NASA EmDrive Paper Peer Reviewed |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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Posted: 22 Nov 2016 at 12:32pm |
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This may shock anyone familiar with Newton's third law!
For every action there is an equal and opposite reaction. Expel jet thrust backward and the aircraft moves forward. Paddle water backward and the canoe moves forward. Well meet NASA's EmDrive, it expels nothing at all but according to NASA's extensive research, now peer reviewed, it still generates thrust. Not much thrust, but in a vacuum, carrying zero propellant, enough to be significant. NASA's EmDrive is said to work by bouncing microwave photons around in a come shaped chamber. As the photons collide with the walls of the chamber they somehow propel the device forward. It's a bit like banging your fists against the steering wheel in your car and somehow expecting the car to move forward. It won't of course, but in a vacuum NASA say the EmDrive does. Scientists of course have been beyond sceptical that such a drive could work, as it defies the known laws of physics, but that hasn't stopped several teams testing the idea. US, UK and European teams, not to mention DIY enthusiasts have conducted experiments but up until now no one has been able to prove the device works. Whats significant now through is that NASA's research is peer reviewed. Peer review doesn't of course guarantee that NASA's findings are valid, but it does tell us that several independent scientist's have looked at NASA's research and deemed it to be conducted correctly. It also tells us that NASA's experienced researchers are convinced it works. So convinced in fact that over the coming months, NASA will be testing the device in the vacuum of space. The NASA Eagleworks Team seem to be convinced that the device somehow pushes against the quantum vacuum itself, against quantum vacuum virtual plasma. NASA suggest that Pilot Wave theory explains how the device achieves this. This isn't like, for example, climate change, which has something like 1500 peer reviewed scientific papers to back it up, this is just one peer reviewed paper, so of course once other researchers attempt to replicate the results errors could be found. However, if it turns out to be valid, expect a trip to Mars in 70 days, outer reaches of the solar system in months! http://www.sciencealert.com/it-s-official-nasa-s-peer-reviewed-em-drive-paper-has-finally-been-published |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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The peer-reviewed paper... http://arc.aiaa.org/doi/10.2514/1.B36120
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hifly
Chief Pilot Joined: 04 Jan 2012 Location: Hastings UK Points: 1012 |
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Blimey Martin, I didn't understand a word of that.
Still, it's good to know that you are warm and vertical.
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Must Fly!
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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Just whacks a load of microwaves around in a big copper can basically.
Apparently the NASA team knocked it together in their dining hall, just to see if it would work. Of course they were shocked when it (apparently) did. So it's not optimised at all, very makeshift. If this copper tin can is really doing what NASA think, then Newton was wrong, Einstein was wrong, Maxwell is wrong and actually quantum physics is wrong. Most likely scenario is that NASA missed something, something conventional in the experiment that accounts for the thrust. Interestingly though there have been several teams from around the world that have experienced similar results. Mouths around the world will be gaping if they find when they get it in space is actually works. The next few months will be very interesting. Roger Shawyer has been claiming for years it works. My view is that there's a miniscule chance it really does what they think. Having said that though, there's so much we don't understand, dark matter, dark energy etc. Basically its cleared it's first credibility hurdle, but more hurdles to negotiate. http://www.forbes.com/sites/startswithabang/2016/11/23/how-physics-falls-apart-if-the-emdrive-works/#2824c7fb4b0c |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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And okay, get this.... they claim they may have accidentally created a warp bubble! NASA researchers posted on a NASA space flight forum that when they fired lasers into the chamber, the photons appeared to travel faster than light. So they claim they may have created a warp bubble. In fact, not just NASA, all three independent teams that experimented with this device claim the math behind the "warp bubble" matches the interference pattern found in the EmDrive! The acceleration is consistent with the warped space seen in an Alcubierre Drive [warp drive]. Beam me up scotty!
https://www.extremetech.com/extreme/227146-a-new-theory-of-inertia-could-explain-the-em-drives-anomalous-thrust
https://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field_interferometer |
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garyscott
Check-In Staff Joined: 10 Oct 2016 Points: 17 |
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This was several years ago. It is "theoretically" possible, but those involved have been incredibly quiet about the costs involved in the A-drive.
Its not a flat fantasy, but its not in any way possible anytime soon. |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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A-Drive? Never heard of it.
Any more info, links? In regard to the EmDrive, it's most definitely not theoretically possible. Hence the numerous attempts to find something that the researchers have missed. If it does turn out to be valid, we will need to rewrite the text books. There have been a few attempts to explain how the EmDrive achieves the seemingly impossible. Pilot Wave Theory, Unruh radiation and more recently, suggestions that it does actually have an exhaust, namely photons we can't detect. ..
'EmDrive works just like any other engine,' Dr Arto Annila, physics professor at the University of Helsinki and lead author of the paper, told MailOnline. 'Its fuel is the input photons at microwave lengths.' The researchers suggest the photons coming out of the machine interfere with each other, so that the overall effect seems as if nothing is there. 'In the cavity the input photons will bounce back and forth, and invariably some of them will interfere completely destructively. Then the two photons will be exactly 180 degrees out phase. At the complete interference electromagnetic fields for the two photons will cancel exactly, but the photons themselves continue to propagate.' The idea is the same as water waves travelling together, at the exact right time so that the crest of one wave is exactly at the trough of the other and cancelling each other out. The water does not go away, it's still there. In the same way the pairs of photons are still there and carrying momentum even though they cannot be seen as light. The paired photons without net electromagnetic field will escape from the cavity,' Dr Annila said. 'This efflux of paired photons is the exhaust of EmDrive.' 'When the cavity is asymmetric, like the tapered cone, the efflux of paired photons is also asymmetric. Therefore the loss of momentum carried by the paired photons is uneven. In other words, thrust is non-zero.' Dr Annila came up with the idea along with Dr Erkki Kolehmainen, an organic chemistry professor at the University of Jyväskylä and Patrick Grahn, a multiphysicist at engineering software firm Comsol. 'Thrust without exhaust is of course impossible,' the authors wrote in their. 'Yet, certain resonant cavities, when fueled with microwaves, deliver thrust without apparent exhaust.' Their theory suggest the exhaust produced by the EmDrive is there, but just cannot be seen. Dr Annila said the photons could theoretically be detected by an interferometer, the same instrument used to detect gravitational waves. 'My gut feeling is that it will be very difficult to detect such a small excess in energy density, especially when operating EmDrive steadily,' he said. 'Namely changes are more amenable to detection in any case. But still our idea about the exhaust can be useful to design the cavity for pairing photons better for an exit in a preferred direction, and hence to generate more thrust.' http://www.dailymail.co.uk/sciencetech/article-3644747/Does-Nasa-s-fuel-free-thruster-invisible-exhaust-New-theory-explain-EmDrive-man-Mars-10-weeks.html |
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garyscott
Check-In Staff Joined: 10 Oct 2016 Points: 17 |
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Meant as following on from your post regards the Alcubierre drive tech. There was an (unverified) period of what, for all intents and purposes, was a short period during testing of EMdrive theory on a development "item", of what bears the expected hallmarks of A-drive initialisation.
Regretably, or maybe just hushed up, the test has not been repeated. That is public domain anyway . . . |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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Oh right, sorry, not heard of Alcubierre's speculative warp drive idea referred to as an A-Drive before, warp drive yes. It was actually April 2015. Since then, Shawyer himself has stated that the device has nothing to do with warp drive. And n fact he claims in the video below that it does indeed comply with Newton's third law. He tells us EmDrive IS based on classic physics, the theories of Maxwell, Newton and Einstein. Others obviously disagree. |
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MarkH
Chief Pilot Joined: 03 Apr 2008 Location: UK Points: 1570 |
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Hi All,
This is pretty cool stuff, scientists realising they know next to nothing about reality. I hope this experiment works in space as I remember reading about this a few years ago in a NASA engineering forum. Could this have something to do with non zero energy in quantum systems? That's my bet
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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This is pretty cool stuff, scientists realising they know next to nothing about reality.
Except that the most likely scenario Mark, is that they have indeed missed something. Shawyer himself tells us that there's no physics defying stuff going on at all. He seems to think Newton's third law isn't violated at all, in fact relies on it. [See video]. Quite clear that no one else believes that though. It will be fantastic if it all pans out in space, but I certainly wont be betting any dosh. |
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MarkH
Chief Pilot Joined: 03 Apr 2008 Location: UK Points: 1570 |
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"Except that the most likely scenario Mark, is that they have indeed missed something".
Hi Martin, Hope you and yours are well. Yep, they have missed something truly fundamental, which is why I said they know next to nothing. This isn't a bad thing, but a case of the more we learn the more we realise we don't know. Physics and science in general is strewn with this problem. Science's aim is to explain the why's! Everything else are just place holders until more understanding and discovery happens, science currently doesn't answer many why's unfortunately. |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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No Mark I meant in terms of an experimental error. In terms of a conventional explanation for the effect detected.
It's very unlikely that they've discovered anything new... but lets hope so. There are lots of ways they could have inadvertently messed up. Thermal expansion of the device could account for the results. They haven't eliminated all possible sources of error. As you know, peer review just means that the methodology seemed reasonable to those that reviewed it... not that the results are valid. Most of the scientists that have looked at this are sceptical, we should be too. Newton, Maxwell and Einstein have been proven correct many times, it's likely they are still correct. Shawyer claims it doesn't defy Newton Einstein and Maxwell of course and says it works as follows... Electromagnetic waves have no mass, but do have momentum, that momentum is transferred to the reflecting surfaces and produces a force called radiation pressure... |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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This is a really fascinating video, where Shawyer explains the history of the drives development. The idea originally spawned from a Royal Institute Christmas lecture in the 70's by Eric Laithwaite, concerning gyroscopes.
https://en.wikipedia.org/wiki/Eric_Laithwaite I actually watched that very lecture on TV and was fascinated by Laithwaite's theories. Whether he's right or wrong, Shawyer fascinates me, just as Laithwaite did back in the 70's. |
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Christopher Low
P/UT Joined: 07 Nov 2011 Location: Ulverston UK Points: 162 |
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How can anything with no mass have momentum?
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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It's a while since I looked at this and Mark will probably have a better explanation, but the answer is... Because it travels at the speed of light! A photon has no rest mass, but still has momentum. It's been experimentally verified. It must travel at precisely light speed to have momentum. It has been theorised that this is going on with the Shawyer device. Namely that photons are emitted, and that's actually the exhaust....
"That's the same as water waves travelling together so that the crest of one wave is exactly at the trough of the other and cancelling each other out. The water does not go away, it's still there, in the same way the pairs of photons are still there and carrying momentum even though you can't see them as light. "If you don't have electromagnetic properties on the waves as they have cancelled each other out, then they don't reflect from the cavity walls anymore. Instead they leak out of the cavity. So we have an exhaust – the photons are leaking out pair-wise." http://www.ibtimes.co.uk/emdrive-finnish-physicist-says-controversial-space-propulsion-device-does-have-exhaust-1565673 |
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MarkH
Chief Pilot Joined: 03 Apr 2008 Location: UK Points: 1570 |
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How can anything with no mass have momentum?
In classical physics it's a bloody good point Chris, but in relativistic physics (special relativity in this case) Einstein postulated that energy and mass are the same thing (mass-energy equivalence), just measured in different units. The energy of a photon is treated the same as mass, and you can multiply energy and velocity to calculate a photons momentum. Photons have mass inversely proportional to their wavelength and have relativistic mass proportional to their momentum. Looking at photons in this way explains why they are effected by gravity and bend around large masses like the sun. The mass is expresses simply as energy. You can also think of the mass of a photon in a different way, as 'rest mass' or 'invariant mass'. This has more to do with general relativity and is termed invariant mass because it is unchanging regardless of the observers point of view (for example, if an observer says the 'photon is at rest or is moving'). As a photon for every observer always moves at the speed of light in a single direction, the maths shows that the mass for a photon must be zero as Martin stated above. Think of it as all the mass of the photon is expressed as energy that enables it to travel at light speed. Looking at it in this way, photons curve around the sun because they are travelling the straightest line in curved space. Of course, this may all be total balls Cheers, M. |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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Interesting development...
It's been suggested that Boeing's top secret spy plane, the X37, is already testing an EmDrive. Would kind of make sense given that Boeing were about to sighn a deal with Shawyer but mysteriously they dropped out without a word. Almost as if they decided it was a valid idea and developed their own instead.
http://www.ibtimes.co.uk/space-race-revealed-us-china-test-futuristic-emdrive-tiangong-2-mysterious-x-37b-plane-1590289 |
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