UFO propulsion, metric engineering, and horizon physics

[Realm]

Basic science has yet to be done. Every single one I've talked to say the AC drive likely won't work in reality. Every one I've talked to say that much of the things you point as done are in fact not done, not repeatable, not tested or proven, and some aren't testable at all.

So no surprise there.

The ones I've talked to say that you can't engineer the tensor at all in ways that you describe.

So no surprise there either.

But obviously it's a conspiracy, and most of the world is part of it.

I never once said that I don't believe in QM.

Doesn't matter. In this conversation it's Thomas who specifies what each of us said or even thought. I have never been so surprised upon hearing my own thoughts.

 

[DROBNJAK]

Put the papers down and describe how you'd engineer the tensor to produce the effects you want in a material that exists in the universe. Using energetic states known to exist in the universe. And what exactly you predict it would do.

Transistor doesn't exist in universe, not even steel or bronze exist in the universe. And list goes on integrated circuits, superconductors and meta-materials.

We are talking here is something mathematically possible, not is it engineerable.

Mathematics discovered anti-matter. Anti-mater was so far out that it didn't exist even in science fiction.

And if you want time crystals, were recently invented by Frank Wilchek from pure mathematical solution. If Wilcheck was not a Nobel laureate and didn't have such a strong brand, I am sure that a ton of negativists would just berry him alive.

If negative mass is supported with a good solid mathematical deviation, it will be made in a physical form, even if we need to wait 100-500 years and even if we need to assemble it molecule by molecule.

But you are sidetracking the whole thread. This thread is to discuss metric engineering in "near horizon" of modern science. Like, the next big thing format. If you know of some good science papers on this subject please contribute. If you don't, why don't you start another thread and discuss your own points.

You are ruining it for everybody else who wants to get more information on this subject.

 

[Realm]

I haven't really been eager to go into the details of those metamaterials, as there's really no point, since there's not even a single credible source for the sort of ideas that have been discussed here. But since they in themselves are interesting, let's see if we can actually turn this conversation from this technobabble below into something that could be understandable and useful for wider audiences:

he (Puthoff) raises an interesting untested possibility that such thin layers of these metals could act as a waveguide for terahertz waves, and exhibit a negative refractive index. And a negative refractive index invokes a little-known possibility with regard to generating a negative Poynting vector, and a negative Maxwell stress tensor at a boundary, which would produce a series of negative terms in the electromagnetic stress-energy tensor - and this would indeed produce a drop in inertial mass

First, I would like to mention one post by Marduk, which I believe is one of the smartest sentences one can make in discussions like these:

I don’t know what that sentence means.

That wasn't directly related to this conversation nor really an indication of lack of understanding in that case, but it makes a good point anyway. It's way too common that people try to avoid asking "stupid" questions and just assume something makes sense since it looks complicated and smart and others don't make questions. It's not at all uncommon that the question turns up to be the smart one and reveals that complicated stuff wasn't.

So, let's ask some stupid questions about the above piece and try to make some understandable simplified answers to the best of my understanding. Here's a number of them in a Q&A form:

Q: What is a waveguide?
A: Take some hollow (non-transparent, such as metal) tube and look through it. That's your waveguide. It guides the electromagnetic waves to move in one dimension by restricting the other dimensions. It would work similarly with waves of water for instance. You can make a different type of waveguide (planar or slab waveguide) by stacking a couple of metal sheets for example and leaving some gap between. Now the light, water or other waves can move in two dimensions while being restricted in one. That's the sort of waveguide we are talking about now. It also happens to be one that has dimensions that just barely let waves of certain length pass through.

Q: So the waves need empty space/air to travel?
A: Not necessarily. Turns out, in this case, they can travel through the bismuth layers that are sandwitched between magnesium layers. Bismuth is a semimetal that can be treated so that it forms an ordered crystalline structure that let's suitable electromagnetic waves to pass through in one direction (as if it was just air).

Q: What's a terahertz wave?
A: It's just one frequency range (also known as submillimeter radiation, which is more descriptive) of electromagnetic waves between the wavelengths of microwaves and infrared light. It just happens to be that the materials and dimensions in question here happen to work well with a part of that range.

Q: So if that piece of supposed alien metal exhibits a negative refractive index and works as a waveguide for terahertz waves, what would it do?
A: Pass those waves through the bismuth layers freely.

Q: That's it?
A: Yep, you can read the details from this research that Puthoff was clearly referring to:
https://arxiv.org/pdf/physics/0505024.pdf
https://arxiv.org/pdf/physics/0405077.pdf
Non-magnetic System with Negative Index of Refraction for Terahertz Application - IEEE Conference Publication

Q: So what does that have to do with anti-gravity?
A: Nothing, and those researchers certainly don't make any such claims, but's let's continue anyway.

Q: What's a negative refractive index material?
A: It refers to a material that bends the light (or other waves) in reverse direction from what you would expect, like that on the right here:
https://media.nature.com/full/nature-assets/nature/journal/v455/n7211/images/455299a-f1.2.jpg
It's also known as backward-wave media.

Q: What's a backward-wave then?
A: Take a look at this (the bottom part of that video):

It shows waves going from left to right, and then highlights with dashed lines how groups of them (wave packets) form shapes that seem to travel to the opposite direction. The speed of those individual short waves is called phase velocity, and the speed of those groups/packets/shapes is called group velocity, and as you can see, they can be different and even opposite.

In a typical backwards wave media like that waveguide in question the phase velocity is negative and the group velocity is positive. So if you hit it with electromagnetic waves (from the left), those waves act like this:

So the wave looks like it goes backwards against the direction it came from, but if you look at those groups/packets/shapes (the higher parts in this short clip), they still go from left to right, which essentially is the direction of energy and information.

Q: So what happens when a wave moves from "normal" media (like air) to a negative refractive index material (like that waveguide)?
A: This:

In that case the wave slows down and seems to act backwards, but you can see that the overall shape (and hence energy and information) still progresses to the same direction.

Q: So what does that have to do with anti-gravity?
A: Nothing, the most interesting applications are those that actually make sense in connection to how electromagnetic waves (including light) behaves, like in antennas and superlenses:
Superlens - Wikipedia

Q: Could such metamaterials have something else to do with UFOs?
A: Yes, as such materials can be used also to wrap electromagnetic waves around objects, resulting an invisibility cloak, both visually and against radar, depending on the applicable wavelengths. The Nimitz case for example possibly showed both types of (at least partial) cloaking.

Q: What's a negative Poynting vector?
A: Let's start with that vector part. It's typically visualized as an arrow, which has direction and length. In this case those signify the direction and density/intensity of energy transfer through the material (energy flux) at some location. They are like the arrows here:
Poynting vector - Wikipedia

Q: So they change all the time?
A: Yes when they are used to represent instantaneous energy flow, as they are defined as being perpendicular to both the electric and magnetic fields (so a cross product of those), which in turn are perpendicular to each other and oscillating, like this:

Because of that it's more useful to talk about time-averaged Poynting vectors, which means taking their average direction and magnitude over some longer time interval, which reveals the overall direction of energy flow.

Q: What does it mean if they are negative?
A: So, what is a negative vector? Can you draw a negative arrow? It has to mean it's reversed/opposite, right? Opposite to what? Let's look at this video again:

In that case, when the waves coming from the left hit the edge of the negative index material at the center of the screen, they look like they go backwards (negative phase velocity) but the group as a whole still goes forward (positive group velocity). As was mentioned above, that means the energy still flows to the right, into the material, which also means that's the direction of the Poynting vector. It's opposite to the phase velocity, but that doesn't make it negative. It would basically need to be against the normal flow of energy, and there are cases where it can, at least locally and temporarily in some parts, but here it's not. It's positive, and it would be positive in other velocity combinations as well:

Here we report results of corresponding experiments on negative–refractive-index materials. These highly unusual materials have only recently become available , with the optical regime becoming accessible only within the past year. The phase velocity in these materials is negative. We directly measured both group and phase velocity by propagating a femtosecond laser pulse through a negative-index metamaterial and then time resolving the transmitted pulse using interferometry. These experiments are the negative-index counterpart of the above experiments for positive-index materials, where vphase>0 and vgroup<0. We found conditions where vphase<0 and vgroup<0, and others where vphase<0 and vgroup>0. Together with the usual situation of vphase>0 and vgroup>0, all four sign combinations have now been observed in direct experiments. For all four sign combinations, the Poynting vector is positive, i.e., along the forward direction.
...
We have shown in direct pulse propagation experiments on negative-index metamaterials that the phase velocity can be negative. Furthermore, contrary to common intuition, the group velocity can also be negative simultaneously. For other spectral positions, we find negative phase velocity and positive group velocity. For all sign combinations of phase and group velocity in effective metamaterials, the Poynting vector is positive — otherwise no signal would be transmitted through the sample.

Simultaneous Negative Phase and Group Velocity of Light in a Metamaterial

Q: So what does that have to do with anti-gravity?
A: Nothing. That was the point.

Since Marduk already told how his theoretical physicist friends also told how "you can't engineer the tensor at all in ways that you (Thomas) describe", it's probably unnecessary to go into those parts anymore, especially since the rest of it is already based on invalid assumptions.

It's probably worth pointing out however that if one tries to do simplistic calculations on negative-index materials, in some cases those can seem to give unphysical results like faster than light travel, break of causality, and negative energies. There are a whole lot details that need to be taken into account, and some equations do not work unmodified with such materials. There are some edge cases that may be interpreted as for example some temporary localized negative energy values as the progressing wave for example sort of borrows and gives back energy to the material. But in any case the law of conservation of energy still applies. Positive energy doesn't magically become negative and so on.

 

[marduk]

Transistor doesn't exist in universe, not even steel or bronze exist in the universe. And list goes on integrated circuits, superconductors and meta-materials.

We are talking here is something mathematically possible, not is it engineerable.

Mathematics discovered anti-matter. Anti-mater was so far out that it didn't exist even in science fiction.

And if you want time crystals, were recently invented by Frank Wilchek from pure mathematical solution. If Wilcheck was not a Nobel laureate and didn't have such a strong brand, I am sure that a ton of negativists would just berry him alive.

If negative mass is supported with a good solid mathematical deviation, it will be made in a physical form, even if we need to wait 100-500 years and even if we need to assemble it molecule by molecule.

But you are sidetracking the whole thread. This thread is to discuss metric engineering in "near horizon" of modern science. Like, the next big thing format. If you know of some good science papers on this subject please contribute. If you don't, why don't you start another thread and discuss your own points.

You are ruining it for everybody else who wants to get more information on this subject.

I thought the purpose of the Paracast was to separate the signal from the noise?

PS math didn’t discover antimatter. Math can’t discover anything that isn’t discoverable mathematically. Godel had some interesting things to say about that.

PPS I really like a lot of the hypothetical lines of inquiry here, including yours any Thomas’. I’m actually on your side. I’m challenging the soft spots in your logic, the ad hominem attacks, and the jubilant sense that someone’s about to cook this stuff up like the basic problems have been solved. Use skeptical people to refine your arguement - if you want the academic community to pay attention to you especially.

 

[Realm]

If negative mass is supported with a good solid mathematical deviation

It isn't.

 

[marduk]

This is starting to feel more like a religious or political debate than a rational or scientific one.

 

[marduk]

It isn't.

Here’s a good, solid, plain-speak article from one of the leading physicists in the area actually doing the basic science.

http://physicstoday.scitation.org/do/10.1063/PT.6.3.20170524a/full/

I hate to add to the link spam but this one is good and insightful. What he’s basically saying is that some people say we’ve already created it therefore it’s possible, some people are saying you haven’t and therefore maybe it’s not, and he’s doing the science and he says “maybe.”

Maybe is good. Maybe is rational. Maybe is let’s think about it. Maybe is let’s test it. Maybe is let’s speculate about what we’d expect to see if it’s possible.

But maybe is not let’s start building a warp 1 capable ship because we’ve got the math worked out.

 

[DROBNJAK]

I haven't really been eager to go into the details of those metamaterials, as there's really no point, since there's not even a single credible source for the sort of ideas that have been discussed here. But since they in themselves are interesting, let's see if we can actually turn this conversation from this technobabble below into something that could be understandable and useful for wider audiences:

Thanks for the great explanation. This is kind of arguments that we need. Now I have motivation to invest more time into learning more about what you and @Thomas R Morrison proposed and getting closer to the full picture.

As you said Tera-hertz radiation is between microwaves and infra red. That's still very low energy region on astrophysics scale. What I found during my digging is that a single Gamma ray can contain about 1,000 time more mass-energy, in electron volts, than any nucleon, like proton or neutron. So if @Thomas R Morrison is right, and negative Poynting vector can be made, than we have negative mass that can easily match mass-energy of normal matter. Obviously Gama rays are so energetic that they would tear apart most known materials.

I would like to appeal to you to turn to the max your creativity and the inner devil's advocate and temporarily switch to Thomase's side. Just in case if there is some accidentally overseen possibility that negative Poynting vector is mathematically valid.

 

[marduk]

Thanks for the great explanation. This is kind of arguments that we need. Now I have motivation to invest more time into learning more about what you and @Thomas R Morrison proposed and getting closer to the full picture.

As you said Tera-hertz radiation is between microwaves and infra red. That's still very low energy region on astrophysics scale. What I found during my digging is that a single Gamma ray can contain about 1,000 time more mass-energy, in electron volts, than any nucleon, like proton or neutron. So if @Thomas R Morrison is right, and negative Poynting vector can be made, than we have negative mass that can easily match mass-energy of normal matter. Obviously Gama rays are so energetic that they would tear apart most known materials.

I would like to appeal to you to turn to the max your creativity and the inner devil's advocate and temporarily switch to Thomase's side. Just in case if there is some accidentally overseen possibility that negative Poynting vector is mathematically valid.

That’s a very reasonable ask.

 

[Thomas R Morrison]

Whoa - six new posts in this thread while I was replying to the last couple. I'll have to catch up later.

Lol, you know that's not what I'm doing at all.

Actually no I didn’t know that, or I wouldn’t have asked. Marduk – you object to every idea that hasn’t been experimentally proven yet – you know that, right? If you want to talk about beliefs and religion: materialism is your religion. Or at least it sure seemed to be, until you just said that GR is solid. I honestly wonder if you talked about gravity waves the same way that you talk about metric engineering today, before they were detected.

GR isn't a belief system because it's been proven. Unlike string theory which probably should go on the garbage heap, even though it's very interesting and satisfying, mathematically. Why do you think the scientific community just spent more money proving gravity waves exist? Most physicists - theoretical and experimental - assumed they existed. But they still checked because reality might surprise us.

You sound like me here – it’s really refreshing to hear you support a theory. At some point we’ll have to replace GR with a GUT to handle quantum regimes, so I’d prefer to say “established/valid/etc” rather than “proven,” but it’s nice to agree about this.

I'm not unwilling to recognize validity of things that have been tested. Or even that things that have yet to be tested might be real. I'm unwilling to recognize the validity of things that are untestable.

We disagree about the definition of “untestable.” I define that term as “fundamentally untestable in principle,” like trying to simultaneously determine the position and momentum of a particle more precisely than the Heisenberg uncertainty principle permits. You seem to define it as “anything that can’t be tested today,” which I think is kinda nutty, honestly. Lots of predictions of GR were untestable, until they weren’t, and then shortly after they were proven. Einstein couldn’t foresee the detection of gravity waves because they’re so weak, but a century later here we are. The Lense-Thirring effect was untestable for many decades, now that’s proven. Everything’s untestable until it’s not. The modulation of mass using the stress-energy tensor is fully accepted by relativists – the technology to test it just hasn’t arrived yet. But it will.

You're essentially claiming much of this is resolved, and an engineering problem. I'm saying the basic science has yet to be done. You have a bad habit of tying interesting frameworks together in novel ways - which is great - and then basically saying the problem is solved... when they unfortunately require a lot of unobtanium to make work.

This is what surprises me – we’ve been over this and you still think that it takes some magical form of matter to make it work: it doesn’t. This is a question of magnitude, not principle. An object under pressure has a higher mass than the same object not under pressure – that’s GR and nobody disputes it. We just haven’t been able to directly measure it because we haven’t been able to produce enough pressure to measure the change in mass yet - our instruments are simply insufficiently sensitive. Similarly, a drop of soapy water has more mass than that same drop of soapy water made into a soap bubble, because the tension of the soap bubble contributes a negative component (via negative pressure) in the stress-energy tensor. It’s a super tiny effect in a soap bubble, but it’s there. It’s only a matter of time before we prove it experimentally. That could be decades or centuries away, I have no idea, but that’s an intrinsic prediction of GR. So yeah, it’s an engineering and materials science problem, not an intrinsically untestable effect. I don’t understand why you can’t see that, if you say that GR is proven.

The AC drive (I'm tired of trying to spell it at this point) isn't an engineering problem. It's a basic science problem. I hope we crack it.

The Alcubierre drive concept was a basic science problem when we thought that exotic matter was required for negative mass. Paranjape’s papers showed that it’s not required – matter under tension can produce the same effect. So it’ll take more theoretical development before we can engineer an experiment to test it out, but we’ll get there. There are probably some geniuses out there right now trying to figure out a viable path forward, and sooner or later, somebody will. Because it’s no longer a fundamental physics problem. And I recently noticed some very interesting papers about negative energy states in QFT which might yield a short-cut. We’ll see.

You assume too much, Thomas. I hope it won't be your undoing. But it is a weakness in your logic.

All that I’m assuming is A.) GR is essentially correct and the stress-energy tensors are valid and B.) Sooner or later we’ll exploit them to an extent sufficient to be tested experimentally, and then eventually we'll apply these effects technologically. That’s all.

I don’t know why you can’t see this - GR is just a physics theory, like any other physics theory: it has technological applications. It’s only a matter of time and work and technological progress before “applied general relativity” is a college course like “engineering topological insulators.”

Already done. But you know that already, right? You know that you'll just say that they 'don't get it' or are 'talking out their ass' or whatever.

Good, no, and no. I love discussing this kind of thing with professional physicists, because they understand the significance of the literature that’s already out there, and they’re usually as excited as I am about seeing the roads forward. It’s the people who don’t understand the science who take a draconian stance against every new idea that hasn’t been experimentally proven yet, because 1.) that's always the safest position: "deny everything that remains unproven," and 2.) they mistake “skepticism” for “negativity” and “derision,” and they think that “real scientists” are married to the limits of present-day science and technology. But in reality, the more qualified a physicist is, the more excited they are about pending developments – because that’s where the action is, and that’s the stuff they live for. Like Feynman getting all excited about the prospect of a nanotechnology to encode the entire Library of Congress into the head of a pin - the best scientists are the biggest fanboy geeks, they just mastered the science so they could lead the way.

Basic science has yet to be done. Every single one I've talked to say the AC drive likely won't work in reality. Every one I've talked to say that much of the things you point as done are in fact not done, not repeatable, not tested or proven, and some aren't testable at all.

Well there’s the problem: the 1994 warp drive paper by Alcubierre is only one very exotic approach to gravitational field propulsion, and in it he postulated negative matter, which probably doesn’t even exist.

But it doesn’t take either one of those two things to produce gravitational field propulsion, we now know. This field hasn’t been standing still for the last 24 years. And Robert Forward’s paper about this (Negative Matter Propulsion, 1990) actually predated Alcubierre’s paper. There’s also an intermediary strategy that’s very exciting: if we can produce a negative effective mass (negative inertial mass with only an insignificant gravitational field) using positive matter, as Paranjape demonstrated theoretically, then we can electrostatically couple that to positive matter to produce a self-accelerating device (in fact, Forward even showed that a frickn' spring attached between them would to the trick). And even when we develop the idea further, so we can engineer a 100% gravitationally coupling system that can accelerate all of the matter within a device uniformly – true gravitational field propulsion – we won’t need to produce a spherical warp bubble around the craft as Alcubierre described. That was just one conceptually simple but physically impractical (and probably impracticable) approach to demonstrate the theoretical validity of the concept within GR.

So I would never broach this subject by asking “hey, what do you make of the Alcubierre drive?” Because that’s a very thorny and iffy proposition. I’d probably start by bringing up Robert L. Forward’s 1990 paper, and follow it up with Paranjape’s papers from 2013 and 2014. Because that stuff focuses on the key principles, without all of the crazy contextual and field configuration hurdles that don’t matter anyway.

The ones I've talked to say that you can't engineer the tensor at all in ways that you describe. I'm not going to get in a he said-you said debate with you.

Yeah I kinda shudder to think how you might’ve phrased the question – if they think we’re talking about the Alcubierre drive, then there are a number of reasons they’d be dismissive, and at least two good reasons to write it off completely.

But if you asked the right question: “can the stress-energy tensors produce positive and negative contributions to the rest mass of a body?” then they’d say “of course,” because that’s not even a debate. How to do it for practical applications, and the magnitude of those effects – that’s an interesting subject for debate. But the principle? Nobody who’s studied GR would have an objection to that – it’s a fundamental feature of the theory.

Put the papers down and describe how you'd engineer the tensor to produce the effects you want in a material that exists in the universe. Using energetic states known to exist in the universe. And what exactly you predict it would do.

And then build it and test it, because now you have a science problem you can solve with engineering.

You’re an impatient man, marduk. This isn’t something that you can just sketch out on a napkin and hand off to an engineer. But I think that Paranjape is on the right track with his idea about a bubble of positive matter under high tension. Bubble nuclei might be a good place to start, because then you’re dealing with the nuclear strong force – and the nuclear strong force is the ideal candidate for producing extremely high tensions because in some scenarios like nucleons, it actually gets stronger the harder you pull quarks apart (asymptotic freedom). But I’m also intrigued with topological insulators and metamaterials, and the magnetostrictive and electrostrictive properties that some into play at boundaries within layered materials (which only recently came to light with recent studies into metamaterials) – with very thin layers undergoing powerful tensions induced by radiation, you just might be able to “constrict” matter powerfully enough to produce a detectable drop in rest mass. Or it might be even better to just create a stack capacitor using dozens of very thin sheets of conductor sandwiched between a really good lightweight dielectric, to produce very high tensions in the insulator material. But you’d need a dielectric with a very high breakdown voltage, and that could be a significant materials engineering problem – the recent development of topological insulators looks like a promising direction for that kind of work.

I never once said that I don't believe in QM. I said that the LHC was a science problem that was solvable by engineering. This is not a belief problem, man!

Are you sure that it’s not a disbelief problem, then? ;

I see this as a science problem that’s solvable by engineering as well – it’s just further out, because we have to develop new techniques and materials to get there. But with the positive energy theorem out of the way now (Parajape, 2013) and the exotic matter problem out of the way (Parajape, 2014), the fundamental theoretical obstacles have been swept aside. So now we can focus on the real-world physics problems.

Look. I’m seeing this from the bird’s eye view. And here’s how it’s going:

- when I was growing up and going to school, everybody said that gravitational field propulsion was untenable even in theory, and only loons and crackpots talked about gravitational repulsion aka antigravity. And it appears that this viewpoint was devised and promoted by government agencies like the CIA to quell public interest in ufos (probably because they represent an unidentified national security risk that our military is totally powerless to defend against).

- but I later learned that in 1963 Robert L. Forward had described a conceptually viable gravitational dipole generator that’s fully consistent with general relativity - the entire academic physics community had completely ignored this discovery and it got buried so deeply that even after years of maniacally ravaging the university library system for this idea, I wasn’t able to find it until the advent of the internet.

- and in 1990 he published his paper Negative Matter Propulsion, which compiled previous findings by Bondi and others, and illustrated that gravitational field propulsion is at least a theoretically viable concept.

- then in 1994 Miguel Alcubierre published his warp drive paper that forced the theoretical community to finally sit up and take notice, because his metric proved that the idea of gravitational field propulsion is at least fully consistent with GR, even though it’s a tricky design, and he postulated exotic matter because we didn’t know yet that positive matter can exhibit a negative effective mass within GR.

- mainstream academicians went berserk about this – they’d been ridiculing the idea of negative gravitation for decades, mostly as a way to shit on ufo enthusiasts, and now suddenly all these people were proclaiming victory. So they parried with patronizing dismissals about the unphysicality of negative matter, and the inviolability of the positive energy theorem, and the unwashed masses quieted down for a short while.

- suddenly things took a drastic turn in 1998 when astronomers discovered a repulsive gravitational effect accelerating the galaxy clusters apart, and the dewy-eyed dreamers of the world (rightly) proclaimed that antigravity was now an observed physical reality. So the mainstreamers dubbed it “dark energy” to obscure the physical reality of antigravity by making everybody wonder about the mystery behind it, rather than the effect itself. That kinda worked, and it gave the negativists an out: “we don’t know what dark energy is, but it seems to be a ubiquitous isotopic scalar field pervading spacetime itself, so you can’t have it.”

- but by this time, in the background, cosmologists had already proven that the only way to make the Big Bang model work, was Alan Guth’s idea about cosmic inflation – an early geometric expansion of spacetime that smoothed out the cosmic microwave background radiation to yield the nearly perfectly uniform temperature that we see. This was a huge clue in favor of antigravity: the early universe should’ve collapsed instantly under its own gravitation, but instead, it blew up into the universe that we observe – exactly as one would expect with a powerful antigravitational field. Before anyone really noticed this fact, they ascribed this effect to a hypothetical particle that’s not in the Standard Model and called it “the inflaton.” Nobody had any idea wtf they were talking about (and nobody knows, even now) but it only seemed to pertain to the exotic and imponderable first instants after the Big Bang, so it stuck, and everybody shrugged their shoulders and walked away from it.

- for about a decade people bickered about “dark energy” and “dark natter” and MoND, and just really enjoyed the Hubble Mission images for awhile. And in the background, lots of theorists started to develop modifications to GR, our theory of gravity – and lots of really fascinating work is going on right now, but it’s all so speculative that nobody knows what to make of it. And particle physicists are still conducting earnest and ambitious projects to detect dark energy or dark matter particles, which probably don’t exist, but seeing people in lab coats running weird experiments makes people feel like we're making progress, so most people are just patiently waiting for some answers.

- then in 2013 and 2014 Parajape published a couple of real zingers: it turns out the positive energy theorem doesn’t apply to our accelerating de Sitter universe, so negative mass solutions in GR are physically permissible after all. Oops. And you don’t need exotic matter to do it – positive matter under tension can get you there, in principle anyway. But these developments haven’t gotten much traction, mostly because Paranjape’s papers are extremely sophisticated, and the people who understand them don’t want to talk about it: “oh god, not the antigravity thing again… shh!... maybe nobody will notice.”

So that’s where we are today. The long-term trajectory of this stuff is undeniable: this is how revolutionary ideas are born, and struggle to mature, and then one day your great-great-grandson is casually reflecting on his poor primitive ancestors who couldn't even leave the planet, as he warps off to build settlements on Arcturus 5 or whatever.

I've seen these things move. And I don't think what you're describing necessarily gets at the problem.

I’m totally open to suggestions. So how do you get low silent hovering without wind or propellant, apparently instantaneous accelerations from a dead stop to thousands of miles per hour with no indication of a reaction medium, and acute-angle maneuvers with no signs of slowing or banking at thousands of miles per hour, without some kind of gravitational field propulsion principle that obviates g-forces completely?

 

[Realm]

As you said Tera-hertz radiation is between microwaves and infra red. That's still very low energy region on astrophysics scale. What I found during my digging is that a single Gamma ray can contain about 1,000 time more mass-energy, in electron volts, than any nucleon, like proton or neutron. So if @Thomas R Morrison is right, and negative Poynting vector can be made, than we have negative mass that can easily match mass-energy of normal matter. Obviously Gama rays are so energetic that they would tear apart most known materials.

I would like to appeal to you to turn to the max your creativity and the inner devil's advocate and temporarily switch to Thomase's side. Just in case if there is some accidentally overseen possibility that negative Poynting vector is mathematically valid.

It just doesn't work like that for a multitude of reasons.

First of all, those negative-index materials have that negative refractive index only for some frequency range of waves. For that bismuth waveguide it happens to be that specific range of terahertz waves. Outside of that it's just like normal matter. So if you for example shine a flashlight towards it, the light doesn't make it through, unlike those terahertz waves. Nothing interesting happens. Gamma rays are just way out of that range. If you have more energy, you may destroy that material, but otherwise it doesn't help.

I'm not saying it actually works quite like this, but I think you can visualize the situation as follows: Imagine you have a multistorey parking garage, which has no walls but solid floors and ceilings (like those magnesium walls of that waveguide) and between them there's empty space except for a regular structure of support columns (like the internal crystalline structure of that bismuth). Now imagine you try to send a wave to go through it, and the wave looks like this blue one here, so it's sort of flat and goes from left to right:

If you want to make that to go through the entire floor to the other side without hitting anything, it has to be of specific shape, that is, the wave length has to be correct, otherwise it will hit one of the columns sooner or later. But if the length is about the same as the distance of those columns, it might just neatly slither around them in a well defined manner. The energy of that wave doesn't really matter, except that a high energy one might destroy the columns it hits.

As for negative Poynting vector, the paper I quoted above already indicated what that would mean:

For all sign combinations of phase and group velocity in effective metamaterials, the Poynting vector is positive — otherwise no signal would be transmitted through the sample.

So again, it just wouldn't work. Remember that the Poynting vector signifies the direction of energy. So a negative one would go to the opposite direction. In that case the wave just wouldn't go into the material, it would be like hitting a solid wall. As I also mentioned, it can be negative in some cases, which don't even need metamaterials, but again, it just means the direction of energy is reversed, not that it would magically create some sort of negative anti-gravity energy.

Also remember that even if you have energy flow out of some piece of material, it doesn't make it an anti-gravity device. You can drain a fully charged battery empty of energy, and in principle it gets just a tiny bit lighter in that process, but nobody calls that anti-gravity. Taking something out is not the same thing as adding something negative.

Which brings us back nicely to the questions about negative mass and runaway motion, and why the math or tests of general relativity do not tell if those are real.

Imagine you have an empty basket and a bunch of apples next to it on a table. Then you have this fantastic well tested equation, according to which you should make chances to the apple content of that basket:

A+B=C

If I ask you to make the basket contain 5 apples, you can do that according to the equation, 0+5=5 by picking up and dropping those 5 apples there. Now make it contain zero apples again according to that equation. Can you do it? In principle the equation works:

5+(-5)=0

So you pick up 5 negative apples from the table and drop them into the basket... Wait, what do those taste like? So the math works, but that doesn't mean negative apples exist. Do the rules allow you to take the existing apples out from the basket instead? I didn't mention that, so you can't know. The situation with negative mass is pretty much the same as those negative apples. Maybe they exist somewhere, even though we haven't seen any, but the math and our current knowledge doesn't tell that.

The situation with runaway motion is somewhat similar. Say you have a sports car that weights 1000kg, and you want to make it lighter so that it would accelerate better. How do you do it? How about attaching a trailer to it, one that weights -1000kg? Now, do you have a car that weights 1000-1000, that is nothing, as long as the trailer is attached, or did you just cheat on math? I believe most would say the latter. That's basically the trick that has been made with that runaway motion to the equations to cancel out the mass and make those terms zero, which evades the usual rules. It's no wonder if most consider that to be unphysical.

 

[Realm]

Here’s a good, solid, plain-speak article from one of the leading physicists in the area actually doing the basic science.

That physicist is Paranjape, who has been referenced here a lot lately. Here's a repeat of some of the comments I made about his idea on the first page of this thread:

Anti-gravity/negative mass doesn't seem to have that many voices of strong support, but rather a small number of researchers, who seem to give it higher probability than most. As we have already discussed, Paranjape is one of them, and to me his research looks more like resuscitating a troubled theoretical possibility. And even he talks about it as a possibility and primarily in the context of early universe, rest being even more iffy.

What's more, not everyone accepts that as negative mass solution at all. Sabine Hossenfelder is another reputable theoretical physicist and here's what she said about that research at the time:

However, it is somewhat misleading to call the solution that they find a negative mass solution. The cosmological constant makes a contribution to the effective mass term in what you can plausibly interpret as the gravitational potential. Taken together both, the effective mass in the potential is positive in the region where this solution applies. The local mass (density) is also positive by assumption. (You see this most easily by looking at fig 1 in the paper.)

Selling this as a negative mass solution is like one of these ads that say you’ll save 10$ if you spend at least $100 – in the end your expenses are always positive. The negative mass in their solution corresponds to the supposed savings that you make. You never really get to see them. What really matters are the total expenses. And these are always positive. There are thus no negative mass particles in this scenario whatsoever. Further, the cosmological constant is necessary for these solutions to exist, so you cannot employ them to replace the cosmological constant.

It also must be added that showing the existence of a certain solution to Einstein’s field equations is one thing, showing that they have a reasonable chance to actually be realized in Nature is an entirely different thing. For this you have to come up with a mechanism to create them and you also have to show that they are stable. Neither point is addressed in the paper.
...
In summary, I think it’s an interesting work, but so far it’s an entirely theoretical construct and its relevance for the description of cosmological dynamics is entirely unclear. There are no negative mass particles in this paper in any sensible interpretation of this term.

Backreaction: Negative Mass in General Relativity?

But in general I support what you said.

 

[marduk]

Whoa - six new posts in this thread while I was replying to the last couple. I'll have to catch up later.


Actually no I didn’t know that, or I wouldn’t have asked. Marduk – you object to every idea that hasn’t been experimentally proven yet – you know that, right? If you want to talk about beliefs and religion: materialism is your religion. Or at least it sure seemed to be, until you just said that GR is solid. I honestly wonder if you talked about gravity waves the same way that you talk about metric engineering today, before they were detected.

Not the point of this thread, but materialism isn't religion, because it requires no faith. Unless you count a total lack of faith as faith.

You can't prove that there's nothing but the physical universe. My assertion is that's all there is because it's all you can prove.

Until gravity waves were detected, I would have said that there is evidence to strongly suspect they exist, but they were unproven. Because up until they were detected, they were unproven. Do you not remember all the hulaballo around it when they turned on LIGO and it didn't find anything for a while? People were freaking out, because they may have had to re-think GR.

You sound like me here – it’s really refreshing to hear you support a theory. At some point we’ll have to replace GR with a GUT to handle quantum regimes, so I’d prefer to say “established/valid/etc” rather than “proven,” but it’s nice to agree about this.

K. With you so far.

We disagree about the definition of “untestable.” I define that term as “fundamentally untestable in principle,” like trying to simultaneously determine the position and momentum of a particle more precisely than the Heisenberg uncertainty principle permits. You seem to define it as “anything that can’t be tested today,” which I think is kinda nutty, honestly. Lots of predictions of GR were untestable, until they weren’t, and then shortly after they were proven. Einstein couldn’t foresee the detection of gravity waves because they’re so weak, but a century later here we are. The Lense-Thirring effect was untestable for many decades, now that’s proven. Everything’s untestable until it’s not. The modulation of mass using the stress-energy tensor is fully accepted by relativists – the technology to test it just hasn’t arrived yet. But it will.

Again, patiently, this is not what I'm saying. There is a classification of stuff that is currently untestable. That set of things contains items like 'do aliens come from Zeta Reticuli?' and 'P=NP' and the 'Riemann Hypothesis.' These are things that can in theory be tested, but we just don't currently know how.

And that is not at all what I'm talking about.

There is another set of things like the 'Uncertainty Principle' and 'String Theory' and 'Loop Quantum Gravity' and 'What's up with Trump's hair?' which may be fundamentally untestable.

They are untestable for fundamental reasons. I would argue that String Theory is in fact bad science for a simple reason: you can't really test it. It's very elegant, but confusing, and so pliable that you can find a derivation that solves for all possible outcomes. Therefore, it's untestable. As cool as it is.

You're a math guy like me, I think. It's like the difference between a countably infinite set and an uncountably infinite set. It may seem like the same thing but it's totally not.

My argument is that for things that require states of matter which may or may not exist, or states of energy that may or may not exist, or conditions that may or may not be possible to configure... these things are fundamentally untestable until you can figure out a way to create the matter or energy or configuration.

For negative matter, I've referenced an article where a leading physicist - who seems to really think it may exist - can't prove it. But he thinks he has evidence to think it may exist which may allow for all kinds of cool things. And he's trying to either find a way to make it, or find it in the universe. Which I think is awesome.

But even he doesn't run around saying he's proven anything. He says maybe. He says it solves certain problems. That maybe they could make it work. And he's going to go try, even though Hawking himself said it's not gonna work. This is a guy doing the basic science, who is hoping it exists, and even he isn't saying it's a done deal. Until he can make it work, then the problems it would solve are untestable. This is an A-> B -> C :: A->C problem. Without B you ain't getting to C, with a side order of A can’t be true then, either.

My problem with what you are saying, in the simplest possible way, is that you're behaving as if it's a done deal. It's not a done deal.

If you want to go around saying "I hope negative states of matter exist, and I'm encouraged because of this evidence {X,Y,Z} because then it would mean that we have antigravity and free energy and we can finally meet whatever it is in our skies on equal footing!" then I'd be saying f'ing a, man. How can we help this guy?

 

[marduk]

This is what surprises me – we’ve been over this and you still think that it takes some magical form of matter to make it work: it doesn’t. This is a question of magnitude, not principle. An object under pressure has a higher mass than the same object not under pressure – that’s GR and nobody disputes it. We just haven’t been able to directly measure it because we haven’t been able to produce enough pressure to measure the change in mass yet - our instruments are simply insufficiently sensitive. Similarly, a drop of soapy water has more mass than that same drop of soapy water made into a soap bubble, because the tension of the soap bubble contributes a negative component (via negative pressure) in the stress-energy tensor. It’s a super tiny effect in a soap bubble, but it’s there. It’s only a matter of time before we prove it experimentally. That could be decades or centuries away, I have no idea, but that’s an intrinsic prediction of GR. So yeah, it’s an engineering and materials science problem, not an intrinsically untestable effect. I don’t understand why you can’t see that, if you say that GR is proven.

Uh, the dude himself references that in the article and says 'maybe.' With a heaping helping of 'need to do more basic science on this.'

The Alcubierre drive concept was a basic science problem when we thought that exotic matter was required for negative mass. Paranjape’s papers showed that it’s not required – matter under tension can produce the same effect. So it’ll take more theoretical development before we can engineer an experiment to test it out, but we’ll get there. There are probably some geniuses out there right now trying to figure out a viable path forward, and sooner or later, somebody will. Because it’s no longer a fundamental physics problem. And I recently noticed some very interesting papers about negative energy states in QFT which might yield a short-cut. We’ll see.

The difference between you and me is you think the AC will work. I hope it will work.

I think we will somehow crack the ability to go to other planets in a big way, because life seems to work by colonizing whatever it can to occupy the niches available. So if we don't blow ourselves away or just die, I think we'll get there. It may be FTL using something like an AC drive. It may be something totally different. I don't know.

All that I’m assuming is A.) GR is essentially correct and the stress-energy tensors are valid and B.) Sooner or later we’ll exploit them to an extent sufficient to be tested experimentally, and then eventually we'll apply these effects technologically. That’s all.

I think we just agreed!

I don’t know why you can’t see this - GR is just a physics theory, like any other physics theory: it has technological applications. It’s only a matter of time and work and technological progress before “applied general relativity” is a college course like “engineering topological insulators.”

Cough, cough, a testable theory.

Paranjape himself says he doesn't know how to test it, or that we'll ever be able to. But it's worthwhile trying because there is some theoretical evidence it may be there and it would be super cool.

Good, no, and no. I love discussing this kind of thing with professional physicists, because they understand the significance of the literature that’s already out there, and they’re usually as excited as I am about seeing the roads forward. It’s the people who don’t understand the science who take a draconian stance against every new idea that hasn’t been experimentally proven yet, because 1.) that's always the safest position: "deny everything that remains unproven," and 2.) they mistake “skepticism” for “negativity” and “derision,” and they think that “real scientists” are married to the limits of present-day science and technology. But in reality, the more qualified a physicist is, the more excited they are about pending developments – because that’s where the action is, and that’s the stuff they live for. Like Feynman getting all excited about the prospect of a nanotechnology to encode the entire Library of Congress into the head of a pin - the best scientists are the biggest fanboy geeks, they just mastered the science so they could lead the way.

I come from the school that good science is always skeptical and personal bias is a giant problem. Which is why you have to rely on the scientific method at all times.

I want you to be right. I want you to be listened to. To get at those things, you need someone criticizing your efforts in an honest way. Otherwise, others are just going to throw it in the pseudoscience bucket.

Well there’s the problem: the 1994 warp drive paper by Alcubierre is only one very exotic approach to gravitational field propulsion, and in it he postulated negative matter, which probably doesn’t even exist.

But it doesn’t take either one of those two things to produce gravitational field propulsion, we now know.

And here's where I go nuts. Those three little words. 'We now know.'

We don't know. We have reason to suspect. We have some evidence for. We don't know it will do what you want it to do.

That is my basic criticism of your argument right there, in those three little words.

 

[marduk]

It just doesn't work like that for a multitude of reasons.

First of all, those negative-index materials have that negative refractive index only for some frequency range of waves. For that bismuth waveguide it happens to be that specific range of terahertz waves. Outside of that it's just like normal matter. So if you for example shine a flashlight towards it, the light doesn't make it through, unlike those terahertz waves. Nothing interesting happens. Gamma rays are just way out of that range. If you have more energy, you may destroy that material, but otherwise it doesn't help.

I'm not saying it actually works quite like this, but I think you can visualize the situation as follows: Imagine you have a multistorey parking garage, which has no walls but solid floors and ceilings (like those magnesium walls of that waveguide) and between them there's empty space except for a regular structure of support columns (like the internal crystalline structure of that bismuth). Now imagine you try to send a wave to go through it, and the wave looks like this blue one here, so it's sort of flat and goes from left to right:

If you want to make that to go through the entire floor to the other side without hitting anything, it has to be of specific shape, that is, the wave length has to be correct, otherwise it will hit one of the columns sooner or later. But if the length is about the same as the distance of those columns, it might just neatly slither around them in a well defined manner. The energy of that wave doesn't really matter, except that a high energy one might destroy the columns it hits.

As for negative Poynting vector, the paper I quoted above already indicated what that would mean:



So again, it just wouldn't work. Remember that the Poynting vector signifies the direction of energy. So a negative one would go to the opposite direction. In that case the wave just wouldn't go into the material, it would be like hitting a solid wall. As I also mentioned, it can be negative in some cases, which don't even need metamaterials, but again, it just means the direction of energy is reversed, not that it would magically create some sort of negative anti-gravity energy.

Also remember that even if you have energy flow out of some piece of material, it doesn't make it an anti-gravity device. You can drain a fully charged battery empty of energy, and in principle it gets just a tiny bit lighter in that process, but nobody calls that anti-gravity. Taking something out is not the same thing as adding something negative.

Which brings us back nicely to the questions about negative mass and runaway motion, and why the math or tests of general relativity do not tell if those are real.

Imagine you have an empty basket and a bunch of apples next to it on a table. Then you have this fantastic well tested equation, according to which you should make chances to the apple content of that basket:

A+B=C

If I ask you to make the basket contain 5 apples, you can do that according to the equation, 0+5=5 by picking up and dropping those 5 apples there. Now make it contain zero apples again according to that equation. Can you do it? In principle the equation works:

5+(-5)=0

So you pick up 5 negative apples from the table and drop them into the basket... Wait, what do those taste like? So the math works, but that doesn't mean negative apples exist. Do the rules allow you to take the existing apples out from the basket instead? I didn't mention that, so you can't know. The situation with negative mass is pretty much the same as those negative apples. Maybe they exist somewhere, even though we haven't seen any, but the math and our current knowledge doesn't tell that.

The situation with runaway motion is somewhat similar. Say you have a sports car that weights 1000kg, and you want to make it lighter so that it would accelerate better. How do you do it? How about attaching a trailer to it, one that weights -1000kg? Now, do you have a car that weights 1000-1000, that is nothing, as long as the trailer is attached, or did you just cheat on math? I believe most would say the latter. That's basically the trick that has been made with that runaway motion to the equations to cancel out the mass and make those terms zero, which evades the usual rules. It's no wonder if most consider that to be unphysical.

It's also very interesting that whatshisname references a key insight - and problem - with negative energy.

He says that if you have a 5kg mass and a -5kg mass, the 5kg mass will be attracted to the -5kg mass. The -5kg mass will be repulsed by it.

So the 5kg mass would chase the -5kg mass through the universe if they were in space. For free, for forever, you'd have thrust, these two weights chasing each other until the end of time - or unless they hit something.

Which gets back to my thermodynamics problem, because you just created a perpetual motion device and created energy from nothing.

 

[DROBNJAK]

It's also very interesting that whatshisname references a key insight - and problem - with negative energy.

He says that if you have a 5kg mass and a -5kg mass, the 5kg mass will be attracted to the -5kg mass. The -5kg mass will be repulsed by it.

So the 5kg mass would chase the -5kg mass through the universe if they were in space. For free, for forever, you'd have thrust, these two weights chasing each other until the end of time - or unless they hit something.

Which gets back to my thermodynamics problem, because you just created a perpetual motion device and created energy from nothing.

Apparently, there is no problem with thermodynamics, because they are not actually moving. Negative mass has negative momentum and sum of momentum is zero. Negative mass has negative energy and positive mass has positive energy, so sum is again zero.

Martin Tajmar explains it quite well here @8:54 and onwards:

 

[Thomas R Morrison]

Not the point of this thread, but materialism isn't religion, because it requires no faith. Unless you count a total lack of faith as faith.

I'm just saying that belief and disbelief are two sides of the same coin - you can take either one too far, and proponents of either position often end up defending their belief or disbelief, rather than debating the issues in an unbiased manner. It's best not to plant your flag in either camp, and just impartially let the facts speak for themselves rather than starting with a position and then arguing to defend it. That's the true meaning of skepticism.

You can't prove that there's nothing but the physical universe. My assertion is that's all there is because it's all you can prove.

I like the middle road: "all that we can prove is what we can observe with the senses and measure with physical instruments, but there may also be aspects of the universe that we can't observe with the senses or measure with physical instruments." I think it's good to have some sense of humility and acknowledge that not only may we be missing unseen factors, but we may be missing fundamentally unseeable factors too.

Here's just one example: Dr. Itzhak Bars, one of the most brilliant theoretical physicists in the world (and a professor at my alma mater actually - I used to try to read his superstring papers when I worked at the graduate physics dept., but they were outlandishly sophisticated), has proposed a fascinating theory that describes our universe as 6-dimensional (2 time and 4 space dimensions, all macroscopic), where the laws of physics are constrained by a specific simple gauge symmetry that perfectly produces the illusion (or "shadow") of our 4D universe. So the only way to detect that it's actually a 6D universe, is by discovering unexpected symmetries in a wide variety of seemingly uncorrelated physical phenomena (and conjugate variables like position and momentum), which we do in fact observe. But there's no way to *prove* it, because in his theory the laws of physics perfectly mimic a 4D universe. However, it may be true - we may be embedded in a 6D universe.

Until gravity waves were detected, I would have said that there is evidence to strongly suspect they exist, but they were unproven.

That's exactly where we stand with the stress-energy tensors: GR predicts that they can be manipulated to modulate the rest mass of a body, and we have convincing evidence to suggest that this is true. Here are a couple of quotes from a wonderful little paper that I just found, co-authored by one of my favorite physicists, John Baez:

"We promised to state Einstein’s equation in plain English, but have not done so yet. Here it is:

Given a small ball of freely falling test particles initially at rest with respect to each other, the rate at which it begins to shrink is proportional to its volume times: the energy density at the center of the ball, plus the pressure in the x direction at that point, plus the pressure in the y direction, plus the pressure in the z direction."

and

"There are a number of important situations in which ρ (energy density) does not dominate over P (pressure). In a neutron star, for example, which is held up by the degeneracy pressure of the neutronium it consists of, pressure and energy density contribute comparably to the right-hand side of Einstein’s equation. Moreover, above a mass of about 2 solar masses a nonrotating neutron star will inevitably collapse to form a black hole, thanks in part to the gravitational attraction caused by pressure."
"The Meaning of Einstein’s Equation," John C. Baez and Emory F. Bunn, American Journal of Physics, 2006

There is another set of things like the 'Uncertainty Principle' and 'String Theory' and 'Loop Quantum Gravity' and 'What's up with Trump's hair?' which may be fundamentally untestable.

They are untestable for fundamental reasons.

I'm going to ignore the Uncertainly Principle included in there, because that's one of the most well-proven principles in all of physics and a central pillar of QFT. And I'm also going to ignore the string theory and the LQG, because string theory has already made some predictions (kinda - some of the bazillions of permutations of string theories have offered some weird predictions that didn't pan out, but of course there are so many string theories that it's unfalsifiable, and therefore unscientific, imo). Because I understand what you're trying to say.

I'm just saying that you're wrong. As the previous response demonstrates, we already know that pressure plays a key role in gravitation, or our models of neutron stars and black hole formation wouldn't work. I suppose you could try to argue the point, but good luck with that: astronomers have pretty solid models for neutron stars and they've been observed in binary systems so we know the magnitudes of their gravitational fields, and I think that if we were off by a factor 2, somebody would've noticed a problem. In any case, there's nothing fundamentally untestable about the relationship between the stress-energy tensor and inertial mass, which is what we're talking about here: those components represent real physical phenomena like pressure and the Poynting vector, which we can and do generate at high magnitudes right now, and as time passes, those magnitudes are only getting higher - so sooner or later we'll be able to directly detect their influence on inertial mass in the laboratory. But nevertheless, I think I know what point you're trying to get at here, so we'll circle back to it in the next part below.

My argument is that for things that require states of matter which may or may not exist, or states of energy that may or may not exist, or conditions that may or may not be possible to configure... these things are fundamentally untestable until you can figure out a way to create the matter or energy or configuration.

See - these two phrases are incompatible; "fundamentally untestable" and "until you can figure out a way." Because the whole point of a fundamentally untestable idea, is that it excludes any possibility of figuring out how to test it.

It's true that I'm rather cavalier about the prospect for effective and physically realizable negative mass solutions. And that's really what I think you were getting at before. Modulating rest mass up and down using the stress-energy tensor is not a big deal, and not even a debate. But achieving a *net* negative mass - that is a difficult problem. There are two reasons for this:

1.) For the last 40 years I've endured an army of smarmy know-it-all pricks adamantly and often abusively telling me that gravitational field propulsion is forbidden by the laws of physics, as is repulsive gravity aka negative gravity. And I had to suck it up, because the positive energy theorem was a compelling argument that seemed to indicate, on paper anyway, that they were right (even though my own childhood ufo sighting convinced me otherwise, for reasons we've already discussed). But now Paranjape has demonstrated that the positive energy theorem doesn't apply to our accelerating universe, so now we know that negative effective mass solution are theoretically permitted in our universe after all, according to GR, and we don't need exotic matter to produce them. So I'm just enjoying a moment of small personal vindication, since I can now look back at all of those noisy negativists who insisted that it was "case closed," and tell them all to go suck it. Because in so many different realms of physics, my second reason has been routinely confirmed all across the observable universe:

2.) "Everything not forbidden is compulsory." That's Murray Gell-Mann's totalitarian principle, which was first applied to the realm of particle physics, but in fact appears to be a general principle of scientific progress. If the laws of physics don't forbid something from happening, then we humans have found a way to make it happen - sometimes to a modest extent, but usually in the form of sweeping breakthroughs. So I have tremendous confidence that since negative effective mass solutions have now been shown to be physically permissible in the context of GR, sooner or later, we'll get it done. I suppose that one might say that this is an article of faith: I have genuine faith in the long-term ingenuity of mankind and the scientific process to achieve anything which isn't prohibited by the physical laws of nature. Some may find that naive, but I really don't care, because the whole of human history stands as testament to this well-justified article of faith. Which gives me the freedom to investigate *how* this might be achieved, rather than *if* this might be achieved, and that works for me, because it's fun, and endlessly educational.

For negative matter, I've referenced an article where a leading physicist - who seems to really think it may exist - can't prove it. But he thinks he has evidence to think it may exist which may allow for all kinds of cool things. And he's trying to either find a way to make it, or find it in the universe. Which I think is awesome.

But even he doesn't run around saying he's proven anything. He says maybe. He says it solves certain problems. That maybe they could make it work. And he's going to go try, even though Hawking himself said it's not gonna work. This is a guy doing the basic science, who is hoping it exists, and even he isn't saying it's a done deal. Until he can make it work, then the problems it would solve are untestable. This is an A-> B -> C :: A->C problem. Without B you ain't getting to C, with a side order of A can’t be true then, either.

Yeah we were arguing past each other, I've realized. Attenuating rest mass up and down is basic GR - not a contentious point. We might be able to do this in a lab within our lifetimes - say, reduce the mass of a test body by .1% or something. That would be a big deal experimentally, and get us on the right track, but it wouldn't be an earth-shaking achievement in the larger scheme of things: just another confirmation of GR, and a cool to step on the road of progress. That's the part I'm very confident about. But getting to a *net negative effective mass* - that's going to be a real bitch. Not likely to ever happen in our lifetimes. And I'm actually rather conflicted about this prospect, despite my glib posturing about it. Because as Paranjape briefly mentioned in his article, there's a theorem that says that you can't evolve a body of positive matter into a negative effective mass condition - and that worries me. I'm thinking about contacting Paranjape for a supplemental interview for Physics Frontiers, so we can discuss that point and some other questions that I have about his findings, and tack it on to our upcoming episode about his two papers on this subject. And on the other hand, part of me doesn't believe in this restriction - it seems arbitrary and weird. Consider this - the mass of a body is e/c^2, plus the sum of three pressure terms, also over c^2. So assuming that we can generate a uniform negative pressure in all three directions (which is fine - pressure is uniform in all three axes in many situations), then you could get to zero effective mass by producing the tension equivalent of 1/3 of the energy density. Sure, that's a significant challenge, but far from inconceivable. But why the hell would you be limited to 1/3rd? And even if you were (and 1/3 is a bizarre fraction for a fundamental limit in the first place, but let's accept it for a moment), then why couldn't you use a totally different form of tension, say, a negative Poynting vector term or some other independent mechanism, to push it a little bit further to attain a net negative mass? Such a restriction strikes me as oddly physical. We increase a particle mass-energy to arbitrary magnitudes all the time in particle accelerators, so what's so special about going in the opposite direction at we're barred to exceed the pressure equivalent of 1/3 the energy density? Perhaps it'll make sense once I study the basis of this restriction, but my instincts tell me it's BS, or that we can find a way around it.

So any, no - it's not a given that we can produce a net negative mass condition. But given Paranjape's static solution that demonstrates that positive matter can produce a negative effective mass condition, it seems inevitable that we'll do so, one day. And in any case it's just damn nice to move from "theoretically impossible" to "theoretically possible" - that might not seem like a big deal to you, but after decades pursuing this subject to be rebuked by pretty much everyone, it's a big deal to me. Even if we have to figure out how to generate a positive bubble of matter that is "born" in a high tension net negative effective mass state, and then amplify the magnitude of that state to produce a technologically useful component for a gravitational field propulsion experiment, perhaps centuries hence.

If you want to go around saying "I hope negative states of matter exist, and I'm encouraged because of this evidence {X,Y,Z} because then it would mean that we have antigravity and free energy and we can finally meet whatever it is in our skies on equal footing!" then I'd be saying f'ing a, man. How can we help this guy?

That is what I'm saying. Following Paranjape's work, it looks more promising than ever that we'll be able to produce negative mass solutions someday, and what we already know about the stress-energy tensor points us toward mass reduction, so that's a good start and we should work on that. And meanwhile, we can work on the problems with producing a net negative effective mass state.

The difference between you and me is you think the AC will work. I hope it will work.

I'm confident, but not certain. And as I pointed out with the historical sequence in my last post, the trend of theoretical viability (and even the observational support, if we include the astronomical findings), is clearly in our favor. But I'm not going to break out the champagne until I see the experimental data. And unfortunately, if the time for that arrives, it'll probably be when our great-great-grandchildren, or their great-great-grandchildren, are walking around oblivious to our archaic debates about this subject.

I think we will somehow crack the ability to go to other planets in a big way, because life seems to work by colonizing whatever it can to occupy the niches available. So if we don't blow ourselves away or just die, I think we'll get there. It may be FTL using something like an AC drive. It may be something totally different. I don't know.

I think we'll probably crack gravitational field propulsion, and since metric gradients are exempt from the light speed limitation (wrt external Eulerian observers anyway, which is what counts), someday we'll probably make it to other habitable planets in a jiffy, if the fathomless stupidity of our "leaders" doesn't implode global civilization first. That's why I see this as a race, and a very worrisome race at that - the clock is ticking uncomfortably close to midnight. The advent of this kind of technology could pull our chestnuts out of the fire in a big way. But if I could see any other genuinely encouraging path to the stars, I'd be studying that too. But I just don't see it. Right now it appears to be this, or maybe awful cryogenic suspension through eons of space travel, to get humankind to other star systems, which just doesn't cut it for me.

So my primary driving ambition in life is to see us attain a foreseeable path forward to this technology before I die. I just want to know that it's going to be alright before the lights go out. I don't need to see it happen, I just want to live long enough to see the inevitably of it happening someday. And maybe that clear glimmer of hope at the end of the tunnel will be enough to get people thinking differently, and to make it to the finish line to become interstellar citizens of the cosmos at last.

I think we just agreed!

Nice to see that there's an optimist lurking around in there after all. Welcome aboard, Cmdr. Marduk. Your yeoman will be with you shortly ;

Cough, cough, a testable theory.
Paranjape himself says he doesn't know how to test it, or that we'll ever be able to. But it's worthwhile trying because there is some theoretical evidence it may be there and it would be super cool.

100% with you on that one. Bear in mind - Paranjape was talking about achieving a *net* negative effective mass, so he's right to be cautious about that. But, you know - baby steps. Let's work on a modest proposal for engineering some small mass reduction effect in the lab first. We have every reason to assume that's feasible. And as we inch forward with experimental mass reductions of .1%, then 1%, then 10% mass reduction by exploiting the components of the stress-energy tensors, brilliant theorists like Paranjape can work on strategies to get us into the negative regimes, where things get really exciting.

I come from the school that good science is always skeptical and personal bias is a giant problem. Which is why you have to rely on the scientific method at all times.

I want you to be right. I want you to be listened to. To get at those things, you need someone criticizing your efforts in an honest way. Otherwise, others are just going to throw it in the pseudoscience bucket.

You'll get no argument from me about that. I cherish the adversarial process - I've said it before, and I'll say it again: our debates frequently help me clarify my thinking about this stuff, and focus on the key problems associated with it. I've casually contemplated contacting Paranjape for an interview for weeks, but now that we've talked about it, I'll probably actually do it. There are key questions that have to be elucidated.

It's healthy to have a dollop of optimism though. Consider all of the failures that Edison had with the electric lighting filament, before he finally got it right with tungsten. You have to be kind of a stubbornly optimistic MFer to keep moving forward sometimes. I choose to assume that this can be done, partly because it's the only way that I can explain the physics of my own sighting experience, but also partly because I'd probably give up if I soberly assessed the state of modern technology and the daunting problems associated with real meaningful progress with this. And that's the surest way to fail.

And here's where I go nuts. Those three little words. 'We now know.'

We don't know. We have reason to suspect. We have some evidence for. We don't know it will do what you want it to do.

That is my basic criticism of your argument right there, in those three little words.

Until somebody can refute Paranjape's finding that the positive energy theorem doesn't apply to our universe, or his finding that positive matter can generate negative effective mass solutions within the context of GR, then it *is* fair to say that "we now know" those two things. That's how science works, man: you build on top of credible peer-reviewed findings, which in turn are built upon solid theories like GR. It's not a matter of certainty; it's a matter of faith in the process. And the stuff that you're standing on to reach the next step is always being examined, and when it fails to hold up, we climb back down to where we went wrong, and start building up again on a new, firmer foundation. All knowledge is tentative to one extent or another.

But we do the best we can, and when a fault is found, we say "oops - it seemed that we knew that, but that turned out to be wrong, let's back up and start over from the place we went wrong." Right now, nobody has posed a credible challenge to Paranjape's findings, so it's reasonable to accept them at face value. I'll be the first to change my tune if it's overturned in the future. But if we all kept our eyes on the groaning and teetering edifice that we're standing on: "oh man - that bolt looks loose...and that plank is buckling a bit down there...and who laid this slab in the first place - some crazy guy over a century ago? Dude this is not happening - I'm climbing down from this MFing thing"...what good would that do anybody?

It's also very interesting that whatshisname references a key insight - and problem - with negative energy.

He says that if you have a 5kg mass and a -5kg mass, the 5kg mass will be attracted to the -5kg mass. The -5kg mass will be repulsed by it.

So the 5kg mass would chase the -5kg mass through the universe if they were in space. For free, for forever, you'd have thrust, these two weights chasing each other until the end of time - or unless they hit something.

Which gets back to my thermodynamics problem, because you just created a perpetual motion device and created energy from nothing.

No-no. I know it seems crazy at first blush, but this has all been dealt with all the way back to Herman Bondi's work on this. You start with a positive mass and an equal magnitude of negative mass, so your net mass is actually zero. As they accelerate together, the positive mass acquires positive kinetic energy, and the negative mass acquires an equal magnitude of negative kinetic energy (1/2-mv^2). So the net mass-energy is still zero. Same goes for momentum (+mv + -mv = 0mv). And in the reference frame of the pair of masses, they're both in free-fall, so they never feel any force - they're both in an inertial reference frame. I can't recall exactly how the collision dynamics works out if they hit something, but I think the idea is that the positive mass would transfer positive kinetic energy to the colliding body of positive matter, and the negative mass would transfer an equal magnitude of negative kinetic energy to the colliding positive matter, so it all sums to zero in the end.

It's totally the most effed up theoretical proposal in the history of physics, but everyone who's tried to shoot it down, has turned into an advocate instead, because all the math and conservation laws and so forth work out. That's why it's such an awesome idea - it seems intuitively impossible, but it totally kicks ass, and throw open the prospect for manned interstellar spaceflight in the process.

It all comes down to "can we actually produce a negative effective mass to interact with?" I sure as hell hope so. And as the years go by, it's looking more hopeful all the time. So I say let's figure it out and try it.

Thanks for the great explanation. This is kind of arguments that we need. Now I have motivation to invest more time into learning more about what you and @Thomas R Morrison proposed and getting closer to the full picture.

As you said Tera-hertz radiation is between microwaves and infra red. That's still very low energy region on astrophysics scale. What I found during my digging is that a single Gamma ray can contain about 1,000 time more mass-energy, in electron volts, than any nucleon, like proton or neutron. So if @Thomas R Morrison is right, and negative Poynting vector can be made, than we have negative mass that can easily match mass-energy of normal matter. Obviously Gama rays are so energetic that they would tear apart most known materials.

I would like to appeal to you to turn to the max your creativity and the inner devil's advocate and temporarily switch to Thomas' side. Just in case if there is some accidentally overseen possibility that negative Poynting vector is mathematically valid.

I've been digging into the issue of a negative Poynting vector to see if it applies in the context of photonic metamaterials, because it seemed to me that Hal Puthoff had considered the prospect of a negative Poynting vector to produce a mass reduction via THz radiation upon the bismuth/magnesium sample that he looked into for Linda Moulton Howe back in 2012 (the THz frequency was related to the thickness of the layers of metals, not its energetic content). It turned out to be an unbelievably hairy subject that took years to decisively settle in the academic literature. Eventually everyone realized that none of the electromagnetic stress tensors that had been employed previously to analyze the Poynting vector and energy flux within ordinary positive-index materials were valid within negative-index metamaterials: the Minkowski stress tensor, the Abraham stress tensor, the Maxwell stress tensor - they all failed to describe the actual physics within metamaterials. Iirc, some of them predicted a negative Poynting vector, while others didn't, but they all gave the wrong experimental values in the end. Only the Helmholtz stress tensor was able to accurately model the energy fluxes and so forth (which was established experimentally, I think in 2016), and that required microscopic lattice analysis which the previous equations neglected. And it turned out that with every combination of effect possible: negative phase velocity, negative group velocity, and even negative energy flux - in combination with any combination of positive factors, or none at all - the resultant Poynting vector always turns out to be positive, which seems crazy, but it's true. So Hal Puthoff couldn't have anticipated that in 2012, if in fact that's what he was considering (and I bet it was). I don't hold it against him - it looked promising to me too, and a lot of optical physicists were surprised as well. But optical metamaterials were a new thing; it took awhile to get it all figured out.

But there are other situations that do appear to involve a negative Poynting vector (see post #78) and the solution using the Helmholtz stress tensor for metamaterials analysis elucidated a pair of phenomena at work in these kinds of materials: electrostriction and magnetostriction, which appear to be forms of electromagnetically induced mechanical tension acting along the boundaries of layered materials. So now I have to figure out what that's all about, because that's an entirely new and potentially promising direction for manipulating the electromagnetic stress tensor using photons. Basically anything that induces tension, instead of pressure, should provide an avenue for mass reduction. But you have to account for all of the forces and energies involved, to find out if the net effect is positive or negative. Which frankly is a frickin' nightmare in real-world materials, and why I've shunned materials science my entire life. But I'll keep chipping away at it, and let you know when I find something interesting. Because what we need now are viable experimental concepts, to get the ball rolling with this stuff, and even a .1% mass reduction in the lab would be a killer start.

But it's far more difficult than simply looking at the positive energies of high-frequency photons. Those don't produce negative mass. It's actually quite tricky to produce negative components like tension. It can be done, but typically only to a modest extent, which isn't very useful. Positive energy is easy by comparison: simply heating up a sample makes its mass increase. So if you want to do that, you could focus on designing materials with a huge specific heat capacity, which somebody's probably working on right now. Or just add more matter. But that won't get us anywhere with metric engineering or reactionless propulsion - we need to reduce rest mass so we can eventually produce an object that exhibits a net negative effective mass. Everything pivots on that. And it's a whole lot trickier than blasting a sample with gigajoules of energy, so this is going to take a *lot* more study and creative thinking.

 

[withoutlimits09]

I think we need to create propulsion system that generates energy on the basis of the number of words Morrison writes on this forum! Almost free energy!

 

[Realm]

It's also very interesting that whatshisname references a key insight - and problem - with negative energy.

He says that if you have a 5kg mass and a -5kg mass, the 5kg mass will be attracted to the -5kg mass. The -5kg mass will be repulsed by it.

So the 5kg mass would chase the -5kg mass through the universe if they were in space. For free, for forever, you'd have thrust, these two weights chasing each other until the end of time - or unless they hit something.

Which gets back to my thermodynamics problem, because you just created a perpetual motion device and created energy from nothing.

That's the runaway motion I was referring to with that sports car with a negative trailer analogy. The math can bend the rules, but it sure feels like cheating instead of being physical:

Such a couple of objects would accelerate without limit (except relativistic one); however, the total mass, momentum and energy of the system would remain 0.

This behavior is completely inconsistent with a common-sense approach and the expected behaviour of 'normal' matter; but is completely mathematically consistent and introduces no violation of conservation of momentum or energy. If the masses are equal in magnitude but opposite in sign, then the momentum of the system remains zero if they both travel together and accelerate together, no matter what their speed.
...
So once this runaway phenomenon has been revealed, the scientific community considered negative mass could not exist in the universe.

Negative mass - Wikipedia

This paper argues that it's even worse than that and even isolated negative masses will lead to runaway motion:

The conjecture of the existence of negative masses together with ordinary positive masses leads to runaway motions even if no self-reaction is considered. Pollard and Dunning-Davies have shown other constraints as a modication of the principle of least action and that negative masses can only exist at negative temperatures, and must be adiabatically separate from positive masses. We show here that the self-reaction on a single isolated negative mass implies a runaway motion. Consequently, the consideration of self-fields and relevant self-reaction excludes negative masses even if isolated.
...
Concluding, self-reaction leads to the final virdict against the possibility of existence of negative masses that would lead to a catastrophic world.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.54.4573&rep=rep1&type=pdf

 

[Realm]

This is starting to feel more like a religious or political debate than a rational or scientific one.

That's what I have been saying for a while, and apparently Thomas has now even started throwing in variations of some of the old fundie favorites, like "materialism is a religion" and "disbelief is just like belief".

The fundamental difference between scientific and religious debates is really quite simple. It's just a matter of sticking to the facts and stating things (including uncertainties) as they are. Like you said:

And here's where I go nuts. Those three little words. 'We now know.'

We don't know. We have reason to suspect. We have some evidence for. We don't know it will do what you want it to do.

That is my basic criticism of your argument right there, in those three little words.

All that disinformation and misrepresentations have just led to a conversation where most of the energy has been spent correcting false information and false impressions others have had because of it. Scientific discussions largely avoid that with requirements of supporting evidence or references for the claims that have been made. As I have said all along, there's really no point in discussing about some imaginary link between metamaterials and anti-gravity when nobody has given any credible references that would have stated anything along those lines. But apparently it doesn't matter even when it has been already shown it doesn't work that way, with supporting references. It's a never-ending story with true believers.

Mistakes are understandable, but when they are repeated against all objections and evidence, they become dishonesty. And if distorting the facts is bad, doing it for people and what they have said and done is even worse. Thomas hasn't done that just to most of what I have said, but also to scientists he has referred to, like Paranjape, and even to his idol Puthoff, and apparently still continues to do so:

And it turned out that with every combination of effect possible: negative phase velocity, negative group velocity, and even negative energy flux - in combination with any combination of positive factors, or none at all - the resultant Poynting vector always turns out to be positive, which seems crazy, but it's true. So Hal Puthoff couldn't have anticipated that in 2012, if in fact that's what he was considering (and I bet it was). I don't hold it against him - it looked promising to me too, and a lot of optical physicists were surprised as well. But optical metamaterials were a new thing; it took awhile to get it all figured out.

As I have stated a number of times now, and shown the image of the letter Puthoff sent to LMH at least a couple of times, Puthoff only mentioned there's prior research for a similar waveguide structure, and that there could in principle be a significant result. He didn't specify what he thought that could be, but Thomas still continues to push his own fallacious ideas to Puthoff's mouth with great certainty and is now even giving him a forgiveness of such an unproven sin.

And by the way, that very result of Poynting vectors being always positive was stated in research that Thomas himself referred to earlier, and that was published in 2006. It shouldn't be that hard to "anticipate" things that were known at least 6 years before. And it shouldn't be that hard to anticipate the resulting energy is positive, if even the physicist who originally proposed such materials stated already back then, 50 years ago, that it is so. Seeing what past research contains should be even easier if you happen to be a psychic remote viewer travelling outside your body:

Puthoff, Price, Swann and several others in the SRI team shared the same explanation for "remote viewing". They were convinced that remote viewers were leaving their bodies and travelling to the locations they were describing. They held in common a jargon phrase for this - "exteriorization with full perception". The phrase was originated by a man whom most of the team referred to as the "Source", the "Founder" or even the "Commodore". But the Commodore was not a member of the U.S. Navy. He had given himself the title when he formed his own paramilitary "Sea Organization" in 1967. The Commodore was none other than the creator of Scientology, L. Ron Hubbard.

The Hubbard Intelligence Agency