-
#760 by meberbs on 09 Aug, 2017 19:22
-
Conventional rockets aren't constant force/power. If you look at them in a fixed reference frame (which you must for energy conservation to mean anything) the energy expelled in the exhaust varies, because the faster the rocket is going, the more the change in kinetic energy in the exhaust.I know this has already been discussed over and over and over… but still:
The Machian explanation prevents over-unity globally, at the universe scale. But not necessarily locally. If you're investing a few kWe with a small power source to let the immense flow of almost unlimited potential energy of the universe express in accelerating such a "gravinertial transistor", how can you say the final kinetic energy of the vehicle cannot be harnessed to generate more energy than what has been consumed by the little electrical power source?
Barring an additional unknown mechanism, one probably can't actually say that it avoids local over-unity.
That's exactly my point. If the engine offers constant acceleration under constant power, it is an over-unity device. If not, local CoE may still apply. But I am half-convinced by Shawyer's explanation about Doppler shifts preventing large accelerations, which are more a technological constraint than a fundamental law.
As professor Woodward pointed out, any classical system that provides constant acceleration at a constant power does the same thing. Even conventional rockets. The reason we don't see such effects is because first, most of the energy is lost as reaction mass which is far more than the quadratic gain in the rocket and we explain it by saying the rocket 'borrows' kinetic energy from the reaction mass, and second, it simply runs out of mass first before it gets to that point.
Also, it is probably better to look at the full energy balance, including energy expelled from the rocket in the mass of the exhaust (E=mc^2). This would show from any perspective that the instantaneous Force/Power is less than a photon rocket. Special relativity shows that there is no energy conservation problem at less than a photon rocket force/power ratio.
There therefore is no classical system that does the same thing. -
#761 by flux_capacitor on 09 Aug, 2017 19:58
-
For the launch vehicle...
Force = 1.54 * 8 = 12320 N
acceleration = 12320 / 701 kg = 17.57 m /2
distance traveled from rest in 1 second is .5 * 17.57 = 8.79 m
work = F * d = 12320 * 8.79 = 77862
power = 77862 / 1 second = 78 kw
12.32 kw in, 78 kw out???
Is that right??
Probably. By Mach Theory, the excess energy is coming from the kinetic energy of orbital momentum, preserving CoE and preventing over-unity.
I know this has already been discussed over and over and over… but still:
The Machian explanation prevents over-unity globally, at the universe scale. But not necessarily locally. If you're investing a few kWe with a small power source to let the immense flow of almost unlimited potential energy of the universe express in accelerating such a "gravinertial transistor", how can you say the final kinetic energy of the vehicle cannot be harnessed to generate more energy than what has been consumed by the little electrical power source?
It all comes down as to how one defines energy extraction. Under any definition however, one can use gravitation to extract momentum (as for example in a gravity assist). If per your definition you think that presently one can extract energy from gravitation (for example using a hydoelectric powerplant, due to the momentum of the falling water stored in the reservoir thanks to the thermal cycle coming from the Sun), then yes you would be extracting energy using such a scheme. The momentum and the "energy" coming from the extremely small movement of the other celestial masses (10^55 grams of mass in the Universe). However, if one defines energy extraction thermodynamically as per a closed cycle, then the answer would be no.
I agree
I don't understand what a "gravinertial transistor" means. Gravity and inertia are tied together in General Relativity through the Equivalence Principle https://en.wikipedia.org/wiki/Equivalence_principle , so why write "gravinertial". Are you implying any circumstance under which inertial mass and gravitational mass are not equivalent? I know of lots of experimental tests confirming the equivalence principle and no experimental test showing a difference between inertial and gravitational mass.
Also why "transistor" ? What transistor ? https://en.wikipedia.org/wiki/TransistorQuoteA transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit.
http://www.dictionary.com/browse/transistor
Sorry, I referred to another thread without noticing.
Please see this very recent post from Star-Drive in the Woodward effect thread, and my answer.
The explanation for the name "transistor" (by opposition to a "transducer") is explained in theses posts.
"Gravinertial" is a somewhat kinky word made by combining the two terms "gravity" and "inertia" together, to convey the idea that the source of the inertia of all bodies, as well as the energy borrowed from the universe used to generate thrust in a hypothetical propellantless thruster, according to Mach's principle, comes from gravity (i.e. gravity origin of inertia) but not from gravitational waves themselves, as they are limited to c. Yet inertial reaction forces are instantaneous, hence the need for an "action-at-a-distance" instantaneous radiative field to convey the inertial interaction between a local mass and the distant matter in the rest of the universe, with the help, according to Sciama and Woodward, of the Wheeler-Feynman absorber theory applied to gravitation (with its "retarded" and "advanced" waves).
"Inertial" alone would be misleading as it would not convey the idea of a gravitational interaction with a distant source.
"gravity" alone would also be misleading in this context, as one would certainly think of the gravitational interaction in Mach effects to be due the gravitational field, which is not the case: gravitational waves do not propagate instantaneously. There is an additional ingredient needed (absorber theory). -
#762 by chongma on 09 Aug, 2017 20:28
-
http://emdrives.com stopped working
-
#763 by Rodal on 10 Aug, 2017 00:37
-
...Yet inertial reaction forces are instantaneous, hence the need for an "action-at-a-distance" instantaneous radiative field to convey the inertial interaction between a local mass and the distant matter in the rest of the universe, with the help, according to Sciama and Woodward, of the Wheeler-Feynman absorber theory applied to gravitation (with its "retarded" and "advanced" waves).
Sciama did not write about action at a distance, or about retarded and advanced waves or about absorber theory applied to gravitation.
"Inertial" alone would be misleading as it would not convey the idea of a gravitational interaction with a distant source.
"gravity" alone would also be misleading in this context, as one would certainly think of the gravitational interaction in Mach effects to be due the gravitational field, which is not the case: gravitational waves do not propagate instantaneously. There is an additional ingredient needed (absorber theory).
Sciama's PhD thesis was a simple theory with a vector potential, as an analogy to electromagnetism, based on the Machian idea that inertia and gravitation are entirely determined by the distribution of matter. In the published version (1953 https://academic.oup.com/mnras/article/113/1/34/2602000/On-the-Origin-of-Inertia), Sciama promised to develop a relativistic theory with a tensor potential (as in Einstein’s theory) in a second paper.
The second paper did not appear until 16 years later, in 1969, and it was very different from his original intention. Sciama Waylen and Gilman, instead gave an integral formulation of Einstein’s theory rather than developing an alternative Machian theory: https://journals.aps.org/pr/abstract/10.1103/PhysRev.187.1762
Furthermore, Sciama et.al. confined their discussion to a normal neighborhood of the field point. It was a later student of Sciama,(Derek Raine in 1975 http://bit.ly/2vGDGmV ), who showed how to handle this limit and investigated what types of manifold did not violate Mach's principle (essentially you must have isotropy). Barbour took a completely different approach later on. Neither Sciama, nor Raine, nor Barbour used absorber theory.
It seems to me that you are confusing Sciama with Hoyle and Narlikar, who are the ones that developed a theory of gravitation based on advanced and retarded waves in 1964 http://ayuba.fr/mach_effect/hoyle-narlikar1964.pdf, which is 5 years before Sciama wrote his second paper, in 1969, where Sciama gave an integral formulation of Einstein’s theory rather than developing an alternative Machian theory. Notice that Raine does not even mention Hoyle and Narlikar in Raine's paper (even though their theory had been around for more than a decade at that time).
I still don't like the word "gravinertial":
*when we use language we use words that have a commonly accepted meaning and this word does not have a commonly accepted meaning
*all cosmological measurements performed so far strongly verify the Equivalence principle, that gravitational mass and gravitational inertia are identical. Just gravitation should be enough.
Einstein was influenced by Mach. It seems to me that all we need is Einstein and Einstein is all we need, as far as gravitation and inertia are concerned. Gravity Probe B verified this. Gravity Probe B did not find anything that was not adequately explained by Einstein's theory. http://news.stanford.edu/news/2011/may/gravity-probe-mission-050411.html
-
#764 by ThinkerX on 10 Aug, 2017 00:40
-
Quote
One thought I've had to explain the SSC magnet and EMdrive examples has been a topological "knot" with planetary/solar/both magnetic fields that briefly couples to the resonance mode in the cavity - that's the "lurch".
The CoE is with a loss of angular momentum of the larger system.
The transient scale is with the flux density of the interaction cross section.
The transient duration determined by the combined system stability as a "momentum dump".
The end to end effect on momentum is to access gravity held momentum, as with a so called "sling shot" maneuver.
Suggestions on how the DIY types here could test for this? -
#765 by spupeng7 on 10 Aug, 2017 03:20
-
OK Bob,http://emdrive.com/ is worth a look today :-)
Thanks for the link. But let's wait until real details and data is provided before we fire up the barbie.
Plans for 3G Demonstrator developing...
can I propose a Big BBQ for all members of this forum to celebrate verifiable levitation when it actually is verified. I will be happy to attend your yard if that suits you. I'd be happy to attend this event just about anywhere... I'll even bring my own beer (as is the Aussie custom)
-
#766 by Chrochne on 10 Aug, 2017 04:59
-
http://emdrives.com stopped working
You have wrong address.
It is http://emdrive.com/ and not with (s) -
#767 by Bob Woods on 10 Aug, 2017 05:53
-
I would love to host a BBQ for the folks on this forum! I grew up mostly in Texas and make mesquite smoked ribs and meat. Since I moved to the Pacific Northwest I have also made Alder smoked salmon. And as far as beer, Oregon isn't known as "Beervanna" for nothing!
OK Bob,http://emdrive.com/ is worth a look today :-)
Thanks for the link. But let's wait until real details and data is provided before we fire up the barbie.
Plans for 3G Demonstrator developing...
can I propose a Big BBQ for all members of this forum to celebrate verifiable levitation when it actually is verified. I will be happy to attend your yard if that suits you. I'd be happy to attend this event just about anywhere... I'll even bring my own beer (as is the Aussie custom) 
-
#768 by flux_capacitor on 10 Aug, 2017 10:26
-
Sciama did not write about action at a distance, or about retarded and advanced waves or about absorber theory applied to gravitation.
Sciama's PhD thesis was a simple theory with a vector potential, as an analogy to electromagnetism, based on the Machian idea that inertia and gravitation are entirely determined by the distribution of matter. In the published version (1953 https://academic.oup.com/mnras/article/113/1/34/2602000/On-the-Origin-of-Inertia), Sciama promised to develop a relativistic theory with a tensor potential (as in Einstein’s theory) in a second paper.
I disagree. In his 1964 paper, which is a reformulation of his previous vector theory of gravity in a tensor formalism equivalent to general relativity:
• Sciama, D.W. (1964). "The Physical Structure of General Relativity". Reviews of Modern Physics. 36 (1): 463–469.
he wrote a passage about Mach's principle and the need for an action at a distance field, possibly the same kind than the Wheeler-Feynman absorber theory:Quote from: Dennis Sciama2. MACH'S PRINCIPLE
There are many ways of stating Mach's principle: we shall adopt the form "inertial forces are exerted by matter, not by absolute space." In this form the principle contains two ideas:
(i) Inertial forces have a dynamical rather than a kinematical origin, and so must be derived from a field theory, or possibly an action-at-a-distance theory in the sense of J.A. Wheeler and R.P. Feynman [Rev. Mod. Phys. 21, 425 (1949)]
(ii) The whole of the inertial field must be due to sources, so that in solving the inertial field equations the boundary conditions must be chosen appropriately.
We consider these two ideas in turn.
He was the first to call for such an instantaneous radiative field applied to gravity, long before Woodward, who correctly credits Sciama for this idea in his book MSAS (Springer 2013).It seems to me that you are confusing Sciama with Hoyle and Narlikar, who are the ones that developed a theory of gravitation based on advanced and retarded waves in 1964 http://ayuba.fr/mach_effect/hoyle-narlikar1964.pdf, which is 5 years before Sciama wrote his second paper, in 1969, where Sciama gave an integral formulation of Einstein’s theory rather than developing an alternative Machian theory. Notice that Raine does not even mention Hoyle and Narlikar in Raine's paper (even though their theory had been around for more than a decade at that time).
I'm not. I know that Dennis Sciama did not develop a Machian theory a gravity himself, but was the first to evoke the requirement for an instantaneous action at a distance field, Wheeler-Feynman absorber type, to develop such a Machian theory.
I know that Fred Hoyle and Jayant Narlikar developed their Machian theory of gravity, i.e. fully integrating Mach's principe, whereas Einstein's general relativity did not (Einstein was really influenced by Ernst Mach, up to be convinced that the "strong" version of Mach's principle is real, but he didn't find a way to blend it as a formalism in his theory of general relativity).
I also know that Hoyle and Narlikar were mainly motivated for modeling a steady state universe, with a continuous creation of matter out of "nothing" at the center of quasars, using creation fields (or C-field). But when this peculiar C-field is removed from the theory, thus when the Hoyle-Narlikar theory is no longer steady state, it can be developed as a Machian theory of relativity describing an accelerating expanding universe, like Heidi Fearn does with her Gravitational Absorber Theory (a term you even coined).
Fearn's Gravitational Absorber Theory, or Hoyle-Narlikar theory without C-field, reduces to Einstein's general relativity in the limit of a smooth fluid model of particle distribution and a transformation of coordinates into the rest frame of the fluid to simplify the field equations. It becomes equivalent to general relativity, with Mach's principle included.I still don't like the word "gravinertial":
*when we use language we use words that have a commonly accepted meaning and this word does not have a commonly accepted meaning
*all cosmological measurements performed so far strongly verify the Equivalence principle, that gravitational mass and gravitational inertia are identical. Just gravitation should be enough.
Einstein was influenced by Mach. It seems to me that all we need is Einstein and Einstein is all we need, as far as gravitation and inertia are concerned. Gravity Probe B verified this. Gravity Probe B did not find anything that was not adequately explained by Einstein's theory. http://news.stanford.edu/news/2011/may/gravity-probe-mission-050411.html
Einstein was influenced by Mach and wanted to include Mach's principle within his theory of general relativity, but he eventually did not, especially because there is no instantaneous inertial mechanism involving a retarded/advanced radiative field in general relativity.
If Einstein's general relativity included Mach's principle, that's all we would need indeed. But it is not the case, and Einstein himself was affected by such a miss. As Abraham Pais, quoting Einstein, wrote in his book Subtle is the Lord: the Science and the Life of Albert Einstein (Oxford University Press, 2005), pp. 287–288:QuoteSo strongly did Einstein believe at that time in the relativity of inertia that in 1918 he stated as being on an equal footing three principles on which a satisfactory theory of gravitation should rest:
1. The principle of relativity as expressed by general covariance.
2. The principle of equivalence.
3. Mach's principle (the first time this term entered the literature): … that the gµν are completely determined by the mass of bodies, more generally by Tµν.
In 1922, Einstein noted that others were satisfied to proceed without this [third] criterion and added, "This contentedness will appear incomprehensible to a later generation however."
As I said, gravitational waves have a limited propagation rate, the speed of light. That's why Heidi Fearn had to resort to an non-steady state version of H-N theory, which includes retarded and advanced waves that explain instantaneous inertial reaction forces, in order to build a theory including Mach's principle that allows Mach effects and its developments related to space flight applications.
Languages evolve. Maybe "gravinertial" is not the right term. But someday, if Fearn's theory proves to be correct and explains genuine Mach effects, we'll have to find a word summarizing the idea of an instantaneous radiative field with retarded and advanced waves, making all gravitational sources of the universe interact and explaining the inertia of bodies. -
#769 by Rodal on 10 Aug, 2017 12:17
-
In your frantic effort to try to make your point you are not accurately quoting Sciama, as the passage ["or possibly an action-at-a-distance theory in the sense of J.A. Wheeler and R.P. Feynman"] was only mentioned in a footnote in his 1964 paper !Sciama did not write about action at a distance, or about retarded and advanced waves or about absorber theory applied to gravitation.
Sciama's PhD thesis was a simple theory with a vector potential, as an analogy to electromagnetism, based on the Machian idea that inertia and gravitation are entirely determined by the distribution of matter. In the published version (1953 https://academic.oup.com/mnras/article/113/1/34/2602000/On-the-Origin-of-Inertia), Sciama promised to develop a relativistic theory with a tensor potential (as in Einstein’s theory) in a second paper.
I disagree. In his 1964 paper, which is a reformulation of his previous vector theory of gravity in a tensor formalism equivalent to general relativity:
• Sciama, D.W. (1964). "The Physical Structure of General Relativity". Reviews of Modern Physics. 36 (1): 463–469.
he wrote a passage about Mach's principle and the need for an action at a distance field, possibly the same kind than the Wheeler-Feynman absorber theory:Quote from: Dennis Sciama2. MACH'S PRINCIPLE
There are many ways of stating Mach's principle: we shall adopt the form "inertial forces are exerted by matter, not by absolute space." In this form the principle contains two ideas:
(i) Inertial forces have a dynamical rather than a kinematical origin, and so must be derived from a field theory, or possibly an action-at-a-distance theory in the sense of J.A. Wheeler and R.P. Feynman [Rev. Mod. Phys. 21, 425 (1949)]
(ii) The whole of the inertial field must be due to sources, so that in solving the inertial field equations the boundary conditions must be chosen appropriately.
We consider these two ideas in turn.
He was the first to call for such an instantaneous radiative field applied to gravity, long before Woodward, who correctly credits Sciama for this idea in his book MSAS (Springer 2013)....
I doubt that anyone else reading Sciama's 1964 paper would claim that Sciama was the first to use advanced-retarded waves and absorber theory when Sciama only mentions it in a footnote (and Sciama never developed a Gravitational absorber theory, as in the 1964 paper besides that single context to "consider the analogous problem in electrodynamics" he does not develop a gravitational theory with advanced-retarded waves) while simultaneously, in the same university (Cambridge) Narlikar was pursuing his PhD thesis with Hoyle for years developing a full gravitational absorber theory that culminated in 4 full papers in the same year 1964. And the fact that Sciama never mentioned advanced-retarded waves or absorber theory before this footnote or afterwards.
Mentioning in a footnote the possibility of creating a Gravitational Absorber Theory is not the same thing as actually doing it. Hoyle and Narlikar were doing it for years at the same university (which may readily explain Sciama's footnote, as the work of Hoyle and Narlikar was not secret, as it is understandable that Sciama heard about their work: Sciama, Hoyle and Narlikar were all at Cambridge University).
As to Sciama's later views on this subject (besides the 1969 paper I previously quoted) watch the conversation in 1986 between Abdus Salam (1979 Nobel Prize for electroweak unification), Dennis Sciama, Edward Witten (35 years old at the time, known for string theory and quantum gravity work at the Institute of Advanced Studies in Princeton)and Paolo Budinich talking about physics.
Notice (towards the end of the conversation, starting at @44:00) in 1951 Sciama made a switch from Statistical Mechanics towards General Relativity, at a time that Cambridge had few people that taught General Relativity.At a time that Sciama said: none of the revolution of modern astrophysics had occurred at the time. Sciama came up with his Mach theory paper at a time when Sciama admits that practically nothing of what we know today about the cosmos (black holes, neutron stars, etc.) had been observed. When asked by Salam what was Sciama's Ph.D. thesis about, Sciama answers, rather reluctantly,"something to do with Mach's principle" "which Sciama says he had already worked out before Dirac was made his official thesis adviser, so Dirac did not have anything to do with it", he emphasizes that his "Mach principle" work had nothing to do with the torsion stuff that Salam knew Sciama for, either. Sciama refers to his graduate work as "before the modern era" of astrophysical observations. Sciama says that was after he had already formed his "Mach principle" graduate work that the revolution of observational astronomy, starting with radio astronomy in 1952,came about. Sciama remembers when neutron stars (not just black holes) at the time of his graduate work were considered to be "not respectable work."
We are in the year 2017. By now all measurements show that inertial mass is identical to gravitational mass.
Gravity Probe B has verified Einstein's theory and there is no cosmological measurements that have revealed any Machian effect not already present in Einstein's theory.
You state that advanced/retarded waves are necessary to explain inertia. Sciama himself (besides the single footnote from 1964, where he only mentions it as a possibility) did not mention again the need for advanced/retarded waves to explain gravitation and inertia.
The Universe has a structure, due to gravity and inertia: planetary systems, galaxies, clusters, super-clusters, which is explained by Einstein's theory of gravitation. The revolution in cosmological measurements, has fully confirmed Einstein's theory concerning the equivalence between gravitational mass and inertial mass: they are identical. -
#770 by flux_capacitor on 10 Aug, 2017 12:46
-
Thank you for the video.
I wrote nothing but the same thing you said, but in a more compact manner. The quote about the Wheeler-Feynman absorber theory is indeed located in Sciama's 1964 paper, as everyone can read since I directly pointed to the full PDF paper. I linked to that paper because you said in a previous post that he never mentioned anything like that in this paper or any other one, and I proved he did. The fact that he wrote that in a footnote does not change the situation. I don't feel that pulling a note up to the text body of a short quote in a web forum constitutes a misquote, especially as I provided the link to the paper, enough to get to the root, in a willingness of truth.
I didn't say neither that Sciama developed that kind of theory himself, I even precised in my previous message: "I know that Dennis Sciama did not develop such a Machian theory a gravity himself, but was the first to evoke the requirement for an instantaneous action at a distance field, Wheeler-Feynman absorber type, to develop such a Machian theory."
I don't understand your point about opposing the fact that Sciama simply evoked the need for an absorber theory applied to gravity as soon as 1964 in a paper, against the fact that he didn't develop a gravitational absorber theory himself, two different things that I think I clearly differentiated in my post.
If some things need to be made clearer, here is a short summarization of the two ideas I wrote:
- Has Sciama developed a theory of gravity implying a gravitational absorber radiative field after Wheeler & Feynman? No.
- Has Sciama evoked the fact that a working Machian theory of gravity could be modeled using such an instantaneous "action-at-a-distance" field similar to the Wheeler-Feynman absorber theory in a footnote of his 1964 paper? Yes.
I don't think there is much more to say about this. -
#771 by Rodal on 10 Aug, 2017 12:53
-
Thank you for the video....I don't think there is much more to say about this.
Thank you for the conversation on this topic and for bringing up the 1964 paper by Sciama. As you said, regarding historical attribution people can make their own minds.
Regarding gravitation and inertia, and Machian effects, Gravity Probe B [http://news.stanford.edu/news/2011/may/gravity-probe-mission-050411.html] shows that Einstein's General Relativity is all one needs.
Also, all the measurements so far of gravitational waves fully confirm Einstein's theory of gravity during the plunging and coalescence of binary black holes.
Is the book closed on the subject? There is some room for small deviations (Gravity Probe B measurements did not meet the precision initially sought). One of the foremost experts on the subject of experimental measurements of General Relativity, Clifford Will, wrote: "Even though it is popular lore that Einstein was right (I even wrote a book on the subject), no such book is ever completely closed in science. " https://physics.aps.org/articles/v4/43
-
#772 by Rodal on 10 Aug, 2017 15:22
-
http://emdrives.com stopped working
You have wrong address.
It is http://emdrive.com/ and not with (s)
Two different addresses:
http://emdrive.com/ is the address used by SPR (Shawyer)
http://emdrives.com was an address that was created by someone at the time that interest in the EM Drive was at a peak (during threads 2 and 3, at the time following the 2014 initial disclosure that NASA Eagleworks was working on this, the time at which White was even talking to the press about Q drives and even interstellar travel based on the Alcubierre drive, and about tabletop experiments with interferometers https://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field_interferometer). Then http://emdrives.com used to link automatically to these threads at NSF.
It is not clear to me what the purpose of http://emdrives.com ever was, but apparently this domain name expired on 8/3/2017 and is pending renewal or deletion. -
#773 by flux_capacitor on 10 Aug, 2017 15:42
-
It is not clear to me what the purpose of http://emdrives.com ever was, but apparently this domain name expired on 8/3/2017 and is pending renewal or deletion.
If I remember correctly, http://emdrives.com was always pointing to the last page of the current NSF thread about the EmDrive. I didn't use it personally, but it was a convenient way to follow the (quickly expanding) debate here. -
#774 by TheTraveller on 10 Aug, 2017 15:54
-
This link will take you to the newest post on the current EmDrive thread:
https://forum.nasaspaceflight.com/index.php?topic=42978.new;topicseen#new
Ditto for the current Woodward thread:
https://forum.nasaspaceflight.com/index.php?topic=31037.new;topicseen#new -
#775 by Bob012345 on 10 Aug, 2017 17:56
-
Conventional rockets aren't constant force/power. If you look at them in a fixed reference frame (which you must for energy conservation to mean anything) the energy expelled in the exhaust varies, because the faster the rocket is going, the more the change in kinetic energy in the exhaust.I know this has already been discussed over and over and over… but still:
The Machian explanation prevents over-unity globally, at the universe scale. But not necessarily locally. If you're investing a few kWe with a small power source to let the immense flow of almost unlimited potential energy of the universe express in accelerating such a "gravinertial transistor", how can you say the final kinetic energy of the vehicle cannot be harnessed to generate more energy than what has been consumed by the little electrical power source?
Barring an additional unknown mechanism, one probably can't actually say that it avoids local over-unity.
That's exactly my point. If the engine offers constant acceleration under constant power, it is an over-unity device. If not, local CoE may still apply. But I am half-convinced by Shawyer's explanation about Doppler shifts preventing large accelerations, which are more a technological constraint than a fundamental law.
As professor Woodward pointed out, any classical system that provides constant acceleration at a constant power does the same thing. Even conventional rockets. The reason we don't see such effects is because first, most of the energy is lost as reaction mass which is far more than the quadratic gain in the rocket and we explain it by saying the rocket 'borrows' kinetic energy from the reaction mass, and second, it simply runs out of mass first before it gets to that point.
Also, it is probably better to look at the full energy balance, including energy expelled from the rocket in the mass of the exhaust (E=mc^2). This would show from any perspective that the instantaneous Force/Power is less than a photon rocket. Special relativity shows that there is no energy conservation problem at less than a photon rocket force/power ratio.
There therefore is no classical system that does the same thing.
Were not going to agree here so let's not go through infinite loops debating it. But I hope you can agree that no matter the increased kinetic energy in the exhaust, the chemical energy released (rocket power) can be uniform from the perspective of the rocket. I'm suggesting that's what matters. Everything else is perspective dependent. We wouldn't say an accelerating EMDrive or MEGA drive has to use increased electrical power because it's going faster. We shouldn't say that for a rocket as well.
-
#776 by bmcgaffey20 on 10 Aug, 2017 19:02
-
OKAY --- *blows whistle*
Let me ask the big couple of questions nobody else has asked yet.
When and where can I buy one, and how much will it cost?
No, seriously though there is a surprisingly low amount of skepticism right now for such ground breaking claims. Is it now really happening? -
#777 by RotoSequence on 10 Aug, 2017 19:11
-
OKAY --- *blows whistle*
Let me ask the big couple of questions nobody else has asked yet.
When and where can I buy one, and how much will it cost?
No, seriously though there is a surprisingly low amount of skepticism right now for such ground breaking claims. Is it now really happening?
The skepticism is definitely in place, it's just well worn territory by now after ten threads. The latest grandiose claims of thrust are mostly background noise against test data, the theoretical physics, and third party replication efforts. -
#778 by Elrond Cupboard on 10 Aug, 2017 19:35
-
I'd love to be proven wrong, but until I see some concrete demonstration of the latest claims I'm afraid I'm going to be of the opinion that R Shawyer is a raving fantasist.OKAY --- *blows whistle*
Let me ask the big couple of questions nobody else has asked yet.
When and where can I buy one, and how much will it cost?
No, seriously though there is a surprisingly low amount of skepticism right now for such ground breaking claims. Is it now really happening?
The skepticism is definitely in place, it's just well worn territory by now after ten threads. The latest grandiose claims of thrust are mostly background noise against test data, the theoretical physics, and third party replication efforts. -
#779 by Star One on 10 Aug, 2017 20:13
-
I'd love to be proven wrong, but until I see some concrete demonstration of the latest claims I'm afraid I'm going to be of the opinion that R Shawyer is a raving fantasist.OKAY --- *blows whistle*
Let me ask the big couple of questions nobody else has asked yet.
When and where can I buy one, and how much will it cost?
No, seriously though there is a surprisingly low amount of skepticism right now for such ground breaking claims. Is it now really happening?
The skepticism is definitely in place, it's just well worn territory by now after ten threads. The latest grandiose claims of thrust are mostly background noise against test data, the theoretical physics, and third party replication efforts.
I wish people would stop repeating time and again the error of speaking as if Shawyer is the only show in town. There are a number of dedicated experimentalists and theorists working in this area, by repeatedly ignoring them you are doing them a disservice.
