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From: Tim Golden BandTech.com on 25 Jun 2010 09:32
Timo Nieminen wrote:
> On Thu, 24 Jun 2010, Tim Golden BandTech.com wrote:
>
>> On Jun 24, 9:52 am, Edward Green <spamspamsp...(a)netzero.com> wrote:
>> > On May 31, 8:57 pm, "Tim BandTech.com" <tttppp...(a)yahoo.com> wrote:
>> >
>> > <...>
>> >
>> > > The most blatant farce is in terms of conservation of energy. The
>> > > claim is that the light hitting a reflective surface will provide
>> > > twice the momentum; one kick when the light hits it and one kick again
>> > > from the light when it leaves. This concept offends the conservation
>> > > of energy. 1300 watts in with 1300 watts out leaves no acceleration
>> > > whatsoever for the perfect reflector.
>> >
>> > It leaves room for a force. If the reflector starts to move away, then
>> > the spectrum will be conveniently downshifted by Doppler. I presume
>> > energy conservation will be mollified.
>>
>> Well, this is a matter of velocity, and we are supposed to get that
>> velocity via a force or an acceleration, so your logic is flawed here.
>> The mirror in stasis needs to provide the acceleration at zero velocity,
>> due to directed electromagnetic radiation, so the Doppler behavior may
>> be a side effect of this process, but is not consistent with causing the
>> flat plate reflector behavior, from the simplest analysis.
>
> Consider an object starting to move from rest. Force F, mass m.
>
> F = ma
>
> v(0) = 0
>
> v(t) = at
>
> p = mv = mat = Ft
>
> KE = 1/2 m v(t)^2 = 1/2 m a^2 t^2
>
> What are the rates of change?
>
> dp/dt = d(Ft)/dt = F (as expected, from Newton 2)
>
> dKE/dt = m a^2 t
>
> At t = 0, when the object is still stationary, the rate of change of KE is
> zero.
>
> We have dKE/dt = m a^2 t = Fv, proportional to the speed. This result, and
> the other results above, don't depend on the nature of the force. It's a
> general result in classical mechanics, that no work is done on a
> stationary object.
>
> Now consider this along with Doppler shift of a beam providing the force
> by reflection. The change in power due to the Doppler shift is
> proportional to velocity,

I am sorry to split out right here, but this is just the point that I've
stated over and over again. At zero velocity the Doppler shift is zero.
I accept the confluence, and that red shifting the light is a means to
extract energy, and so this process as a microturbine could be a
realistic power generation system, though the rate of rotation will have
to be relativistically high, so that atomic or electron processes will
be more relevant than a literal turbine. Still, this turbine model is
fine. If we start the turbine spinning at high speed, shadowed by
another turbine at the vane return side, then a series of these turbines
can be a direct mechanical energy converter, according to the kinetic
interpretation of light that we've been discussing. Still, this
procedure is more analogous to feeding a current at the field coils of a
generator in order to extract electricity from mechanical energy. With
no field coil no electricity will be generated. Got to prime the pump.
The Doppler interpretation is fine for a new solar cell technology, but
not for the radiation pressure study. It is two different situations.
Reliance upon the Doppler argument will likewise conflict with doubling
claims on perfect reflectors. The perfect reflector itself is a broken
construction under the Doppler analysis.

I suppose we should look forward to solar cells that will require a DC
initiation voltage. If this is overlooked in experiments that attempt
new cells then that could be a problem. Such cells could stall out as well.

- Tim

> the rate of doing work (i.e., the power) on the
> reflector is proportional to the velocity. Perfect match.
>
From: Timo Nieminen on 25 Jun 2010 19:04
On Jun 25, 11:32 pm, "Tim Golden BandTech.com" <tttppp...(a)yahoo.com>
wrote:
> Timo Nieminen wrote:
> > On Thu, 24 Jun 2010, Tim Golden BandTech.com wrote:
>
> >> On Jun 24, 9:52 am, Edward Green <spamspamsp...(a)netzero.com> wrote:
> >> > On May 31, 8:57 pm, "Tim BandTech.com" <tttppp...(a)yahoo.com> wrote:
>
> >> > <...>
>
> >> > > The most blatant farce is in terms of conservation of energy. The
> >> > > claim is that the light hitting a reflective surface will provide
> >> > > twice the momentum; one kick when the light hits it and one kick again
> >> > > from the light when it leaves. This concept offends the conservation
> >> > > of energy. 1300 watts in with 1300 watts out leaves no acceleration
> >> > > whatsoever for the perfect reflector.
>
> >> > It leaves room for a force. If the reflector starts to move away, then
> >> > the spectrum will be conveniently downshifted by Doppler. I presume
> >> > energy conservation will be mollified.
>
> >> Well, this is a matter of velocity, and we are supposed to get that
> >> velocity via a force or an acceleration, so your logic is flawed here.
> >> The mirror in stasis needs to provide the acceleration at zero velocity,
> >> due to directed electromagnetic radiation, so the Doppler behavior may
> >> be a side effect of this process, but is not consistent with causing the
> >> flat plate reflector behavior, from the simplest analysis.
>
> > Consider an object starting to move from rest. Force F, mass m.
>
> > F = ma
>
> > v(0) = 0
>
> > v(t) = at
>
> > p = mv = mat = Ft
>
> > KE = 1/2 m v(t)^2 = 1/2 m a^2 t^2
>
> > What are the rates of change?
>
> > dp/dt = d(Ft)/dt = F (as expected, from Newton 2)
>
> > dKE/dt = m a^2 t
>
> > At t = 0, when the object is still stationary, the rate of change of KE is
> > zero.
>
> > We have dKE/dt = m a^2 t = Fv, proportional to the speed. This result, and
> > the other results above, don't depend on the nature of the force. It's a
> > general result in classical mechanics, that no work is done on a
> > stationary object.
>
> > Now consider this along with Doppler shift of a beam providing the force
> > by reflection. The change in power due to the Doppler shift is
> > proportional to velocity,
>
> I am sorry to split out right here, but this is just the point that I've
> stated over and over again. At zero velocity the Doppler shift is zero.
> I accept the confluence, and that red shifting the light is a means to
> extract energy,

.... so what is the problem?

[moved]
> The Doppler interpretation is fine for a new solar cell technology, but
> not for the radiation pressure study. It is two different situations.
> Reliance upon the Doppler argument will likewise conflict with doubling
> claims on perfect reflectors.

No, it's the other way around. It gives a simple explanation for the
force on a perfect reflector, not (by itself) for the force on an
absorber. For an absorber, you have to deal with the absorbed energy.
For a perfect reflector, there is no absorbed energy. For a perfect
reflector, the rate of doing work must equal the loss of power due to
the Doppler. There's no other source of energy, and there is nowhere
else for the "lost" energy to go.

This is the same for elastic collisions of classical particles,
"hosing" a reflector with a stream of classical liquid, and reflection
of a wave.

> The perfect reflector itself is a broken
> construction under the Doppler analysis.

So you keep saying. "Perfect" means "no absorption". Whether or not
you want to use a different definition, you need to keep in mind that
this is what others mean by "perfect reflector". Similarly, "elastic"
collision means no loss of mechanical energy, no heating.

[back to the start]
> I accept the confluence, and that red shifting the light is a means to
> extract energy, and so this process as a microturbine could be a
> realistic power generation system, though the rate of rotation will have
> to be relativistically high, so that atomic or electron processes will
> be more relevant than a literal turbine.

Electromagnetic drive of a turbine? Complete with red-shifting as the
"source" of energy? Sounds like you're getting close to rediscovering
the electric motor. (An electric motor isn't usually analysed this
way, but it's a valid analysis.) The advantage of a turbine is that
you use the change in angular momentum to obtain a torque to do work,
not change in momentum to obtain a force to do work. The classical
paper is R. D'E. Atkinson, "Energy and Angular Momentum in Certain
Optical Problems", Phys. Rev. 47, 623–627 (1935), and you might be
able to find a free copy online.

Two questions for doing this for power generation are: (a) How does
the efficiency in practice compare with photoelectric, photosynthesis,
or photothermal power? (b) Can you extract power from an incident
random field (sounds like a Brownian ratchet problem)?

> I suppose we should look forward to solar cells that will require a DC
> initiation voltage. If this is overlooked in experiments that attempt
> new cells then that could be a problem. Such cells could stall out as well.

The problem isn't efficiency (over 40% has already been done), the
problem is cheap efficiency. There's plenty of sunlight, plenty of
free space, it's a question of cost. Which is why organic solar cells
get so much attention, even though their efficiency is really poor
compared to the more efficienct technologies.

--
Timo
From: Tim Golden BandTech.com on 30 Jun 2010 09:26
Timo Nieminen wrote:
> On Jun 25, 11:32 pm, "Tim Golden BandTech.com" <tttppp...(a)yahoo.com>
> wrote:
>> Timo Nieminen wrote:
>>> On Thu, 24 Jun 2010, Tim Golden BandTech.com wrote:
>>>> On Jun 24, 9:52 am, Edward Green <spamspamsp...(a)netzero.com> wrote:
>>>> > On May 31, 8:57 pm, "Tim BandTech.com" <tttppp...(a)yahoo.com> wrote:
>>>> > <...>
>>>> > > The most blatant farce is in terms of conservation of energy. The
>>>> > > claim is that the light hitting a reflective surface will provide
>>>> > > twice the momentum; one kick when the light hits it and one kick again
>>>> > > from the light when it leaves. This concept offends the conservation
>>>> > > of energy. 1300 watts in with 1300 watts out leaves no acceleration
>>>> > > whatsoever for the perfect reflector.
>>>> > It leaves room for a force. If the reflector starts to move away, then
>>>> > the spectrum will be conveniently downshifted by Doppler. I presume
>>>> > energy conservation will be mollified.
>>>> Well, this is a matter of velocity, and we are supposed to get that
>>>> velocity via a force or an acceleration, so your logic is flawed here.
>>>> The mirror in stasis needs to provide the acceleration at zero velocity,
>>>> due to directed electromagnetic radiation, so the Doppler behavior may
>>>> be a side effect of this process, but is not consistent with causing the
>>>> flat plate reflector behavior, from the simplest analysis.
>>> Consider an object starting to move from rest. Force F, mass m.
>>> F = ma
>>> v(0) = 0
>>> v(t) = at
>>> p = mv = mat = Ft
>>> KE = 1/2 m v(t)^2 = 1/2 m a^2 t^2
>>> What are the rates of change?
>>> dp/dt = d(Ft)/dt = F (as expected, from Newton 2)
>>> dKE/dt = m a^2 t
>>> At t = 0, when the object is still stationary, the rate of change of KE is
>>> zero.
>>> We have dKE/dt = m a^2 t = Fv, proportional to the speed. This result, and
>>> the other results above, don't depend on the nature of the force. It's a
>>> general result in classical mechanics, that no work is done on a
>>> stationary object.
>>> Now consider this along with Doppler shift of a beam providing the force
>>> by reflection. The change in power due to the Doppler shift is
>>> proportional to velocity,
>> I am sorry to split out right here, but this is just the point that I've
>> stated over and over again. At zero velocity the Doppler shift is zero.
>> I accept the confluence, and that red shifting the light is a means to
>> extract energy,
>
> ... so what is the problem?
>
> [moved]
>> The Doppler interpretation is fine for a new solar cell technology, but
>> not for the radiation pressure study. It is two different situations.
>> Reliance upon the Doppler argument will likewise conflict with doubling
>> claims on perfect reflectors.
>
> No, it's the other way around. It gives a simple explanation for the
> force on a perfect reflector, not (by itself) for the force on an
> absorber. For an absorber, you have to deal with the absorbed energy.
> For a perfect reflector, there is no absorbed energy. For a perfect
> reflector, the rate of doing work must equal the loss of power due to
> the Doppler. There's no other source of energy, and there is nowhere
> else for the "lost" energy to go.

But isn't this a chicken and egg type of problem? We cannot claim the
Doppler shift to be the cause of the motion of the vane. Yet you are
attributing the work done to this effect. There is something missing in
this analysis. As I think of a Nichol's vane on a quartz fiber torsion
spring then it is turned into a relativistic problem under this
analysis, yet the doubling required no such analysis. Is this new
physics? If so, then I do not believe it is complete. If anything this
new physics is a foot in the mouth to the old analysis.

>
> This is the same for elastic collisions of classical particles,
> "hosing" a reflector with a stream of classical liquid, and reflection
> of a wave.
>
>> The perfect reflector itself is a broken
>> construction under the Doppler analysis.
>
> So you keep saying. "Perfect" means "no absorption". Whether or not
> you want to use a different definition, you need to keep in mind that
> this is what others mean by "perfect reflector". Similarly, "elastic"
> collision means no loss of mechanical energy, no heating.

Well, maybe this can help to close the loop. If we use a laser source to
keep the math simple and have a reflector traveling at relativistic
speeds (rather than a stationary vane) then we will be discussing an
appreciable transfer of energy.

Let's suppose a Crookes type of device, so that the experiment could be
done on a lab table. Upon getting the vanes to high speed the laser
light, being red shifted substantially, should yield ever more drive to
the device. If we could get a 50% redshift, then we'd be taking 50% of
the laser energy and converting it into mechanical energy, or
acceleration of the vane. Should this work? I suppose to keep the vanes
balanced there should be two laser sources, so that the bearing does not
wear out, but now the bearing friction will be more negligible, since we
are out of the photon momentum realm. We'll have a nifty spectroscopic
effect as we sample the reflected light around the loop, so the dynamics
of the math is worse than I've portrayed, but still, at normal incidence
the simple math will hold. If we want more power we'd put on more vanes
and more lasers, and pulse the lasers for max power at normals.

If the above is believable, then we have isolated this effect away from
the photon momentum haven't we?

>
> [back to the start]
>> I accept the confluence, and that red shifting the light is a means to
>> extract energy, and so this process as a microturbine could be a
>> realistic power generation system, though the rate of rotation will have
>> to be relativistically high, so that atomic or electron processes will
>> be more relevant than a literal turbine.
>
> Electromagnetic drive of a turbine? Complete with red-shifting as the
> "source" of energy? Sounds like you're getting close to rediscovering
> the electric motor. (An electric motor isn't usually analysed this
> way, but it's a valid analysis.) The advantage of a turbine is that
> you use the change in angular momentum to obtain a torque to do work,
> not change in momentum to obtain a force to do work. The classical
> paper is R. D'E. Atkinson, "Energy and Angular Momentum in Certain
> Optical Problems", Phys. Rev. 47, 623�627 (1935), and you might be
> able to find a free copy online.

Couldn't find this article freely.

>
> Two questions for doing this for power generation are: (a) How does
> the efficiency in practice compare with photoelectric, photosynthesis,
> or photothermal power? (b) Can you extract power from an incident
> random field (sounds like a Brownian ratchet problem)?

Here for this argument we should consider that when we computed the
photon momentum it was attributed via
e = h f
which is the entire energy of the photon. This is the only reason that I
can claim this light turbine should work. I agree that the noise type of
problem makes trouble from a signal perspective, yet it appears to be
remedied within the photon momentum interpretation. I don't honestly
know what to believe, but have attempted falsification as a first step.
This is the skeptical approach.

>
>> I suppose we should look forward to solar cells that will require a DC
>> initiation voltage. If this is overlooked in experiments that attempt
>> new cells then that could be a problem. Such cells could stall out as well.
>
> The problem isn't efficiency (over 40% has already been done), the
> problem is cheap efficiency.

Yes, well, the problem here on this thread is the freedom we are taking
in traversing from a mechanical momentum model to an electric model. I
suppose in that electrons can be regarded as springs with ratchets then
this is not so challenging, yet the light itself was electromagnetic,
before the mechanical analogy. I really have to spend more time back at
how energy waves can have momentum, as you've stated earlier.

- Tim

> There's plenty of sunlight, plenty of
> free space, it's a question of cost. Which is why organic solar cells
> get so much attention, even though their efficiency is really poor
> compared to the more efficienct technologies.
>
> --
> Timo
From: NoEinstein on 30 Jun 2010 12:05
On Jun 30, 9:26 am, "Tim Golden BandTech.com" <tttppp...(a)yahoo.com>
wrote:
>
Dear Tim: The "electromagnetic analogy of light" mentioned at the
bottom of your reply was the erroneous theory for explaining how light
could move in the ether. For the most part, photons are jumbles of
polar IOTAs (the smallest energy units in the Universe). The jumbles
have 'poles' in different directions, negating having light be
attracted by magnets, or influenced by... fields. The IOTAs can
orient pole to pole to form chains which encircle the Universe perhaps
'infinite' times. But because the chains are fragile, those tend to
form away from places with very high photon emissions. The Earth's
magnet field gets around this problem by laying claim to certain
designated 'flux line' zones that the light passes around. When solar
flares break the flux lines, there can be power disruptions on Earth
until they can knit back together. Photons travel perfectly well
across the Swiss Cheese voids between the galaxies, which have little
or no ether. Such voids, as for the entire Universe, are bounded by
an electromagnetised meniscus of the polar IOTAs. — NoEinstein —
>
> Timo Nieminen wrote:
> > On Jun 25, 11:32 pm, "Tim Golden BandTech.com" <tttppp...(a)yahoo.com>
> > wrote:
> >> Timo Nieminen wrote:
> >>> On Thu, 24 Jun 2010, Tim Golden BandTech.com wrote:
> >>>> On Jun 24, 9:52 am, Edward Green <spamspamsp...(a)netzero.com> wrote:
> >>>>  > On May 31, 8:57 pm, "Tim BandTech.com" <tttppp...(a)yahoo.com> wrote:
> >>>>  > <...>
> >>>>  > > The most blatant farce is in terms of conservation of energy. The
> >>>>  > > claim is that the light hitting a reflective surface will provide
> >>>>  > > twice the momentum; one kick when the light hits it and one kick again
> >>>>  > > from the light when it leaves. This concept offends the conservation
> >>>>  > > of energy. 1300 watts in with 1300 watts out leaves no acceleration
> >>>>  > > whatsoever for the perfect reflector.
> >>>>  > It leaves room for a force. If the reflector starts to move away, then
> >>>>  > the spectrum will be conveniently downshifted by Doppler. I presume
> >>>>  > energy conservation will be mollified.
> >>>> Well, this is a matter of velocity, and we are supposed to get that
> >>>> velocity via a force or an acceleration, so your logic is flawed here.
> >>>> The mirror in stasis needs to provide the acceleration at zero velocity,
> >>>> due to directed electromagnetic radiation, so the Doppler behavior may
> >>>> be a side effect of this process, but is not consistent with causing the
> >>>> flat plate reflector behavior, from the simplest analysis.
> >>> Consider an object starting to move from rest. Force F, mass m.
> >>> F = ma
> >>> v(0) = 0
> >>> v(t) = at
> >>> p = mv = mat = Ft
> >>> KE = 1/2 m v(t)^2 = 1/2 m a^2 t^2
> >>> What are the rates of change?
> >>> dp/dt = d(Ft)/dt = F (as expected, from Newton 2)
> >>> dKE/dt = m a^2 t
> >>> At t = 0, when the object is still stationary, the rate of change of KE is
> >>> zero.
> >>> We have dKE/dt = m a^2 t = Fv, proportional to the speed. This result, and
> >>> the other results above, don't depend on the nature of the force. It's a
> >>> general result in classical mechanics, that no work is done on a
> >>> stationary object.
> >>> Now consider this along with Doppler shift of a beam providing the force
> >>> by reflection. The change in power due to the Doppler shift is
> >>> proportional to velocity,
> >> I am sorry to split out right here, but this is just the point that I've
> >> stated over and over again. At zero velocity the Doppler shift is zero..
> >> I accept the confluence, and that red shifting the light is a means to
> >> extract energy,
>
> > ... so what is the problem?
>
> > [moved]
> >> The Doppler interpretation is fine for a new solar cell technology, but
> >> not for the radiation pressure study. It is two different situations.
> >> Reliance upon the Doppler argument will likewise conflict with doubling
> >> claims on perfect reflectors.
>
> > No, it's the other way around. It gives a simple explanation for the
> > force on a perfect reflector, not (by itself) for the force on an
> > absorber. For an absorber, you have to deal with the absorbed energy.
> > For a perfect reflector, there is no absorbed energy. For a perfect
> > reflector, the rate of doing work must equal the loss of power due to
> > the Doppler. There's no other source of energy, and there is nowhere
> > else for the "lost" energy to go.
>
> But isn't this a chicken and egg type of problem? We cannot claim the
> Doppler shift to be the cause of the motion of the vane. Yet you are
> attributing the work done to this effect. There is something missing in
> this analysis. As I think of a Nichol's vane on a quartz fiber torsion
> spring then it is turned into a relativistic problem under this
> analysis, yet the doubling required no such analysis. Is this new
> physics? If so, then I do not believe it is complete. If anything this
> new physics is a foot in the mouth to the old analysis.
>
>
>
> > This is the same for elastic collisions of classical particles,
> > "hosing" a reflector with a stream of classical liquid, and reflection
> > of a wave.
>
> >> The perfect reflector itself is a broken
> >> construction under the Doppler analysis.
>
> > So you keep saying. "Perfect" means "no absorption". Whether or not
> > you want to use a different definition, you need to keep in mind that
> > this is what others mean by "perfect reflector". Similarly, "elastic"
> > collision means no loss of mechanical energy, no heating.
>
> Well, maybe this can help to close the loop. If we use a laser source to
> keep the math simple and have a reflector traveling at relativistic
> speeds (rather than a stationary vane) then we will be discussing an
> appreciable transfer of energy.
>
> Let's suppose a Crookes type of device, so that the experiment could be
> done on a lab table. Upon getting the vanes to high speed the laser
> light, being red shifted substantially, should yield ever more drive to
> the device. If we could get a 50% redshift, then we'd be taking 50% of
> the laser energy and converting it into mechanical energy, or
> acceleration of the vane. Should this work? I suppose to keep the vanes
> balanced there should be two laser sources, so that the bearing does not
> wear out, but now the bearing friction will be more negligible, since we
> are out of the photon momentum realm. We'll have a nifty spectroscopic
> effect as we sample the reflected light around the loop, so the dynamics
> of the math is worse than I've portrayed, but still, at normal incidence
> the simple math will hold. If we want more power we'd put on more vanes
> and more lasers, and pulse the lasers for max power at normals.
>
> If the above is believable, then we have isolated this effect away from
> the photon momentum haven't we?
>
>
>
>
>
>
>
> > [back to the start]
> >> I accept the confluence, and that red shifting the light is a means to
> >> extract energy, and so this process as a microturbine could be a
> >> realistic power generation system, though the rate of rotation will have
> >> to be relativistically high, so that atomic or electron processes will
> >> be more relevant than a literal turbine.
>
> > Electromagnetic drive of a turbine? Complete with red-shifting as the
> > "source" of energy? Sounds like you're getting close to rediscovering
> > the electric motor. (An electric motor isn't usually analysed this
> > way, but it's a valid analysis.) The advantage of a turbine is that
> > you use the change in angular momentum to obtain a torque to do work,
> > not change in momentum to obtain a force to do work. The classical
> > paper is R. D'E. Atkinson, "Energy and Angular Momentum in Certain
> > Optical Problems", Phys. Rev. 47, 623–627 (1935), and you might be
> > able to find a free copy online.
>
> Couldn't find this article freely.
>
>
>
> > Two questions for doing this for power generation are: (a) How does
> > the efficiency in practice compare with photoelectric, photosynthesis,
> > or photothermal power? (b) Can you extract power from an incident
> > random field (sounds like a Brownian ratchet problem)?
>
> Here for this argument we should consider that when we computed the
> photon momentum it was attributed via
>     e = h f
> which is the entire energy of the photon. This is the only reason that I
> can claim this light turbine should work. I agree that the noise type of
> problem makes trouble from a signal perspective, yet it appears to be
> remedied within the photon momentum interpretation. I don't honestly
> know what to believe, but have attempted falsification as a first step.
> This is the skeptical approach.
>
>
>
> >> I suppose we should look forward to solar cells that will require a DC
> >> initiation voltage. If this is overlooked in experiments that attempt
> >> new cells then that could be a problem. Such cells could stall out as well.
>
> > The problem isn't efficiency (over 40% has already been done), the
> > problem is cheap efficiency.
>
> Yes, well, the problem here on this thread is the freedom we are taking
> in traversing from a mechanical momentum model to an electric model. I
> suppose in that electrons can be regarded as springs with ratchets then
> this is not so challenging, yet the light itself was electromagnetic,
> before the mechanical analogy. I really have to spend more time back at
> how energy waves can have momentum, as you've stated earlier.
>
>   - Tim
>
>  > There's plenty of sunlight, plenty of
>
>
>
> > free space, it's a question of cost. Which is why organic solar cells
> > get so much attention, even though their efficiency is really poor
> > compared to the more efficienct technologies.
>
> > --
> > Timo- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

From: Timo Nieminen on 1 Jul 2010 00:17
On Jun 30, 11:26 pm, "Tim Golden BandTech.com" <tttppp...(a)yahoo.com>
wrote:
> Timo Nieminen wrote:
> > No, it's the other way around. It gives a simple explanation for the
> > force on a perfect reflector, not (by itself) for the force on an
> > absorber. For an absorber, you have to deal with the absorbed energy.
> > For a perfect reflector, there is no absorbed energy. For a perfect
> > reflector, the rate of doing work must equal the loss of power due to
> > the Doppler. There's no other source of energy, and there is nowhere
> > else for the "lost" energy to go.
>
> But isn't this a chicken and egg type of problem? We cannot claim the
> Doppler shift to be the cause of the motion of the vane. Yet you are
> attributing the work done to this effect. There is something missing in
> this analysis.

The "cause" of the work is exactly what is missing here.

Consider a classical ball bouncing off a reflector. KE_in - KE_out -
energy lost if collision is not elastic tells you the work done, but
doesn't tell you how the work is done. For that, you might model the
ball as an elastic body, described by some value of Young's modulus or
bulk modulus. Perhaps that isn't much of an explanation, so you could
consider the interaction between the atoms that hold the ball
together, and the interaction between the ball atoms and the reflector
atoms that stop interpenetration. There's a lot of detail you can go
into in order to explain the force. The energy analysis only tells you
the work done, not the details of how the work is done.

For an EM wave, the Lorentz force will give you the details. What kind
of reflector? For a perfect conductor, start with a non-perfect
conductor, and find the fields and currents in the material. Find the
Lorentz force density on the medium. Find the time average. Take the
limit as conductivity -> infinity. Done! Same numerical result as from
the energy analysis, and explanation of the details, at the cost of a
lot more effort. Not happy with the simple model of the medium where
we describe it electromagnetically by permittivity and conductivity?
Fancier models are available (e.g., see Drude model of conductivity).
Make it more complicated, and stop where desired.

> As I think of a Nichol's vane on a quartz fiber torsion
> spring then it is turned into a relativistic problem under this
> analysis, yet the doubling required no such analysis. Is this new
> physics? If so, then I do not believe it is complete. If anything this
> new physics is a foot in the mouth to the old analysis.

No new physics, just conservation of energy and momentum.
Relativistic? In a sense, but works fine with Galileian relativity, as
long as the reflector moves slowly compared to the speed of light.

> Let's suppose a Crookes type of device, so that the experiment could be
> done on a lab table. Upon getting the vanes to high speed the laser
> light, being red shifted substantially, should yield ever more drive to
> the device. If we could get a 50% redshift, then we'd be taking 50% of
> the laser energy and converting it into mechanical energy, or
> acceleration of the vane. Should this work?

Why shouldn't it work? But be careful with language! You write "more
drive", but note well that this means "more power", not "more force".
With the device as described, you'd get _less_ force as it spins
faster (but still more power). Why less force? Unlike the previous
analysis of the redshift/blueshift, which was done with a chnage of
coordinate system, you're talking about a real motion of the vane
relative to the source, so a redshift seen by the vane, so a reduction
in power as seen by the vane.

> If the above is believable, then we have isolated this effect away from
> the photon momentum haven't we?

"Isolated away from" means what? Photon energy and momentum (or the
classical equivalent) and conservation of energy and momentum still
describe it.

--
Timo
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