...
Dr Rodal,
is this the same arrow of time which points backward in many Feynman diagrams.
No, it is not the same as the cosmological arrow of time.
...
Dr Rodal,
Would quantum mechanics be feasible without those backward arrows?
The Schrödinger equation ( https://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation ), is time-symmetric: it has no arrow of time.
Some people make arguments about a quantum arrow of time based on wave function collapse, but this interpretation is very debatable to this date.
Concerning Feynman's idea that all electrons could in fact be the same electron, just bouncing back and forth in time, and that antimatter is actually matter moving backwards in time, it is safe to say that most physicists don't believe that antimatter is actually matter moving backwards in time. Feynman's idea inspired him to calculate what the properties of an electron moving backwards in time would be,matching the known properties of the positron. It was a useful inspiration in the 1940's. I don' think that Feynman insisted on that idea as something physical, particularly later on in his career, in the 1960's and later.
Time...
.evitcepsrep fo rettam a s'ti sseug I gniog m'I yaw hcihw erus ton m'I emitemoS
llehS
Shell, it looks like the temporal coupler on your rig is a little leaky. Remember everybody, safety is the watchword on these DIY efforts. Paradoxes are to avoided at ALL costs!
I just had a probably dumb idea, but here goes.
Speed is v(t) = dx/dt . Momentum p(t) = m*v(t) . In Earth lab setups, both lab and test article start out with the same speed and direction, so there is no relative movment. But, Earth and test article move relative to the rest of the universe. What, if the active test article ever so slightly locally changes the progression of what we call time?
Time slows down: p(t) = m*v(t) = m*dx/dt increases, thus a force can be measured.
Time speeds up: p(t) = m*v(t) = m*dx/dt decreases, thus a force can be measured.
The force would be created by the test article pushing or pulling on Earth's mass, relatively speaking.
We are always looking at conservation of energy and momentum. But is there a principle of 'conservation of time' in physics? And could this be broken, if local time were an entropy-like entity?
I don't know about 'conservation of time', but what you say is more like standard physics than a dumb idea.
Working through the Schwartzschild solution in the weak-field approximation for slowly moving bodies shows that the metric corresponding to Newtonian gravity is exactly one where just the rate of passage of time is perturbed slightly. See this paper:
http://gfm.cii.fc.ul.pt/events/lecture_series/general_relativity/gfm-general_relativity-lecture4.pdf in particular the Newtonian Gravity metric in the middle of page 11.
Note that the acceleration due to gravity on the earth's surface is due to a perturbation of order 10^-9.
Since we are looking for EMdrive forces around g*10^-3 to g*10^-2, the perturbation to time required to explain that force would likely be much smaller than 10^-9.
Which only leaves the impossible question as to how to change the flow of time!
R.
It's interesting to know though and do you see the same using the waveguide being parallel to the side wall?
Here is a link for some close ups of the magnetron antenna and I just mic'd it out for you.
http://imgur.com/a/6C9yu
http://imgur.com/8LsmKCj
Thanks so much Shell! I plan on running sims using a waveguide as well. Will let you know what I see.
It's interesting to know though and do you see the same using the waveguide being parallel to the side wall?
Here is a link for some close ups of the magnetron antenna and I just mic'd it out for you.
http://imgur.com/a/6C9yu
http://imgur.com/8LsmKCj
Thanks so much Shell! I plan on running sims using a waveguide as well. Will let you know what I see.
On one of my last runs before I tore it down again I didn't see much of a difference in the waveguides being at the frustum sidewall angle or parallel to the bottom plate. I will be interesting to see what FEKO comes up with.
I machined out the supports yesterday to allow for changing the distance of the balance beam vertically, this allows different sized drives to be tested and to support a inverter magnetron on the beam or isolated above it. More holes and screws and nuts needed to be added, but you can see how the basic setup looks. I hope today to get the holes drilled and the inverter magnetron box mounted on the top assembly.
Shell
It's interesting to know though and do you see the same using the waveguide being parallel to the side wall?
Here is a link for some close ups of the magnetron antenna and I just mic'd it out for you.
http://imgur.com/a/6C9yu
http://imgur.com/8LsmKCj
Thanks so much Shell! I plan on running sims using a waveguide as well. Will let you know what I see.
On one of my last runs before I tore it down again I didn't see much of a difference in the waveguides being at the frustum sidewall angle or parallel to the bottom plate. I will be interesting to see what FEKO comes up with.
I machined out the supports yesterday to allow for changing the distance of the balance beam vertically, this allows different sized drives to be tested and to support a inverter magnetron on the beam or isolated above it. More holes and screws and nuts needed to be added, but you can see how the basic setup looks. I hope today to get the holes drilled and the inverter magnetron box mounted on the top assembly.
Shell
Shell, your testbed is obviously well thought out. I can tell just by the aluminum base plate. Now, for future consideration, something I mentioned several threads ago...you should consider offering your test stand for any and all emdrive prototypes. My thought on this goes beyond uniformity of testing, but as a single place to test a variety of factors, specifically CE style E & H testing. Now, this is a high-level, multi-axis test best done in open spaces. Its a static test, meaning a torsion balance or fulcrum is not needed, but power-up is. Typically, it needs a 10 channel datalogger to be safe.
This is for down the road, obviously, but as you're configuring the test stand, think big...
Global Emdrive Test Lab. Could lead to lots of other fun things, maybe vacuum testing. Keep this in the back of your head...what you're doing looks excellent.
It's interesting to know though and do you see the same using the waveguide being parallel to the side wall?
Here is a link for some close ups of the magnetron antenna and I just mic'd it out for you.
http://imgur.com/a/6C9yu
http://imgur.com/8LsmKCj
Thanks so much Shell! I plan on running sims using a waveguide as well. Will let you know what I see.
On one of my last runs before I tore it down again I didn't see much of a difference in the waveguides being at the frustum sidewall angle or parallel to the bottom plate. I will be interesting to see what FEKO comes up with.
I machined out the supports yesterday to allow for changing the distance of the balance beam vertically, this allows different sized drives to be tested and to support a inverter magnetron on the beam or isolated above it. More holes and screws and nuts needed to be added, but you can see how the basic setup looks. I hope today to get the holes drilled and the inverter magnetron box mounted on the top assembly.
Shell
Shell, your testbed is obviously well thought out. I can tell just by the aluminum base plate. Now, for future consideration, something I mentioned several threads ago...you should consider offering your test stand for any and all emdrive prototypes. My thought on this goes beyond uniformity of testing, but as a single place to test a variety of factors, specifically EC style E & H testing. Now, this is a high-level, multi-axis test best done in open spaces. Its a static test, meaning a torsion balance or fulcrum is not needed, but power-up is. Typically, it needs a 10 channel datalogger to be safe.
This is for down the road, obviously, but as you're configuring the test stand, think big...Global Emdrive Test Lab. Could lead to lots of other fun things, maybe vacuum testing. Keep this in the back of your head...what you're doing looks excellent.
You may be just reading my mind rfmwguy.
To do that I realized a bit ago I needed more flexibility not only for the frustums I'm testing but maybe others as well. I have been approached and asked but can't release details.
I know I also need to acquire some more basic equipment then what I have. Modifying what I have now with the test bed to go in that direction is just good planning not only for me and what I'm building but maybe others.
As we say it's a work in progress.
Shell
added... Thanks!
Let's assume that the EMDrive is a form of photonic laser thruster for a minute (it's not).
Why?
Because at the time I wrote that, I could not see a way that photons bouncing inside the frustum would not create an equal force on both ends. Additionally a photonic laser thruster operating at the power level of an EMDrive would generate a much greater force than has currently been reported. Remember that W in 2NW/C is the OUTPUT power of the laser. (Personally, I hope Bae gets a change to experiment with a Maser and a solid state gain medium). Coupled with Rodal's observation that, while frustum without a dielectric tended to show a greater force in air, those with a dielectric show a greater force in a vacuum, this led me to suspect that I might have stumbled onto a way to explain CoE with a Woodward effect drive.
The I went back to bed and realized that, if light lag were causing photons to be received prior to the devices acceleration entering the light cone of the reflector (and I might be wrong to think that this condition can even exist), then some amount of photons might not make the return trip, but instead be absorbed by the large endplate. This would mean that the amount of kinetic energy generated by the small endplate would be larger than the amount of kinetic energy generated by the same effect applied going the other direction. I need to sit down and put some serious thought into how this might look as it is not, intuitively, clear that the force would be greater than that of a photon rocket.
Just a thought about CoE:
...
As I showed in an earlier post, W/c means that the same amount of energy is redshifted out to produce momentum regardless of the velocity of the photon rocket.
However, as I also showed, this does not* produce an over-unity. Instead, the acceleration causes a doppler shift in the emitted light such that the doppler shifted light loses energy equal to the kinetic energy gained by the photon rocket.
...
* Actually the well-established, mainstream equations did show a small overunity at high speeds. Why this should be the case is a, very, interesting questions.
You apparently missed my previous post that pointed out that you used the wrong equations in the wrong context.
Short version: Redshift of an emitted photon is the difference in energy of the photon between 2 different reference frames, but CoE does not apply across reference frame transformations. (Note this is different than redshift of a reflected photon, in which case both photon frequencies are measured in the same reference frame.)
I will go back and have a look at that (I thought I got no response). If I am wrong, that creates a certain difficulty. If a photon rocket F=w/C, then that would that not imply that the light in question is redshifted by w/C. If w=C then would that not apply a force of 1 Joule is redshifted out of the emitted light to generate 1 Newton of acceleration? Assuming a photon rocket with an initial speed of 100,000 m/s and accelerating to 100,001 m/s with a weight of 1kg, KE=1/2mv^2 says that its kinetic energy must increase by 100,001 Joules. (Please note m/s not km/s as I accidentally stated in my prior post.) I have assumed that Doppler shift is the mechanism for dealing with the CoE violation.
If not, can somebody please explain what I've done wrong as F=w/C is implying constant acceleration for constant power which is causing an apparent over-unity.
In case anyone is interested, this is what Iulian Berca's dimensions did at 2.459 GHz.
Bottom diameter 11.01 in
top diameter 6.25 in
height 9 in
antenna placement 1.35 in from the bottom
Not sure what mode this is, but I'm going to play with the dimensions more to find the TE013.
I've been thinking of ditching the waveguide and going to Iulians design because hanging a frustum with a waveguide that has a magnetron mounted on it is complicated.
...
Dr Rodal,
is this the same arrow of time which points backward in many Feynman diagrams.
No, it is not the same as the cosmological arrow of time.
...
Dr Rodal,
Would quantum mechanics be feasible without those backward arrows?
The Schrödinger equation ( https://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation ), is time-symmetric: it has no arrow of time.
Some people make arguments about a quantum arrow of time based on wave function collapse, but this interpretation is very debatable to this date.
Concerning Feynman's idea that all electrons could in fact be the same electron, just bouncing back and forth in time, and that antimatter is actually matter moving backwards in time, it is safe to say that most physicists don't believe that antimatter is actually matter moving backwards in time. Feynman's idea inspired him to calculate what the properties of an electron moving backwards in time would be,matching the known properties of the positron. It was a useful inspiration in the 1940's. I don' think that Feynman insisted on that idea as something physical, particularly later on in his career, in the 1960's and later.
Thanking you Dr Rodal,
next question, didn't George Smoot show that space is flat, with Boomerang?
I've regularly read this thread for quite a long time, but I have been unable to read it all lately. Please humor me as I ask a question out of lack of time: What happened to Shell's test that worked before burning out? I thought she was replacing the burnt out part and retesting in a different location? Did something else go wrong? Did I just miss the results?
Thanks!
David
I've regularly read this thread for quite a long time, but I have been unable to read it all lately. Please humor me as I ask a question out of lack of time: What happened to Shell's test that worked before burning out? I thought she was replacing the burnt out part and retesting in a different location? Did something else go wrong? Did I just miss the results?
Thanks!
David
You picked a good time to rejoin. Shell is running tests now with a reconfigured test stand and emdrive. She will be posting results soon.
Tangent - Couldn't find an NSF topic on Antimatter Space Propulsion so thought I'd link this here for others to possibly start the topic.
"Antimatter Space Propulsion Possible Within A Decade, Say Physicists
Dreams of antimatter space propulsion are closer to reality than most rocket scientists could ever imagine, says former Fermilab physicist Gerald Jackson. In fact, if money were no object, he says an antimatter-driven spacecraft prototype could be tested within a decade. To that end, next month, Jackson and his Chicago-based Hbar Technologies firm are launching a $200,000 Kickstarter campaign to crowdfund the next phase of its antimatter propulsion research."
http://preview.tinyurl.com/grv8ljj
http://www.hbartech.com/Blowing your own sail? Hmmmmm.
In case anyone is interested, this is what Iulian Berca's dimensions did at 2.459 GHz.
Bottom diameter 11.01 in
top diameter 6.25 in
height 9 in
antenna placement 1.35 in from the bottom
Not sure what mode this is, but I'm going to play with the dimensions more to find the TE013.
I've been thinking of ditching the waveguide and going to Iulians design because hanging a frustum with a waveguide that has a magnetron mounted on it is complicated.
I got very similar results from FEKO.
....
http://preview.tinyurl.com/grv8ljj
http://www.hbartech.com/
Blowing your own sail? Hmmmmm.
It would be misleading to think "blowing your own sail?" referring to this concept. This may confuse people in the EM Drive thread (given Shawyer's explanation for the EM Drive as a closed system defying conservation of momentum).
This concept is not at all "blowing your own sail". This concept is
conventional rocket propulsion, fully satisfying conservation of momentum.
Antiprotons induce fission in the uranium 238 layer on the sail with 100% efficiency, where the Uranium 238 get ejected from the sail. The ejecta of fission products from Uranium 238 coating from the sail is what allows propulsion. Unlike the EM Drive explanation by Shawyer, which does NOT make any sense whatsoever (Shawyer proposes a closed system where no energy and no mass escapes), this concept relies on ejecting Uranium from the sail, for propulsion.
This concept, rather than making one think that Shaywer's explanation is possible, does all the contrary: it shows once again that to enable rocket propulsion, even using matter-antimatter reaction, the most effective way is to use propellant: ejection of mass (in this case, ejecting the fission products from the Uranium 238 coating on the sail).
Please read the original papers:
The basic nuclear physics behind this concept is the fact that antimatter incident on the surface of an uranium foil has a 98% probability of inducing a fission event.
....
In undergoing fission it is found that two fragments of approximately palladium-111 are emitted back-to-back with a total energy of approximately 190 MeV. The velocity of the fission products is 1.39x107 m/s and the mass is 1.85x10-25 kg/atom. This velocity would equate to a specific impulse of 1.4 million seconds
...
In principle any material can be used as a backing layer to the uranium foil to provide this stopping power. Note that toward the end of life of the foil, its thickness will be much reduced and a high-strength, high melting point material is desired. We have chosen carbon for these reasons
In case anyone is interested, this is what Iulian Berca's dimensions did at 2.459 GHz.
Bottom diameter 11.01 in
top diameter 6.25 in
height 9 in
antenna placement 1.35 in from the bottom
Not sure what mode this is, but I'm going to play with the dimensions more to find the TE013.
I've been thinking of ditching the waveguide and going to Iulians design because hanging a frustum with a waveguide that has a magnetron mounted on it is complicated.
I got very similar results from FEKO.
Hate to trouble you, but Aero ran out of time to model my new frustum. Would you be able to give it a shot? It is:
Big Dia: 10.0 in
Small Dia: 6.25 in
Height: 8.0 in
Antenna placement: axially centered monopole (not dipole) on Big Dia. Tip of monopole about 1 inch depth into cavity. Cavity ground is other half of monopole.
Really appreciate it. - Dave
To do that I realized a bit ago I needed more flexibility not only for the frustums I'm testing but maybe others as well. I have been approached and asked but can't release details. 