One question, regarding Mr. Shawyer's understanding of what's going on in his EM-drive:Let's pretend we are a photon. We are traveling at c. Due to Lorentz-contraction of space in our traveling direction, how does the universe look like for us, a photon? I think that the universe actually appears as a sort of surface in our traveling direction, due to the maximum Lorentz contraction of space in front of us.The question is: For a photon, moving at c, how does the inner geometry of an EM-drive frustum really look like? Could there be an apparent nonlinearity, from the viewpoint of a photon, within an EM-drive device, that we in our everyday, non-Lorentz contracted world don't perceive? Is there someone on the forum who can do the math that projects how the maximum-Lorentz contracted universe looks like for a photon, and apply this to an EM-drive environment?Best,CW
Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?http://en.wikipedia.org/wiki/Gravitational_redshift
Quote from: Mulletron on 05/03/2015 12:05 pmNever really thought about this before, but is light in a cavity resonator gravitationally redshifted?http://en.wikipedia.org/wiki/Gravitational_redshiftDo you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
Quote from: PaulF on 05/03/2015 12:12 pmQuote from: Mulletron on 05/03/2015 12:05 pmNever really thought about this before, but is light in a cavity resonator gravitationally redshifted?http://en.wikipedia.org/wiki/Gravitational_redshiftDo you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?
Quote from: Mulletron on 05/03/2015 12:24 pmQuote from: PaulF on 05/03/2015 12:12 pmQuote from: Mulletron on 05/03/2015 12:05 pmNever really thought about this before, but is light in a cavity resonator gravitationally redshifted?http://en.wikipedia.org/wiki/Gravitational_redshiftDo you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?Would seem to me that if the thrust produced is horizontally, gravity can't have effect on it, besides bending it a teeny weeny bit. Time dilation at beginning and endpoint are same (same distance from gravity well), so in effect 0.Vertically you could measure it, but the redshift from earth's gravity is already extremely difficult to measure, but if you could you could then detract that from the redshift value measured in the cavity.
so in effect 0.
Quote from: PaulF on 05/03/2015 12:36 pmQuote from: Mulletron on 05/03/2015 12:24 pmQuote from: PaulF on 05/03/2015 12:12 pmQuote from: Mulletron on 05/03/2015 12:05 pmNever really thought about this before, but is light in a cavity resonator gravitationally redshifted?http://en.wikipedia.org/wiki/Gravitational_redshiftDo you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?Would seem to me that if the thrust produced is horizontally, gravity can't have effect on it, besides bending it a teeny weeny bit. Time dilation at beginning and endpoint are same (same distance from gravity well), so in effect 0.Vertically you could measure it, but the redshift from earth's gravity is already extremely difficult to measure, but if you could you could then detract that from the redshift value measured in the cavity.Quoteso in effect 0.So nonzero? Say outside the bandwidth of a very narrow bandwidth cavity?
Here Shawyer compares 7 devices, some classic EMDrives, some with just a dielectic & the superconducting LN cooled Cannae drive.It is important to note the direction of generated thrust as dielectics apparently generate thrust in the opposite direction to that of EMDrives.I do note the EW test of a Cannae like device was not tested at cryo temp nor had superconducting interior lining and had an added dielectic. So was not a test of a true Cannae device.From Shawyer, EW should not expect to see any thrust from an EMDrive like test device when tested fixed, not allowed to accelerate, without added dielectic. Which is what was observed. Static thrust was not measured, with the EW EMDrive like device until a dielectic was added.Appears EW have discovered a new way to gen thrust in a fixed device. Use a dielectric. From Shawyer device summary, line 1, it appears all that may be needed is a short section of resonate pipe with a dielectic stuck in one end. IE EW Cannae test device minus the cavity. However as the dielectric thrust is weaker than the EMDrive thrust and in the opposite thrust direction to the classic EMDrive thrust direction, putting a dielectric into an accelerating EMDrive may reduce the overall delivered thrust and effective cavity Q as would be seen by the classic EMDrive operational mode.Is Shawyer giving away spoilers?
https://twitter.com/elonmusk/status/594756342641922048But why in the world did @ElonMusk link to an article from August 2014? That is soooo last year.
Quote from: Mulletron on 05/03/2015 12:32 pmhttps://twitter.com/elonmusk/status/594756342641922048But why in the world did @ElonMusk link to an article from August 2014? That is soooo last year.I don't use twitter, but perhaps you (or somebody else in the forum) does. If such is the case, can you (or somebody else) twitter him back a message informing him that this article contains much newer information ? :http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/
...I'm hopeful we can get Mr. Shawyer to participate here IF folks are civil.
Quote from: TheTraveller on 05/03/2015 11:54 amHere Shawyer compares 7 devices, some classic EMDrives, some with just a dielectic & the superconducting LN cooled Cannae drive.It is important to note the direction of generated thrust as dielectrics apparently generate thrust in the opposite direction to that of EMDrives.I do note the EW test of a Cannae like device was not tested at cryo temp nor had superconducting interior lining and had an added dielectic. So was not a test of a true Cannae device.From Shawyer, EW should not expect to see any thrust from an EMDrive like test device when tested fixed, not allowed to accelerate, without added dielectic. Which is what was observed. Static thrust was not measured, with the EW EMDrive like device until a dielectic was added.Appears EW have discovered a new way to gen thrust in a fixed device. Use a dielectric. From Shawyer device summary, line 1, it appears all that may be needed is a short section of resonate pipe with a dielectic stuck in one end. IE EW Cannae test device minus the cavity. However as the dielectric thrust is weaker than the EMDrive thrust and in the opposite thrust direction to the classic EMDrive thrust direction, putting a dielectric into an accelerating EMDrive may reduce the overall delivered thrust and effective cavity Q as would be seen by the classic EMDrive operational mode.Is Shawyer giving away spoilers?Thank you for your post, as it gives me the opportunity to ask again a couple of questions that are unanswered so far. Perhaps you can answer them:1) Shawyer reported in the above graph, that his Demonstrator engine is the only EM Drive so far that has shown forces in BOTH directions, towards the small end as well as towards the large end.1a) What does Shawyer mean by this? Does he mean that the Demonstrator engine displayed, and he measured, forces simultaneously in both directions? But as the forces in both directions are almost equal, that would mean practically no net force. That doesn't seem to make sense as the Demonstrator engine is the only one that had a force large enough that it could move the whole assembly as shown in a video:1b) Did Shawyer measure a force towards the big end in some tests and a force towards the small end in other tests? If so, what made the difference between the tests? Is the change random, unpredictable and unexplained? (Hopefully not). If the change in force direction can be deliberately controlled, how was Shawyer able to change the force direction for the Demonstrator engine? Did he have to move something? (like the location of the dielectric)? Was there a dielectric in the Demonstrator engine? Or did he just accomplish this change of force direction by changing the exciting frequency (and thereby changing the mode shape)?2) Shawyer defines the measured "thrust force" in the opposite direction to the direction of motion of the EM Drive. This is completely the opposite of NASA Eagleworks that defines the thrust force in the same direction as the motion of the EM Drive. Can you reconcile and make sense of these two opposite, contradictory definitions and measurements?Thanks
Here Shawyer compares 7 devices, some classic EMDrives, some with just a dielectic & the superconducting LN cooled Cannae drive.It is important to note the direction of generated thrust as dielectrics apparently generate thrust in the opposite direction to that of EMDrives.I do note the EW test of a Cannae like device was not tested at cryo temp nor had superconducting interior lining and had an added dielectic. So was not a test of a true Cannae device.From Shawyer, EW should not expect to see any thrust from an EMDrive like test device when tested fixed, not allowed to accelerate, without added dielectic. Which is what was observed. Static thrust was not measured, with the EW EMDrive like device until a dielectic was added.Appears EW have discovered a new way to gen thrust in a fixed device. Use a dielectric. From Shawyer device summary, line 1, it appears all that may be needed is a short section of resonate pipe with a dielectic stuck in one end. IE EW Cannae test device minus the cavity. However as the dielectric thrust is weaker than the EMDrive thrust and in the opposite thrust direction to the classic EMDrive thrust direction, putting a dielectric into an accelerating EMDrive may reduce the overall delivered thrust and effective cavity Q as would be seen by the classic EMDrive operational mode.Is Shawyer giving away spoilers?
Might be useful to listen to what Shawyer has to say:http://www.emdrive.com/interview.html