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From: GSS on 31 Jul 2010 04:58
On Jul 30, 6:52 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
> GSS wrote:
>> Let us assume that the gravitational mass of a planet is m_g and its
>> inertial mass m_i, such that the ratio m_g/m_i = k. [...]
>
> This does nothing. If k is the same for all objects, it can ALWAYS be set to 1
> by a suitable choice of units and/or the constants in the equations.
>
No, this is not quite true. Let us assume the gravitational mass m_g
is 0.9 times the inertial mass m_i for all bodies (i.e. k=0.9). There
is no way whatsoever, that you can make the gravitational mass m_g
equal to the inertial mass m_i (i.e. k=1), simply by choice of units.
What I had shown in the previous post was that this k could be
absorbed in the universal gravitational constant G so that we could
only deal with the inertial mass m_i in equations.

> IOW: the equivalence principle does NOT imply "k=1" as you seem to think, it
> merely implies that k is the same for all objects.

Strictly speaking, equivalence principle does imply "k=1" as well as
"same value of k" for all bodies. But in practice, as shown in my last
post, value of k different from 1 cannot be distinguished or
established from the "observations of the motion of planets", as long
as "same value of k" is applicable for all bodies. I agree that in GR,
"same value of k" does suffice to grant validity to the equivalence
principle.

GSS
From: nuny on 31 Jul 2010 05:36
On Jul 26, 5:28 am, Pentcho Valev <pva...(a)yahoo.com> wrote:
> If an infinitely long object can be trapped inside an infinitely short
> container, and if an Einsteinian travelling with the rivet sees the
> bug squashed while the bug sees itself alive and kicking, then the
> Michelson-Morley experiment confirms Einstein's relativity and refutes
> Newton's emission theory of light:

If as you say the speed of light is not constant, let's posit
dropping a battery-powered radio transmitter straight down along its
antenna's line-of-sight toward a convenient plane reflector

Pulse it one time while it's falling at some fraction of c, let's
call it dv. Afterward the antenna is basically just a mirror.

There's a clock midway up that releases the transmitter and later
tells it to pulse, and also tells us at the bottom when all this
happens.

When do we first see photons arrive at the reflector?

If velocities add the way you say they do...

The first pulse of photons travels downward at c +dv, hits the plane
reflector and returns upward still at c+dv. It hits the transmitter
antenna *and bounces off*, adding the now-greater transmitter's
velocity to its own, heading down faster than the original photons.
For a smaller distance. This repeats until the many-times-reflected
photons have (as far as we can measure) infinite speed.

That a problem for you?


Mark L. Fergerson
From: Tom Roberts on 31 Jul 2010 10:34
GSS wrote:
> On Jul 30, 6:52 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
>> GSS wrote:
>>> Let us assume that the gravitational mass of a planet is m_g and its
>>> inertial mass m_i, such that the ratio m_g/m_i = k. [...]
>> This does nothing. If k is the same for all objects, it can ALWAYS be set to 1
>> by a suitable choice of units and/or the constants in the equations.
>>
> No, this is not quite true. Let us assume the gravitational mass m_g
> is 0.9 times the inertial mass m_i for all bodies (i.e. k=0.9). There
> is no way whatsoever, that you can make the gravitational mass m_g
> equal to the inertial mass m_i (i.e. k=1), simply by choice of units.
> What I had shown in the previous post was that this k could be
> absorbed in the universal gravitational constant G so that we could
> only deal with the inertial mass m_i in equations.

Yes. That's what I said.

Experimentally, there's no way to separate k from G. So we use a single mass and
the appropriate G for that.


>> IOW: the equivalence principle does NOT imply "k=1" as you seem to think, it
>> merely implies that k is the same for all objects.
>
> Strictly speaking, equivalence principle does imply "k=1" as well as
> "same value of k" for all bodies.

No,it does not. The equivalence principle states that in the local limit one
cannot distinguish between a gravitational field and an externally-applied
acceleration. It says nothing about the value of k, but does require it to be
the same for all objects.


Tom Roberts
From: Henry Wilson DSc on 31 Jul 2010 18:36
On Sat, 31 Jul 2010 02:36:51 -0700 (PDT), "nuny(a)bid.nes" <alien8752(a)gmail.com>
wrote:

>On Jul 26, 5:28�am, Pentcho Valev <pva...(a)yahoo.com> wrote:
>> If an infinitely long object can be trapped inside an infinitely short
>> container, and if an Einsteinian travelling with the rivet sees the
>> bug squashed while the bug sees itself alive and kicking, then the
>> Michelson-Morley experiment confirms Einstein's relativity and refutes
>> Newton's emission theory of light:
>
> If as you say the speed of light is not constant, let's posit
>dropping a battery-powered radio transmitter straight down along its
>antenna's line-of-sight toward a convenient plane reflector
>
> Pulse it one time while it's falling at some fraction of c, let's
>call it dv. Afterward the antenna is basically just a mirror.
>
> There's a clock midway up that releases the transmitter and later
>tells it to pulse, and also tells us at the bottom when all this
>happens.
>
> When do we first see photons arrive at the reflector?
>
> If velocities add the way you say they do...
>
> The first pulse of photons travels downward at c +dv, hits the plane
>reflector and returns upward still at c+dv. It hits the transmitter
>antenna *and bounces off*, adding the now-greater transmitter's
>velocity to its own, heading down faster than the original photons.
>For a smaller distance. This repeats until the many-times-reflected
>photons have (as far as we can measure) infinite speed.
>
> That a problem for you?

No problem.
That's exactly what would happen....but if you do the sums you will see the
practical limitations.

> Mark L. Fergerson


Henry Wilson...

........Einstein's Relativity...The religion that worships negative space.
From: nuny on 31 Jul 2010 21:44
On Jul 31, 3:36 pm, ..@..(Henry Wilson DSc) wrote:
> On Sat, 31 Jul 2010 02:36:51 -0700 (PDT), "n...(a)bid.nes" <alien8...(a)gmail..com>
> wrote:
>
>
>
> >On Jul 26, 5:28 am, Pentcho Valev <pva...(a)yahoo.com> wrote:
> >> If an infinitely long object can be trapped inside an infinitely short
> >> container, and if an Einsteinian travelling with the rivet sees the
> >> bug squashed while the bug sees itself alive and kicking, then the
> >> Michelson-Morley experiment confirms Einstein's relativity and refutes
> >> Newton's emission theory of light:
>
> >  If as you say the speed of light is not constant, let's posit
> >dropping a battery-powered radio transmitter straight down along its
> >antenna's line-of-sight toward a convenient plane reflector
>
> >  Pulse it one time while it's falling at some fraction of c, let's
> >call it dv. Afterward the antenna is basically just a mirror.
>
> >  There's a clock midway up that releases the transmitter and later
> >tells it to pulse, and also tells us at the bottom when all this
> >happens.
>
> >  When do we first see photons arrive at the reflector?
>
> >  If velocities add the way you say they do...
>
> >  The first pulse of photons travels downward at c +dv, hits the plane
> >reflector and returns upward still at c+dv. It hits the transmitter
> >antenna *and bounces off*, adding the now-greater transmitter's
> >velocity to its own, heading down faster than the original photons.
> >For a smaller distance. This repeats until the many-times-reflected
> >photons have (as far as we can measure) infinite speed.
>
> >  That a problem for you?
>
> No problem.
> That's exactly what would happen....but if you do the sums you will see the
> practical limitations.

Handwaving. What sums, what limitations?

RADAR works as if lightspeed were finite and fixed. If lightspeed
were variable it would work differently.


Mark L. Fergerson
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