Author Topic: EM Drive Developments - related to space flight applications - Thread 10  (Read 552600 times)

Online tchernik

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Paul, Michelle:

Just to mention that I find the Galilean do-the-experiment approach to science you follow most commendable and aligned with a sort of Renaissance spirit.

The world would be a very different place, if more people regarded truth and empiricism so highly as you do.

I have a lot of respect for good scientists in general, but to spend significant personal resources in the quest of finding the truth in a topic many don't believe is worth the effort, requires something else in terms of personal commitment and courage.

People like you are an example to others, and the reason why we should keep some faith in the human race, no matter what we see and live around ourselves.

Offline ThatOtherGuy

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So, Paul now you have quite a number of ideas and ... although I'd leave ASGARD to shells (due to height) it"s up to you ... and we'll probably have more ideas (e.g. EPOS ;D)

Offline Stormbringer

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I always considered magnetic and electrical "waves" to be distortions in the space-time continuum, much like gravity, not as something physical that moves through space.  Clearly it is a different sort of distortion, but the ways in which electrical and magnetic fields interact with solid objects are not entirely different from the way gravitation interacts with mass.  Somewhere in there lurks the Unified Field theory.

What if spacetime was quantized? Imagine spacetime not as a continuum but as a multidimensional map of successive discrete "tiny squares" each described by an unknown "quantum entity" (don't know how to call such thing surely equal or below the Planck length). Then an electromagnetic wave would be the physical interpretation of a step by step propagation through one "case" to the next one, of the "activation" and "deactivation" of such a quantum entity through spacetime. As for the associated particle (a photon, but why not also any particle composing matter) would be the physical local interpretation of an "activated case" (or the average of a group of activated cases, if one wants to include Heisenberg's uncertainty principle in that very rough idea).

Following that idea, nothing really "propagates" physically, only the information, which triggers the apparent movement of the wave and of its associated particle. A moving particle would then be like those light arrays on top of a wall in the dark, sequentially switched on and off rapidly with a little delay with respect to the previous one, giving the impression of a luminous object quickly propagating through space, whereas in fact there is only an apparent propagation and no movement at all… :P

Another way to express such a view: considering the atomic orbital of an electron in an atom. With the appropriate amount of energy, an electron can "jump" from an orbital to the other. This is a quantum leap, a discrete atomic electron transition. The wave function changes. But fundamentally, is it really the same electron which jumped from one orbital to the other, or is the higher energy electron a different one than the previous one described on a lower energy orbital…

There are fundamental differences between gravitation and electromagnetism, even considering the field theory without any quantization.

One very interesting thing about gravitation is that in 4 spacetime (3 D space + time) (*) one can have a zero stress-energy tensor, and still have non-zero energy and momentum in the gravitational field.



This follows immediately from the fact that zero right hand side of the gravitational field equation (zero stress-energy tensor), means zero left hand side (zero Einstein's tensor). But zero Einstein tensor in 4 spacetime does not necessarily mean a flat spacetime. The equality is between the Einstein tensor and the stress-energy tensor.  Zero Einstein tensor does not equal a flat spacetime geometry.  The Einstein tensor is not equal to the Ricci tensor.  The Einstein tensor is equal to the difference between the Ricci tensor and the scalar curvature (times the metric tensor). 






Both can add up to zero, and yet have non-zero components.  One can have zero stress-energy tensor in 4 spacetime and still have non-zero energy and momentum in the gravitational field !  One can have gravitational wave disturbances with zero source: zero stress-energy density tensor. 

This is very different from electromagnetism where the electromagnetic fields (photons) do not carry any charge. In a gravitational field one can have a zero energy density, and still have gravitational waves. Thus we have self-interaction in gravitation due to the nonlinearity of the gravitational equations.  A gravitational wave with a small energy relative to the curvature will travel along a null geodesic in the curved spacetime geometry. This is a different path than it would travel in the absence of the spacetime curvature. Thus one can have self-interaction: the gravitational field interacting with itself.

This issue involves energy conservation and self-interaction in 4D spacetime, something that many posters discussing "overunity" really struggle with.  In General Relativity you can have energy and momentum on the left hand side of the equation, unlike charges in electromagnetism (electromagnetic waves in vacuum or in space without charges do not carry any charge: photons have no charge).

(*) This is only possible in 4 spacetime (3 D space + time) and higher.  In 3 spacetime (2 D space + time) a zero stress-energy tensor necessarily implies a zero curvature of spacetime and hence in 3 spacetime (2 D space + time)  the gravitational field would not be able to carry energy and momentum.  In 4 spacetime electromagnetism, the electromagnetic fields (photons) do not carry any charge.

Have you read this:  http://www.preposterousuniverse.com/blog/2013/10/03/guest-post-lance-dixon-on-calculating-amplitudes/

for N=8 a graviton's feynman diagram is the same as a double copy of a gluon valid to the fifth loop order and counting.

Quote
Along the way, Zvi, John Joseph and Henrik, thanks to the time-honored method of “just staring at” the loop integrand provided by unitarity, also stumbled on a new property of gauge theory amplitudes, which tightly couples them to gravity. They found that gauge theory amplitudes can be written in such a way that their kinematic part obeys relations that are structurally identical to the Jacobi identities known to fans of Lie algebras. This so-called color-kinematics duality, when achieved, leads to a simple “double copy” prescription for computing amplitudes in suitable theories of gravity: Take the gauge theory amplitude, remove the color factors and square the kinematic numerator factors. Crudely, a graviton looks very much like two gluons laid on top of each other. If you’ve ever looked at the Feynman rules for gravity, you’d be shocked that such a simple prescription could ever work, but it does. Although these relations could in principle have been discovered without unitarity-based methods, the power of the methods to provide very simple expressions, led people to find initial patterns, and then easily test the patterns in many other examples to gain confidence.

Not for nothing but there is a certain fringe kook (with the initials B.( or R. ) L. )who has claimed for decades that gravity and the strong force are the same force operating at different scales in relation to UFO conspiracy stuff.

He might be a kook but the folks mentioned in the article most certainly aren't kooks. Because:

Quote
This year’s Sakurai Prize of the American Physical Society, one of the most prestigious awards in theoretical particle physics, has been awarded to Zvi Bern, Lance Dixon, and David Kosower “for pathbreaking contributions to the calculation of perturbative scattering amplitudes, which led to a deeper understanding of quantum field theory and to powerful new tools for computing QCD processes.”
When antigravity is outlawed only outlaws will have antigravity.

Offline Star-Drive

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Paul, Michelle:

Just to mention that I find the Galilean do-the-experiment approach to science you follow most commendable and aligned with a sort of Renaissance spirit.

The world would be a very different place, if more people regarded truth and empiricism so highly as you do.

I have a lot of respect for good scientists in general, but to spend significant personal resources in the quest of finding the truth in a topic many don't believe is worth the effort, requires something else in terms of personal commitment and courage.

People like you are an example to others, and the reason why we should keep some faith in the human race, no matter what we see and live around ourselves.

All: "Apprentice Sorcerer Gravity Appliances Reaction Devices (ASGARD) works for me!  :)  I just hope Thor doesn't mind...

tchernik:

"...and the reason why we should keep some faith in the human race, no matter what we see and live around ourselves."

Please remember that the past and present news media around the world continue to push the "if it bleeds, it leads" headlines to sell "their" copy and their editor's and publishers political agenda on all sides.  What gets lost in the daily news grind is the fact that most humans are good, law abiding folks that just want to make a living and get along with their family, friends and neighbors, with as little fuss as possible.  So take heart that we will find a collective way to make our civilization work and work well for most of us, as we navigate our way into the future.

Ad Astra my friends!  Paul M.
« Last Edit: 05/23/2017 06:51 PM by Star-Drive »
Star-Drive

Offline Star-Drive

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All:

I ran across a paper on the unification of GRT and QM this morning that IMO we all need to consider in regards to what is real and what is mathematics devoid of physical content.

Best, Paul M.
Star-Drive

Online RotoSequence

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All:

I ran across a paper on the unification of GRT and QM this morning that IMO we all need to consider in regards to what is real and what is mathematics devoid of physical content.

Best, Paul M.

I gave it a skim... the ratio of essay to data and math doesn't bode well.  ;D
« Last Edit: 05/23/2017 07:07 PM by RotoSequence »

Offline Stormbringer

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More delicious stuff:

https://phys.org/news/2017-05-blackbody-spacetime-geometry-topology.html

Synopsis:  Gravity like force in blackbody radiation related to topology.
When antigravity is outlawed only outlaws will have antigravity.

Online Monomorphic

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I haven't had much to share lately as I recently returned from vacation.   :-[  I am heading to Cashiers, NC this weekend so I don't expect much to happen until after I get back. 

I am reworking the main power leads yet again. I noticed that any twisted pairs running in the same direction as the piano wire that suspends the torsional pendulum seem to induce more displacement noise. This necessitated moving the pre-amp back to its original location.

Seeing Paul and Shell's new lab lights made me realize just how poor my lighting was. Since I have a dropped ceiling with insulating tiles I was able to find these flush mounted 2'x2' LED light tiles that were very simple to install. So no more poor lighting.  ;D

Offline ThereIWas3

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All labs need a comfy chair, for all the waiting while things stabilize.  :)
« Last Edit: 05/23/2017 09:34 PM by ThereIWas3 »
"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Offline Bob Woods

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All: "Apprentice Sorcerer Gravity Appliances Reaction Devices (ASGARD) works for me!  :)  I just hope Thor doesn't mind...

Boy, be busy and you miss the fun. What about "Paul's Texas Quantum Bar and Boson BBQ"

Offline spupeng7

(...)
I'm thinking about calling either the Gravity Reaction Lab or The Sorcerer's Apprentice Lab.
(...)
The problem with magical references is that they undermine credibility, which is not really what we need right now!
I received a well deserved slap on the wrist when I described Shawyer as having pulled a rabbit out of his hat. I vote for 'Gravity Reaction Lab'   :)
« Last Edit: 05/24/2017 01:45 AM by spupeng7 »
Optimism equals opportunity.

Offline Rodal

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...

There are fundamental differences between gravitation and electromagnetism, even considering the field theory without any quantization.

One very interesting thing about gravitation is that in 4 spacetime (3 D space + time) (*) one can have a zero stress-energy tensor, and still have non-zero energy and momentum in the gravitational field.



This follows  from the fact that zero right hand side of the gravitational field equation (zero stress-energy tensor), means zero left hand side (zero Einstein's tensor). But zero Einstein tensor in 4 spacetime does not necessarily mean a flat spacetime. The equality is between the Einstein tensor and the stress-energy tensor.  Zero Einstein tensor does not equal a flat spacetime geometry.  The Einstein tensor is equal to the difference between the Ricci tensor and the scalar curvature (times the metric tensor). 



Both can add up to zero, and yet have non-zero components.  ADDED IN EDIT: In 4 dimensions the Ricci tensor can be zero and yet the space be curved: non-flat.  Since Ricci tensor equal zero does not necessarily mean flat spacetime, therefore one can have zero stress-energy tensor in 4 spacetime and still have non-zero energy and momentum in the gravitational field !  One can have gravitational wave disturbances with zero source: zero stress-energy density tensor. 

This is very different from electromagnetism where the electromagnetic fields (photons) do not carry any charge. In a gravitational field one can have a zero energy density, and still have gravitational waves. Thus we have self-interaction in gravitation due to the nonlinearity of the gravitational equations.  A gravitational wave with a small energy relative to the curvature will travel along a null geodesic in the curved spacetime geometry. This is a different path than it would travel in the absence of the spacetime curvature. Thus one can have self-interaction: the gravitational field interacting with itself.

This issue involves energy conservation and self-interaction in 4D spacetime, something that many posters discussing "overunity" really struggle with.  In General Relativity you can have energy and momentum on the left hand side of the equation, unlike charges in electromagnetism (electromagnetic waves in vacuum or in space without charges do not carry any charge: photons have no charge).

(*) This is only possible in 4 spacetime (3 D space + time) and higher.  In 3 spacetime (2 D space + time) a zero stress-energy tensor necessarily implies a zero curvature of spacetime (because in 3 dimensions or less zero Ricci tensor means flatness) and hence in 3 spacetime (2 D space + time)  the gravitational field would not be able to carry energy and momentum.  In 4 spacetime electromagnetism, the electromagnetic fields (photons) do not carry any charge.   

ADDED IN EDIT:
The issue has to do with the number of components of the tensor that specifies curvature of space: the number of independent components of the Riemann curvature tensor.  The Riemann curvature tensor has 4 indices:

But the curvature tensor that appears in Einstein's equation is not the Riemann curvature tensor, but is instead the Ricci tensor which has only two indices:



 In 3 D the Ricci tensor has 6 independent components, exactly the same number of independent components as the Riemann curvature tensor has in 3 D: also 6.
 
Therefore, in 3 D, vanishing of the Ricci tensor implies also vanishing of the Riemann curvature.  In 3 D, vanishing of the stress-energy tensor implies vanishing of the Ricci tensor, and vanishing of the Ricci tensor implies vanishing of the Riemann curvature.  Hence in 3 D vanishing of the stress-energy tensor implies a flat geometry.
 
However in 4 D, the Ricci tensor has 10 independent components and the Riemann curvature tensor has 20 independent components.  For 4 dimensions or greater, there will be fewer components of the Ricci tensor than components of the Riemann tensor.
 
Hence for 4 dimensions or greater, the Ricci tensor can vanish, and yet the Riemann curvature tensor may not vanish. Therefore for 4 dimensions or greater vanishing of the stress-energy tensor does not imply flatness of spacetime.

Example: in 4 D spacetime gravitational plane waves have zero Ricci curvature tensor but non-zero Riemannian curvature.  In the region of the gravitational wave disturbance spacetime is not flat, even though the RIcci tensor is zero.
 
The energy and momentum of these gravitational plane waves is not in the energy-stress tensor, but the energy and momentum are in the gravitational field itself. 
 
The stress-energy tensor represents the energy due to matter, but stress-energy tensor includes NO contribution from gravitational energy or momentum in the field itself.
 
When a binary pulsar emits gravitational waves, these waves will carry away energy away and therefore its orbital period should change.  The energy and momentum are in the gravitational wave itself.
 
Thus, in general relativity you can have energy and momentum in gravitational waves, on the left hand side of the equation, on the field itself.  And these wave can interact nonlinearly. 

All very interesting from an energy conservation point of view :-)

Offline JonathanD

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I haven't had much to share lately as I recently returned from vacation.   :-[  I am heading to Cashiers, NC this weekend so I don't expect much to happen until after I get back. 

I am reworking the main power leads yet again. I noticed that any twisted pairs running in the same direction as the piano wire that suspends the torsional pendulum seem to induce more displacement noise. This necessitated moving the pre-amp back to its original location.

Seeing Paul and Shell's new lab lights made me realize just how poor my lighting was. Since I have a dropped ceiling with insulating tiles I was able to find these flush mounted 2'x2' LED light tiles that were very simple to install. So no more poor lighting.  ;D

I appreciate the strategic positioning of the fire extinguisher!

Offline 1

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I haven't had much to share lately as I recently returned from vacation.   :-[  I am heading to Cashiers, NC this weekend so I don't expect much to happen until after I get back. 

I am reworking the main power leads yet again. I noticed that any twisted pairs running in the same direction as the piano wire that suspends the torsional pendulum seem to induce more displacement noise. This necessitated moving the pre-amp back to its original location.

Seeing Paul and Shell's new lab lights made me realize just how poor my lighting was. Since I have a dropped ceiling with insulating tiles I was able to find these flush mounted 2'x2' LED light tiles that were very simple to install. So no more poor lighting.  ;D

I appreciate the strategic positioning of the fire extinguisher!

And that rug really ties the room together.

Offline tleach

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All: "Apprentice Sorcerer Gravity Appliances Reaction Devices (ASGARD) works for me!  :)  I just hope Thor doesn't mind...


Nope, don't mind in the slightest!
T. Thor Leach

Offline ThatOtherGuy

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All: "Apprentice Sorcerer Gravity Appliances Reaction Devices (ASGARD) works for me!  :)  I just hope Thor doesn't mind...

Boy, be busy and you miss the fun. What about "Paul's Texas Quantum Bar and Boson BBQ"

I think that the "Boson BBQ" may be more appropriate for Shells since, apparently, she likes roasting antennas  ;D ;D

Offline ThatOtherGuy

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Probably OT but eyeballing it, the document seems interesting so ... here we go

http://iopscience.iop.org/article/10.1209/0295-5075/117/60001


Offline SeeShells

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Paul, Michelle:

Just to mention that I find the Galilean do-the-experiment approach to science you follow most commendable and aligned with a sort of Renaissance spirit.

The world would be a very different place, if more people regarded truth and empiricism so highly as you do.

I have a lot of respect for good scientists in general, but to spend significant personal resources in the quest of finding the truth in a topic many don't believe is worth the effort, requires something else in terms of personal commitment and courage.

People like you are an example to others, and the reason why we should keep some faith in the human race, no matter what we see and live around ourselves.

All: "Apprentice Sorcerer Gravity Appliances Reaction Devices (ASGARD) works for me!  :)  I just hope Thor doesn't mind...

tchernik:

"...and the reason why we should keep some faith in the human race, no matter what we see and live around ourselves."

Please remember that the past and present news media around the world continue to push the "if it bleeds, it leads" headlines to sell "their" copy and their editor's and publishers political agenda on all sides.  What gets lost in the daily news grind is the fact that most humans are good, law abiding folks that just want to make a living and get along with their family, friends and neighbors, with as little fuss as possible.  So take heart that we will find a collective way to make our civilization work and work well for most of us, as we navigate our way into the future.

Ad Astra my friends!  Paul M.
I've started calling my lab  "High Frontier Labs"

Shell

Offline ThatOtherGuy

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Shell, please don't take offense, I was just kidding !

Offline SeeShells

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Shell, please don't take offense, I was just kidding !
I was calling my lab this for quite some time... no offense. OK?
Hugs,
Shell

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