonian thought is revered today, as one of his most
brilliant and powerful ideas, and is the basis for our universal
application of
gravity to all objects in the universe. And absent any direct
evidence to the
contrary, there is no compelling reason for us to drop this assumptive
generalization.
The problem that presents itself, to my way of thinking is this: The
equivalence of free fall across mass magnitudes allows us to place any
mass
magnitude into any orbit, with consideration for the value of [r] and
[v] and
the free fall component of {a}, which derives from the similar
economics of
stable system orders of form in general.
The force required to overcome the pull at surface Earth, naturally
varies according to the relative masses of the local objects. However,
an object's mass is not relevent to its orbital path, once in place,
for the same reason it is not relevent to its rate of free fall. In
fact, if we could determine an unknown object's mass, from its orbital
trajectory alone... there could be no free fall equivalence across
mass magnitudes at surface Earth. So the idea that [Ma=mA] seems to be
invalid as a matter of physical principle.
Where is the flaw in this process of reasoning?
Thanks for any light you can throw on this for me.
RandaMinor (
randami...@aol.com) wrote:
: [snip]
: However, an object's mass is not relevent to its orbital path,
: once in place, for the same reason it is not relevent to its rate
of free
: fall.
That is only true for masses much less than that
of the moon, a satellite cannot follow the same orbit as
the moon.
: In fact, if we could determine an unknown object's mass, from its
orbital
: trajectory : alone... there could be no free fall equivalence
across mass magnitudes at
: surface Earth. So the idea that [Ma=mA] seems to be invalid as a
matter of
: physical principle.
:
: Where is the flaw in this process of reasoning.
I have posted it in sci.physics "Gravitational Formulae I"
and also II and III. There are several reasons, and much
to cover, if you can't find the 3 or 4 articles in dejanews,
email me.
Regards,
name withheld absent author's permission
randaminor writes>
I am reposting this because I received only one response to my
question. I am
including the response. My first reaction to the answer was shock. I
wondered
how such a piece of information had gotten by me. So I tracked the
recommmended
posts down as regards gravitational formulae1,2 and 3. I have gone
over them
thoroughly and now realize that what the one response was referring to
is that
objects do not fall at precisely the same rate, although locally, the
difference is so small that it causes no practically measured
difference..
Consider the question I posed and the answer I received. The answer
seems to
say that this precise question has been entertained and resolved, and
the
information can be found in past newsgroup discussions. But what I
found in
these discussions only dealt with the accuracy of the gravitational
equation
from the perspective of two frames of reference, Newtonian and GR.
Hindsite has taught me how easy it is for the great minds to overlook
the
simplest evidence. Take Aristotle and his teaching that heavier
objects fall
faster than lighter objects. For hundreds of years this was the
accepted dogma.
The balance scale had been in use since well before the time of
Aristotle. A
small amount of concentration will tell you that if the balance scale
works...
objects must fall at the same rate. Yet in all of humanity, the
correct answer
had to wait for Galileo.
So I went to original principle. The source and beginning of the base
for our
paradigm concerning gravity. And discounting the minor discrepancy,
logically
developed the ideas into a sequence of English words that led to a
contradiction. But, I was searching for this contradiction due to my
suspicion
of Newton's third law in the first place. Its a very simple
contradiction and
had Newton been confronted with it at the time he wrote the Principia,
he would
have had to explain it, to justify the third law.
According to what I am hearing from ___ _____ and another newsgroup
user via email, the solution is to be found in the relativistic math.
As most of you know, Einstein based his theory in part, on the
equivalence
between inertial and gravitational mass. He called it unexplained in
the
Newtonian frame, and carried it over into the GR frame, by postulate.
Einstein
used the phrase that included "proportional to" as its equivalence
identifier.
Willard Gibbs one of the first truly great American physicists, had
been more
reserved. He used the phrase "proportioned to". The fact as I see it
is this,
gravitational mass is defined in terms of inertial mass. So, by
definition and
by definition only, they are equivalent. Inertial mass is proportioned
to Gravitational mass. We describe what we feel as weight as a
property of every mass and its relation to every other mass in the
universe. The vehicle that makes this work, mathematically, is the
economic behavior common to all stable systems.
The principle of least action describes similar orders of form across
stable
systems. The one stipulation that is required in order to access this
universal
conveyer that applies our local inertial mass quantification to the
rest of the
universe, is Newton's third law.
Absent the theory of relativity no one has offered any response to my
question.
But GR is based on the defined equivalence between gravitational mass
and
inertial mass. A principle that prohibits the generalization of
Newton's third
law. The answer I received states that Newton's F=ma was not accurate
where the
GR equation is. Newton's equation speaks to a measurable physical
quantity, the
accuracy of which is not precise. Einstein's equation speaks to a
precise
equivalence by postulate. Any errors in Newton's picture of the world
reflect
the minor variations in stable system motion, in terms of Kepler's
conics, such
as the orbit of Mercury and its precession. But consider, if we were
to
proportionally increase the size of all the planet orbits, the larger
we go,
the less significant is the precession.
So take Kepler's conic into the time dimension where the planet period
is set
equivalent to the distance light travels in the interval, and we have
one very
long helix, a regular order of form, that is so long as to almost be a
straight
line. We can expect a greater precision because of the extrapolation
in time,
and the original premise of equivalence.
So the GR people want to keep the equivalence, which denies Newton's
third law
as a matter of principle, and keep the third law too. Because the
predictions
of GR have been proved countless times, and because it is more
accurate than
Classical Mechanics. This is not sufficient reason to maintain a
flawed
conceptual view of the universe. The mathematics can function just as
well, if
not better, if accompanied by a correct interpretation.
The lensing of light near the Sun was held to show that light is
affected by gravity in that it
follows the space curvature that increases in the proximity of large
masses.
The elevator with occupants who cannot tell the difference between
acceleration
and gravity is even used as a thought experiment to show the
reasonableness of
the postulate. But the price for constant acceleration comes high. I
think the
elevator people would start to suspect that something other than
gravity was at
work as they started to crush under their own weight. And the limit on
velocity
set at the speed of light is a pretty safe limit, (actually for around
21 days) and should be proved over and over and over.
Any mathematical manifold that includes time as a dimension and
extracts a
regular conic to a helix through that dimension, can define the
generally
invariant extrapolated curve as a property of space. Whether you call
it the
result of the curvature of space or the universal attraction between
masses
depends solely on the mathematical frame of refernce you use to
analyze it. In
all cases it reduces to an order of form that describes or is
described by, the
principle of least action.
I don't think we can justify Newton's third law simply be declaring
the
principle that invalidates it as the basis for the justification. I'm
just a
self trained country boy, but I believe I have put something forward
that
deserves a little bit more than a mere wave of the hand.