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To: Maurice Winn who wrote (136525)11/4/2017 5:18:07 PM
From: TobagoJack  Respond to of 217549
 
re <<self referential boot-strapping in a closed system>>

emdrive en.wikipedia.org seems to do that, and there may be a good reason, but i simply do not truly understand it, because it is so different

sciencealert.com

This Overlooked Theory Could Be The Missing Piece That Explains How The EM Drive Works



Ever since the EM drive first made headlines, science lovers have puzzled over how the propulsion system seems to produce thrust, despite the fact it's 'impossible' according to one of the most fundamental laws of physics - Newton's third law of motion.

Now a team of physicists have put forward an alternative explanation - it turns out the EM drive could actually work without breaking any scientific laws, if we factor in a weird and often overlooked idea in quantum physics - pilot wave theory.

For those who need a refresher, the crux of the problem here is that the EM, or electromagnetic, drive appears to produce thrust without any fuel or propellant.

That's awesome because it means we can get to space with way less pay load - it's proposed it could even get us to Mars within 72 days.

But it's also perplexing, because, according to Newton's third law, every action must have an equal and opposite reaction. So without pushing any propellant out one end, the drive shouldn't be able to produce thrust in the opposite direction.

Still, as a NASA peer-reviewed paper showed last year, the drive does produce thrust, at least as far as we can currently tell. And a relatively large amount of thrust at that. We just don't know how.

So either our understanding of physics isn't right, or we're missing a big piece of the puzzle when it comes to the EM drive.

A new paper published in The Journal of Applied Physical Science International makes the argument that what we're missing is pilot wave theory - a slightly controversial alternative interpretation of quantum mechanics.

Researchers José Croca and Paulo Castro from the Centre for Philosophy of Sciences of the University of Lisbon in Portugal suggest that not only could pilot wave theory explain the mysterious behaviour of the EM drive, it could help to make it even more powerful.

"We have found that applying a pilot wave theory to NASA's EM drive frustum [or cone], we could explain its thrust without involving any external action applied to the system, as Newton's third law would require," Castro told ScienceAlert via email.

So what is pilot wave theory? Currently, the majority of physicists subscribe to the Copenhagen interpretation of quantum mechanics, which states that particles do not have defined locations until they are observed.

Pilot wave theory, on the other hand, suggests that particles do have precise positions at all times, but in order for this to be the case, the world must also be strange in other ways – which is why many physicists have dismissed the idea.

But in recent years, the pilot wave theory has been increasing in popularity. The team has shown in its latest paper this theory could be tweaked slightly to apply to something bigger. Say, the EM drive. And it could explain the results we've been seeing.

Basically, pilot wave theory says that an object radiates a wave field, and it is then pulled or attracted to regions of that field that have higher intensity or energy density. In that way, the wave field is actually 'piloting' the object, hence the name.

Through modelling, the team showed that a sufficiently strong and asymmetrical electromagnetic field could act as a pilot wave. And that's exactly what the EM drive generates.

Because the cone, or frustum, of the EM drive is asymmetrical, it would also generate an asymmetrical wave field. As a result, the walls of the EM drive would move towards the areas of higher intensity, creating thrust.

While that might sound pretty out there, this was also actually a possible solution put forward by the NASA Eagleworks researchers in their seminal paper last year where they first reported the thrust generated by their device:

"[The] supporting physics model used to derive a force based on operating conditions in the test article can be categorised as a nonlocal hidden-variable theory, or pilot-wave theory for short."

To be clear, the researchers from the University of Lisbon haven't tested their proposal in a real device as yet.

They've only shown that it's possible, from a modelling point of view, for a pilot wave to guide the EM drive. But they've also shown how the idea could actually be tested in future.

"At the moment the most stringent empirical evidence comes from the EM drive behaviour," Castro told ScienceAlert. "However, we have also devised an experiment to detect and modulate subquantum waves."

Importantly, if the hypothesis is confirmed, it would mean the EM drive would not have to break Newton's third law. And the team hopes this might result in the device being taken seriously and more widely tested.

"EM drive is the future of space propelling motors," they said. "[Although] it will perhaps find its initial application in nano satellites or nano drones, at least before the effect can be scaled up to heavier machines."

Importantly, if a pilot wave does explain the thrust behind the device, then it could also lead to a way to make the propulsion system even more powerful in future, and it's as simple as tweaking the shape.

"We have seen that the effect could be enhanced using a different shape for the frustum," said Castro. "In fact a trumpet exponential form is expected to increase the thrust."

The team is now considering building its own experimental set up to study the phenomena and has invited anyone interested in the project to get in touch.

In the meantime, the NASA Eagleworks team continues to test out its device. And there are also groups looking to test the EM drive in space - or according to some rumours, already doing so - which would really show once and for all whether it works.

There's a lot we have yet to learn about the mysterious EM drive and it's a topic that continues to divide the science world. But whether or not it ends up being the future of space travel, at least it's teaching us more about the physics that govern our world.

The new research has been published in The Journal of Applied Physical Science International.



To: Maurice Winn who wrote (136525)11/4/2017 5:21:40 PM
From: TobagoJack  Read Replies (1) | Respond to of 217549
 
... but sometimes it may be best to simply let the techies tinker even as the desktop folks try to figure out the why's



gearsofbiz.com

Have physicists solved NASA’s ‘impossible’ EmDrive?
4 November 2017

Scientists around the world are working to develop the first ‘reactionless’ propulsion system – a so-called impossible engine that could slash space-travel times and reduce the costs of future missions.

But, many argue a theoretical EmDrive system that uses a microwave field to generate thrust defies the fundamental laws of physics, and could never be brought to life.

New research over the last year, however, now suggests scientists may finally be getting closer to uncovering how the ‘impossible engine’ could work, according to theoretical physicist Giulio Prisco.

The most recent, published by scientists in Portugal, claims a type of ‘pilot wave’ theory could explain the ‘strange’ quantum-like behaviour seen in the experiments.

In the new study, led by researchers at the University of Lisbon, the team proposes an explanation designed to bridge the gap between quantum and macroscopic systems – a current challenge in the feasibility of the EmDrive.

By the pilot wave theory, bouncing fluid droplets on a vibrating fluid path create what’s known as a pilot-wave field, Prisco explains in an article for Motherboard.

This field then guides the motion of the droplets.

This explanation relies on a nonlinear approach, the authors explain in the study, in which the thrust can be explained as a consequence of the field intensity as it interacts with the particles in the device.

Under the right conditions, such as those in the proposed EmDrive device, the researchers argue that such a system can eschew Newton’s third law, which states that for every action, there is an equal and opposite reaction.

‘Consequently, since we are in the nonlinear realm it may happen that, in general, action does not equal reaction, even taking into account the intermediary of fields,’ the authors argue.

‘This means that in certain specific conditions a minor action may give rise to a huge reaction.’

Over the last few years, researchers have proposed several explanations for the impossible engine, with efforts ramping up after a NASA paper appeared to show scientist had successfully created a working EmDrive prototype.

While some initially cited a ‘quantum vacuum theory’ to explain the findings, others claim a phenomenon known as the ‘Mach effect’ could be to blame.

By this effect, which was first theorized in the 1990s by physicist Jim Woodward, some of the force applied to an accelerating body of mass is stored as potential energy in its body rather than generating kinetic energy, according to Motherboard.

A new propaganda video claims that scientists in China have created a working prototype of the ‘impossible’ fuel-free engine.

The radical EmDrive has been hypothesised for years by Nasa, but the space agency has been unable to create a working version.

If the physics-defying concept is brought to reality, it’s said the engine could get humans to Mars in just 10 weeks.

The video was posted by CCTV.com, and is titled ‘Propellantless propulsion: The Chinese EmDrive by CAST scientist Dr Chen Yue, China’s Space Agency.’

It claims that Chinese scientists have developed the EmDrive, and will soon put it into space – although it does not state any technical aspects of the device.

The EmDrive is an engine that provides thrust without the need for fuel.

Instead, it bounces microwaves – provided by solar energy – around in a closed container.

With no fuel to eject, the EmDrive would violate Newton’s third law, which states that for every action, there is an equal and opposite reaction.

This isn’t the first time that China has claimed to have made a working EmDrive.

This causes fluctuations in the object’s resting mass, and this effect could be harnessed to create the type of thrust seen in the experiments.

Earlier this year, NASA’s Innovative Advanced Concepts (NIAC) program funded a project based on this effect.

And, this summer, a Chinese propaganda video claimed scientists in China have created a working prototype of the ‘impossible’ fuel-free engine.

Despite claims that the device would soon be put into space, the video did not reveal any technical aspects of the system.

While the impossible engine remains controversial, experts say it has potential to revolutionize space travel – if it is ever truly brought to life.

‘If the reaction-free EmDrive works, it would open the door for reaction-free space missions, which could reach the planets in weeks instead of months, and at a much lower cost,’ writes

‘It could ultimately open a path to the stars.

‘Therefore, it’s not surprising that visionary engineers continue to pursue the experimental and theoretical EmDrive research, despite the controversial nature of the technology.’




To: Maurice Winn who wrote (136525)11/9/2017 7:47:06 AM
From: TobagoJack  Respond to of 217549
 
neat stuff bbc.com