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#1380 by TheTraveller on 09 Sep, 2017 17:31
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To be VERY CLEAR. A non accelerating cavity, relative to the trapped photons, WILL NOT GENERATE ANY FORCE NOR WILL IT INITIATE ACCELERATION.
How can an object accelerate "relative to the trapped photons"? Acceleration only makes sense relative to a certain reference frame. You cannot associate a reference frame with a photon because it always propagates with the same speed in ANY reference frame.
Hi Wicoe,
Acceleration of the cavity, relative to the trapped photons, generates red Doppler shifted photons at the small end and blue Doppler shifted photons at the big end. -
#1381 by TheTraveller on 09 Sep, 2017 17:34
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That complicates things and I doubt that. Otherwise you would need some auxiliary device to get it started in space.
Hi Bob,
It is correct. An external force is needed to move the cavity from Idle Mode to Motor Mode. Clearly explained in Roger's various papers.
In a non accelerating cavity there are no Doppler shifted photons and without Doppler shifted photons there is no force generated, no acceleration and no self sustaining Doppler shifted photons. -
#1382 by RonM on 09 Sep, 2017 17:37
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When that technique is applied in space, interesting things happen as a new inertial rest frame is created between each short burst of acceleration. That rest frame can then be used to measure velocity and KE increase during the next short burst of acceleration.
To be VERY CLEAR. A non accelerating cavity, relative to the trapped photons, WILL NOT GENERATE ANY FORCE NOR WILL IT INITIATE ACCELERATION.
That complicates things and I doubt that. Otherwise you would need some auxiliary device to get it started in space.
Good point, Bob012345. If the EM drive is accelerating in short bursts and it does not initiate acceleration by itself, what is creating the initial acceleration to get each burst started? -
#1383 by wicoe on 09 Sep, 2017 17:39
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Acceleration of the cavity, relative to the trapped photons, generates red Doppler shifted photons at the small end and blue Doppler shifted photons at the big end.
Thanks! So you need a constant external force to be applied to the EmDrive to cause acceleration and generate the doppler shift difference? And of course, the EmDrive will exert an equal but opposite reaction force onto the source of that force... or is it going to "help" the external force and act in the same direction, thus amplifying it? -
#1384 by TheTraveller on 09 Sep, 2017 17:40
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When that technique is applied in space, interesting things happen as a new inertial rest frame is created between each short burst of acceleration. That rest frame can then be used to measure velocity and KE increase during the next short burst of acceleration.
To be VERY CLEAR. A non accelerating cavity, relative to the trapped photons, WILL NOT GENERATE ANY FORCE NOR WILL IT INITIATE ACCELERATION.
That complicates things and I doubt that. Otherwise you would need some auxiliary device to get it started in space.
Good point, Bob012345. If the EM drive is accelerating in short bursts and it does not initiate acceleration by itself, what is creating the initial acceleration to get each burst started?
Hi Ron,
Vibration by various ships systems will provide the necessary very short external acceleration force.
Or maybe fit a mechanical vibrator to the big end plate?
The necessity of the acceleration force is very real. -
#1385 by Bob012345 on 09 Sep, 2017 17:41
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When that technique is applied in space, interesting things happen as a new inertial rest frame is created between each short burst of acceleration. That rest frame can then be used to measure velocity and KE increase during the next short burst of acceleration.
To be VERY CLEAR. A non accelerating cavity, relative to the trapped photons, WILL NOT GENERATE ANY FORCE NOR WILL IT INITIATE ACCELERATION.
That complicates things and I doubt that. Otherwise you would need some auxiliary device to get it started in space.
Good point, Bob012345. If the EM drive is accelerating in short bursts and it does not initiate acceleration by itself, what is creating the initial acceleration to get each burst started?
If it works I think it works without such complications. I think that's just a function of the Shawyer theory which I'm not endorsing. -
#1386 by Bob012345 on 09 Sep, 2017 17:42
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When that technique is applied in space, interesting things happen as a new inertial rest frame is created between each short burst of acceleration. That rest frame can then be used to measure velocity and KE increase during the next short burst of acceleration.
To be VERY CLEAR. A non accelerating cavity, relative to the trapped photons, WILL NOT GENERATE ANY FORCE NOR WILL IT INITIATE ACCELERATION.
That complicates things and I doubt that. Otherwise you would need some auxiliary device to get it started in space.
Good point, Bob012345. If the EM drive is accelerating in short bursts and it does not initiate acceleration by itself, what is creating the initial acceleration to get each burst started?
Hi Ron,
Vibration by various ships systems will provide the necessary very short external acceleration force.
Or maybe fit a mechanical vibrator to the big end plate?
The necessity of the acceleration force is very real.
Basically, you are turning this into a Mach effect thruster! Maybe that's just how it works anyway. -
#1387 by TheTraveller on 09 Sep, 2017 17:43
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Acceleration of the cavity, relative to the trapped photons, generates red Doppler shifted photons at the small end and blue Doppler shifted photons at the big end.
Thanks! So you need a constant external force to be applied to the EmDrive to cause acceleration and generate the doppler shift difference? And of course, the EmDrive will exert an equal but opposite reaction force onto the source of that force... or is it going to "help" the external force and act in the same direction, thus amplifying it?
Hi Wicoe,
Only need a very short time period external force to initiate acceleration. After internal Doppler shifts start, the cavity generates it's own force to support further acceleration. -
#1388 by TheTraveller on 09 Sep, 2017 17:46
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When that technique is applied in space, interesting things happen as a new inertial rest frame is created between each short burst of acceleration. That rest frame can then be used to measure velocity and KE increase during the next short burst of acceleration.
To be VERY CLEAR. A non accelerating cavity, relative to the trapped photons, WILL NOT GENERATE ANY FORCE NOR WILL IT INITIATE ACCELERATION.
That complicates things and I doubt that. Otherwise you would need some auxiliary device to get it started in space.
Good point, Bob012345. If the EM drive is accelerating in short bursts and it does not initiate acceleration by itself, what is creating the initial acceleration to get each burst started?
If it works I think it works without such complications. I think that's just a function of the Shawyer theory which I'm not endorsing.
Hi Bob,
Without an initial short external force that causes initial acceleration, how will initial cavity Doppler shifts occur? -
#1389 by meberbs on 09 Sep, 2017 17:49
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So you continue to ignore Special Relativity, which makes it very clear the photons and cavity have seperate frames, thus are an open system and allow photon momentum and energy to be transferred to cavity mass while obeying CofM and CofE via lost photon momentum and energy?
It is apparently difficult for you to understand. What do you think "open system" means?
This is not difficult to understand.
Special relativity has nothing to do with what has a "separate frame." Me and a basketball I had tossed are moving at different speeds, so you could say that we have different rest frames. This has nothing to do with special relativity. It also has nothing to do with whether the system of me+baskeball is open or closed. (hint, it depends on if I am pushing on anything else)
P.S. Others are doing a good job pointing out the complete lack of evidence provided by you, but I want to note that you "being under NDA" doesn't make sense. If anything it is the company buying from you that should be under NDA, with maybe restrictions on you identifying them, although even that wouldn't be typical.
You can't equate the way light works to basketballs in simple classical reference frames. So TT is partly correct.
Hi Bob,
What happens to the photons trapped inside the cavity is explained by microwave physics and the Compton Effect that defines each time a photon impacts an orbital electron of a metallic atom both CofE and CofM are in effect.
Roger has stated many times that if the cavity is not accelerating relative to the trapped photons, NO FORCE IS GENERATED. Roger has also stated that the cavity needs an external force to be applied to initiale small end forward acceleration.
So the question should be: Why does acceleration produce an asymmetric force that supports self sustained acceleration?
To be VERY CLEAR. A non accelerating cavity, relative to the trapped photons, WILL NOT GENERATE ANY FORCE NOR WILL IT INITIATE ACCELERATION.
TT, Why don't you answer my question from before before going off on another tangent: What do you think "open system" means?
Or if that is too hard for you try these:
What is the total momentum of a cavity at rest before you turn it on?
What is the total momentum of the cavity after it has accelerated some amount and then been turned off (lets say a 10 kg cavity and 5m/s velocity)?
After the cavity is off, is there anything else in the universe that has different momentum than before the drive was turned on? -
#1390 by TheTraveller on 09 Sep, 2017 17:55
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Giys,
To support the need for an initial accelerative force to trigger EmDrive self generated accelerative force, here is what Roger states.
Please review page 3, section 4 of this document:
http://www.emdrive.com/EmDriveForceMeasurement.pdf
where Roger states:Quote4. Practical static measurement techniques
A number of methods have been used in the UK, the US and China to measure the forces produced by an EmDrive thruster.
In each successful case, the EmDrive force data has been superimposed on an increasing or decreasing background force, generated by the test equipment itself.
Indeed, in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured. -
#1391 by TheTraveller on 09 Sep, 2017 18:06
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TT, Why don't you answer my question from before before going off on another tangent: What do you think "open system" means?
Or if that is too hard for you try these:
What is the total momentum of a cavity at rest before you turn it on?
What is the total momentum of the cavity after it has accelerated some amount and then been turned off (lets say a 10 kg cavity and 5m/s velocity)?
After the cavity is off, is there anything else in the universe that has different momentum than before the drive was turned on?
Meberbs,
Please refer to the image I posted earlier about the subject of open systems. To me it is self explanatory.
As to referencing momentum to distant bodies, as far as I understand it, that is an unproven theory. It really surprises me why you would try to use a unproven theory in our discussions?
Especially as doing a multiple number of short busts of acceleration, creating constant velocity interial rest frames between, is totally with-in existing physics.
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#1392 by wicoe on 09 Sep, 2017 18:11
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Please refer to the image I posted earlier about the subject of open systems. To me it is self explanatory.
Sorry, it does not look self-explanatory to me.. would you care to elaborate? Using words, not images.As to referencing momentum to distant bodies, as far as I understand it, that is an unproven theory. It really surprises me why you would try to use a unproven theory in our discussions?
Especially as doing a multiple number of short busts of acceleration, creating constant velocity interial rest frames between, is totally with-in existing physics.
Why do you keep referring to ref frames as "being created"? They are abstract concepts, they are not created nor destroyed. Regardless of the way you apply power to the "EmDrive", those reference frames can be "created" in your mind, by simply thinking about them and doing calculations. -
#1393 by meberbs on 09 Sep, 2017 18:18
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That image does not include a definition of the phrase "open system." it does however indicate that the person who made it does not know what "open system" means. So again, can you define this phrase, or do you have no idea what you are talking about?TT, Why don't you answer my question from before before going off on another tangent: What do you think "open system" means?
Or if that is too hard for you try these:
What is the total momentum of a cavity at rest before you turn it on?
What is the total momentum of the cavity after it has accelerated some amount and then been turned off (lets say a 10 kg cavity and 5m/s velocity)?
After the cavity is off, is there anything else in the universe that has different momentum than before the drive was turned on?
Meberbs,
Please refer to the image I posted earlier about the subject of open systems. To me it is self explanatory.As to referencing momentum to distant bodies, as far as I understand it, that is an unproven theory. It really surprises me why you would try to use a unproven theory in our discussions?
What in the world are you talking about? I asked you trivial questions, about high school level Newtonian physics.Especially as doing a multiple number of short busts of acceleration, creating constant velocity interial rest frames between, is totally with-in existing physics.
As wicoe stated previously, this sentence in nonsensical. The phrase "creating a rest frame" does not have any meaning in the same way that "Colorless green ideas sleep furiously" is grammatically correct, but nonsensical. -
#1394 by Rodal on 09 Sep, 2017 18:27
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It is natural to conjecture whether the Chinese EM Drive is a deception or a real program (https://en.wikipedia.org/wiki/Military_deception).
However, if it is deception, it is an elaborate one (as shown by the more complicated electromagnetic fields in https://forum.nasaspaceflight.com/index.php?topic=42978.msg1721229#msg1721229 ), and more importantly it is being played (for now) on the CCP and related funding sources, not directly on the West.
It does not appear to be a project that emanated from or interacted with Prof. Yang's research. It appears completely independent: very different designs, and different beginnings.
The Chinese sources did not even bother to put English captions on the video, so it cannot be claimed that they are playing this directly to the West. At most it is indirect.
I guess that Reagan's Star Wars could be mentioned by skeptics as a recent program that the news (New York Times) claimed to involve deliberate deception on the Soviets (see for example: http://www.nytimes.com/1993/08/18/us/lies-and-rigged-star-wars-test-fooled-the-kremlin-and-congress.html?mcubz=0)QuoteOfficials in the "Star Wars" project rigged a crucial 1984 test and faked other data in a program of deception that misled Congress as well as the intended target, the Soviet Union, four former Reagan Administration officials said.
The deception program was designed to feed the Kremlin half-truths and lies about the project, the former Administration officials said. It helped persuade the Soviets to spend tens of billions of dollars to counter the American effort to develop a space-based shield against nuclear attack proposed by former President Ronald Reagan in 1983, they said.
One big difference with Star Wars, is that it is relatively very cheap to do this EM Drive R&D (in comparison with the Star Wars project), so even as a deception, it does not make much sense because it would not divert much defense money to seriously investigate the EM Drive in the West. There are much better ways to produce deception than by a program that a number of people are currently investigating in their own homes... You could not do a Do-It-Yourself with Star Wars. Getting the Soviets to spend a lot of money in their Buran -with the thought that it could be used to deploy large payloads in LEO needing cosmonauts or needing repair- servicing- diverted a huge amount of money (15 billion rubles). The cost of these EM Drives is nothing by comparison. In FY 2015, Pentagon and related spending totaled $598 billion.
Also the Chinese satellite being shown on Chinese TV produces 30,000 watts, so they have a good amount of power, 30 kW to play with, apparently!
My conclusion is that it is much more probable that this is not a deception. That the Chinese saw the EM Drive as a lottery ticket, as an out-of-the-money option: an R&D project that is very cheap to investigate and that has an unlikely big payoff. If the likely (*) outcome takes place that it does not work in space, then they lost very little in money. If it does work, then they reap a huge payoff for a very small amount of money.
(*) Why likely? due to the lack of an accepted theoretical explanation as to why it should work -
#1395 by TheTraveller on 09 Sep, 2017 18:35
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Please refer to the image I posted earlier about the subject of open systems. To me it is self explanatory.
Sorry, it does not look self-explanatory to me.. would you care to elaborate? Using words, not images.As to referencing momentum to distant bodies, as far as I understand it, that is an unproven theory. It really surprises me why you would try to use a unproven theory in our discussions?
Especially as doing a multiple number of short busts of acceleration, creating constant velocity interial rest frames between, is totally with-in existing physics.
Why do you keep referring to ref frames as "being created"? They are abstract concepts, they are not created nor destroyed. Regardless of the way you apply power to the "EmDrive", those reference frames can be "created" in your mind, by simply thinking about them and doing calculations.
Hi Wicoe,
Totally agree that ALL constant velocity inertial reference frames are abstract concepts, yet we use them to measure real velocity relative to two of these abstract frames
None of the above invalidates using the last rest frame before acceleration starts to measure the change in velocity vs the rest frame after acceleration has finished.
As to Roger's open system, what i believe he is saying is the trapped photons can transfer momentum and KE to the cavity without the photons velocity altering.
He also states that an observer on the cavity interior surface will not observe any alteration in the photon velocity as cavity velocity alters. Last time I looked that was what Einstein said when defining special relativity.
The trick of course is to be able to generate an asymmetric force inside the cavity that supports continual cavity acceleration.
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#1396 by TheTraveller on 09 Sep, 2017 18:43
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That image does not include a definition of the phrase "open system." it does however indicate that the person who made it does not know what "open system" means. So again, can you define this phrase, or do you have no idea what you are talking about?TT, Why don't you answer my question from before before going off on another tangent: What do you think "open system" means?
Or if that is too hard for you try these:
What is the total momentum of a cavity at rest before you turn it on?
What is the total momentum of the cavity after it has accelerated some amount and then been turned off (lets say a 10 kg cavity and 5m/s velocity)?
After the cavity is off, is there anything else in the universe that has different momentum than before the drive was turned on?
Meberbs,
Please refer to the image I posted earlier about the subject of open systems. To me it is self explanatory.As to referencing momentum to distant bodies, as far as I understand it, that is an unproven theory. It really surprises me why you would try to use a unproven theory in our discussions?
What in the world are you talking about? I asked you trivial questions, about high school level Newtonian physics.Especially as doing a multiple number of short busts of acceleration, creating constant velocity interial rest frames between, is totally with-in existing physics.
As wicoe stated previously, this sentence in nonsensical. The phrase "creating a rest frame" does not have any meaning in the same way that "Colorless green ideas sleep furiously" is grammatically correct, but nonsensical.
Meberbs,
To calc momentum we need to know mass and velocity. To know velocity we need another inertial reference frame.
Simple to then use the inertial frame of our mass pre acceleration vs the post acceleration inertial reference frame to calc gained momentum.
As for Open Systems this works for me:
https://en.m.wikipedia.org/wiki/Open_and_closed_systems_in_social_scienceQuoteLudwig Bertalanffy describes two types of systems:
open systems and closed systems.
The open systems are systems that allow interactions between their internal elements and the environment.
An open system is defined as a “system in exchange of matter with its environment, presenting import and export, building-up and breaking-down of its material components.”[1]
Closed systems, on the other hand, are held to be isolated from their environment.
Equilibrium thermodynamics, for example, is a field of study that applies to closed systems.
The sun will be rising shortly and I need sleep. Nite, nite. -
#1397 by Rodal on 09 Sep, 2017 19:06
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...
As for Open Systems this works for me:
https://en.m.wikipedia.org/wiki/Open_and_closed_systems_in_social_science
...
A definition of open and closed systems from Social Sciences works for you, to explain the EM Drive's motion according to Shawyer?Quote from: WikipediaSocial science is a major category of academic disciplines, concerned with society and the relationships among individuals within a society. It in turn has many branches, each of which is considered a "social science". The social sciences include economics, political science, human geography, demography, psychology, sociology, anthropology, archaeology, jurisprudence, history, and linguistics.
https://en.m.wikipedia.org/wiki/Social_science
Using a definition from Social Sciences because the EM Drive is perceived by you as a Social Science phenomenon rather than a Natural Science phenomenon? Does Shawyer agree with that?
For the thermodynamics definition of open and closed systems see: https://en.wikipedia.org/wiki/Closed_system#In_thermodynamics
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#1398 by wicoe on 09 Sep, 2017 19:11
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The open systems are systems that allow interactions between their internal elements and the environment.
If the EmDrive is an "open system", can you please describe what kind of interactions occur between the elements of the EmDrive and the environment? -
#1399 by meberbs on 09 Sep, 2017 19:18
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To calc momentum we need to know mass and velocity. To know velocity we need another inertial reference frame.
I gave you both mass and velocity. In giving you velocity I was giving you a defined inertial frame to do the calculations in. Yet, you did not answer the questions.Simple to then use the inertial frame of our mass pre acceleration vs the post acceleration inertial reference frame to calc gained momentum.
Just do the calculations in one frame. Conservation of momentum is defined for a single frame, meaning you don't switch frames mid calculation.As for Open Systems this works for me:
Since you did not provide a definition in your own words and quoted significantly more from the article than the one line that defines an open system, it seems that you still don't actually understand what an open system is.
https://en.m.wikipedia.org/wiki/Open_and_closed_systems_in_social_science