-----
Original Message ----
From: Regner Trampedach
<art@xxxxxxxxxxxxxx>
To:
geocentrism@xxxxxxxxxxxxx
Sent: Friday, 23 May, 2008 4:54:26 AM
Subject: [geocentrism] Inertia
I am afraid I don't have the time to dig up all the relevant posts and
reply
to them individually. This post, however, should address many issues
raised over the concept of inertia in a range of threads in this forum.
In
Philip Madsen's post, 10/05/2008 he
correctly points out the difference
between "equivalence" and "equality". That is an important distinction.
In physics and astronomy we don't have a habit of redefining words, as
opposed to, say, in politics...
a) Gravity and inertia are
not the same.
b) Gravitational mass and inertial mass, do seem to be the same (no
observations have contradicted this, to date).
c) Inertia cannot be caused by gravity from the distant stars - no
matter how
far away or how the are distributed. The gravitational force from
the
distant stars is minuscule compared to all the other forces we are
subject
to - do the math!
If the Universe (on large scales) has a smooth matter
distribution, the
gravity from all directions will cancel each other. It is obviously
not
completely uniform, so let's explore the other extreme: Only stars
from
one direction, say, a cone of 30° opening angle contribute any
gravity.
The pull from all those stars, back to the beginning of time, would
be
a million-million times feebler than gravity from Earth. If the
Universe
is only 6000 years old (and gravity travels at the speed of light)
the pull
from those stars would be yet another factor of a million times
feebler.
And there is of course the problem about direction. How can the
distant
stars know which way we are trying to move a body, and then counter-
act that motion with a gravitational pull in the opposite
direction. It can't
make sense, whichever way you look at it.
d) Maybe I need to point out that forces are vectors and they are
additive.
That means, that if you have two forces of equal magnitude but
opposite
direction, the nett-force will be exactly zero. And the behaviour
of an
object in that zero nett-force field does not depend in the
slightest on how
that zero came about; whether it be from no forces at all, or from
huge,
but opposing forces. Only the (vector-)sum matters.
e) If gravity created inertial mass, we would be able to predict the
mass of
objects from the law of gravity - we can't! We can only observe and
use
Newton's 2nd law (F = m*a) and maybe the law of gravity or others,
to
infer the mass.
f) There has been other philosophical theories about the distant stars
"somehow"
giving rise to inertia, but no successful physical theory that I am
aware of.
g) The best current candidate for a inertial field, is the Higg's
field, mediated by
the Higg's boson - but there are, of course, competing theories.
The Large
Hadron Collider (LHC) at CERN, opening later this year, should be
able to
detect the Higg's boson if it exists. And the Higg's field would be
a local
field, not depending on the totality of stars in the Universe.
h) Lastly, but very important: We know how inertia works, and not
knowing
why, doesn't really change that. Claiming that classical mechanics
doesn't work
because we don't know where inertia comes from, is therefore
nothing but
obstruction and obfuscation from the issues at hand. Finding out
what gives
rise to inertia is a separate and obviously very interesting
question.
I have tried to address most of the inertial issues that have surfaced
in this forum
lately (I predict that Allen will disagree - I must be a psychic...)
and the verbosity
(I apologize) is due to an attempt at catching some of the most glaring
objections
that could arise.
Regner
