Thoroughly upvoted and discussed "The first room-temperature ambient-pressure superconductor?" https://news.ycombinator.com/item?id=36864624
has barely fallen to second page yet, but as the topic is of exceptional interest, and under development, and Lowe's commentary is usually welcome and well received on HN, maybe some duplication can be justified in this case?
One odd thing that I've not seen any discussion on: the reported heat capacity of LK-99 decreases above 250K, which is pretty atypical. Has there been any commentary on that?
"I work in the field [...] we don't believe a word of this. [...] The data set in Fig. 4(b) is also a treat. It is VERY unusual when the heat capacity decreases again at high temperatures. This can happen at low temperatures, but not at high temperatures. [...] My personal assumption is that the authors measured an insulator, so no current flow and therefore no voltage occurred (4-point measurement). This would look like a superconductor. But if you then turn up the current (i.e. the applied voltage), breakdowns may occur and a current begins to flow. That would explain the sharp increase."
He sounds rather bitter and arrogant. He basically just called them idiots. As if none of the researchers would have noticed the measurement error. Perhaps he’s right - we’ll know in a few days I assume. I do hope they are right though not only because it would be a huge leap but also because I’d love to see this guys reaction.
Lee and Kim have been working on this stuff for a long time. They published prematurely after major falling out within their institute.
This isn't 1 experiment as the Germans seem to think. There are multiple papers, patents, etc.
The main focus of these papers has been to make huge claims and make replication very easy. They are "all in" and they want others to call.
If they were bluffing they would be heavy on results and light/secretive on how to make the stuff (trade secret, etc).
That's why there are 2x papers published within 3 hours, both with different authors, and you have one author telling New Scientist he did not approve of a paper naming him as an author.
“Damning” is the wrong word here. “Damning” would be “oh, look, the researchers forgot that the plot showing zero voltage also shows current dropping to zero. They’re clearly measuring a bad contact.”
But the papers don’t show that. There’s no obvious contradiction unless you make some big assumptions.
A 4-point measurement of an insulator would show zero current, as far as I know.
A more plausible idea IMO is that it could be a 4-point measurement of a highly inhomogeneous sample. If the current probes make contact with conductive parts of the sample, and there is a conductive path between them, but one or both voltage probes are not contacting the conductive path, then the voltage measurement would be garbage and potentially zero.
I don’t think this is much of a problem when measuring conventional conductors (you don’t need a particularly good contact, which is much of the point), but a lot of superconductors are oddball materials where, under conditions where they fail to superconduct, they barely conduct at all.
So maybe the sample has a conducting phase and an insulating phase?
Wouldn't it be odd for an amalgam of lead and copper to be non-conductive?
I know they were formed from sulfur compounds, but the production process should have eliminated those compounds, and the final forming is done in a vacuum so there shouldn't be any oxide generation to form non-conductive barriers.
I don't know much about the process but shouldn't they be testing resistance in a superconductor?
It’s not an amalgam (that means a mercury alloy) or any metallic alloy. It’s an oxide (more complicated than that but there’s more oxygen atoms than metal atoms).
Amalgam can also mean, "A mixture or combination of different things" such as "an amalgam of musical genres" or "an amalgam of unsavory dog food flavors", which, since we aren't talking about mercury at all, nor are we talking about any form of dentistry, should have be evident and deducible from the context.
Came here to mention this.
Here is a full deepl translation of the post, for those who are interested (in the above linked post of a blog the blog author recites a mail from one of his readers):
"I work in the field and we discussed the preprint a bit in the research group this morning. In a nutshell, we don't believe a word of it:
Fig. 1(a) and (c) are implausible. Normally, this sort of thing looks like this. Note the gradual increase at low currents, this effect is especially expected for magnetic fields.
Also Fig. 1(d) cannot be correct. At Tc ~ 400K the Meissner effect would displace a much stronger field than 10 Oe = 1 mT. I.e. the distinction between FC (field cooled) and ZFC (zero-field cooled) should not be so pronounced. It should look more like this.
What the authors might mean is that they are outside the Meissner range, which can occur at higher magnetic fields (keyword: Type II superconductors). This then looks like this.
But in this case the temperature dependence does not agree at all with the critical currents of Fig. 1(a) and (c).
And also that ALL values in Fig. 1(d) are negative is extremely unusual, but this could perhaps be argued.
The data set in Fig. 4(b) is also a treat. It is VERY unusual to see the heat capacity decrease again at high temperatures. This can happen at low temperatures, but rather not at high temperatures.
I know the described experimental setup / cryostat very well. There is no reasonable reason why the authors did not measure at higher temperatures to show that the behavior above Tc ~ 400K is significantly different. E.g. a temperature dependence of the resistance would have been mandatory.
In general, the paper is very poorly written. The data are not adequately discussed, the explanations are poor, and the papers cited are rather, shall we say, meager. This does not inspire confidence in what the authors have measured and want to have seen there.
My personal guess is that the authors measured an insulator, accordingly no current flowed, and thus no voltage occurred (4-point measurement). Then it looks like a superconductor. But if you then turn up the current (i.e. the applied voltage), there may be breakdowns and a current starts to flow. This would explain the sudden increase."
Lots of people are saying there should be a quick turnaround time here for trying the replication. I wonder how much it would cost to try and replicate this, in materials, labor costs, and vacuum furnace time/costs. My naive thought is that that labs in general aren't just going to drop everything to try an replicate every instance of someone declaring they've discovered room temperature superconductivity. Seems more like a "there's a lull in paying work, so hey, why don't some of you junior technicians try this out" thing? Anyone have insight into this? I suppose a university lab might have more leeway here to try out spur of the moment experiments? Maybe this is a "I'm personally interested in this and I'll work in the evenings to test it out, instead of on company/university time"? Or are the authors high profile enough in the community that it meets a certain threshold of credibility that it seems more worthwhile than the average?
I don't think, at least generally, work is as rigid as indicated. At least at white collar jobs, and especially a research lab, and most especially a university research lab.
It's a reasonable enough paper, and replicating should be pretty easy (an undergrad could do it). Because the implications are so massive if true, people are going to jump on it.
From the linked article:
> You can bet that furnaces in solid-state materials labs around the world have been cooking yesterday and today to try to reproduce its synthesis and the properties, and we should be hearing about the results of these experiments very soon. The first samples should be coming out of the quartz vessels. . .sometime tomorrow, perhaps? Depends on what was available around the lab!
Yes, that quote from the article makes it seem like everyone is dropping everything and jumping right on it. I'm wondering how likely that is we'll find out this Friday vs. in the next couple of months, as people get around to it.
Friday is more plausible than a couple months. If the radio silence ends up extending well-into next week, people are having trouble replicating and want to cross their ts before calling it out as fraud.
That depends on how easy it is to replicate, and if it is true. If it is easy (the 24 hour in the furnace is really long enough for everything to get to temperature - 10 minutes is enough in ideal cases) then we will get lots of success Tomorrow. If it is hard, well we will get a lot of failures, but a few will try again an in a month as they refine technique will report a success.
If it is false we may never get a final report, just everyone gives up on reproducing it. (though with the hype we may see it like cold fusion were a few not very good researchers keep it alive via badly done experiments).
If someone claimed to have a complex proof, i dont think people would stop and drop everything.
If someone claimed to have a constructive solution to p=np, claimed to have implemented it, and put the code on github - yeah i think lots of people would drop everything to run it and see if it works.
Im not a physicist, but maybe with the relative ease on making this material (according to other comments) it is more like the second situation.
For real; the original paper is kinda shitty in terms of data presentation, and there's significant value to make a follow up paper to create data and try to get your name out there.
The author of the paper apparently says it wasn’t supposed to be leaked and that it needs more work, but he stands by his results and will assist anyone trying to replicate, which sounds pretty steadfast to me.
They have patents… this is the sensible approach to take with your intellectual property well defended. Between the patents and the published paper establishing his role and thus Nobel eligibility…
At this point assisting anybody who wants to help prove him correct (and I know that I’m making the assumption that he genuinely believes he has made what he claims in the paper with the mechanisms and methodology as outlined) will just help secure get rich faster and make his Nobel prize even more secure.
Polycrystaline materials are kinda finicky so more samples helps eliminate the error bars. So obviously why didn’t they do heaps of samples and have a longer paper? … Money! They got funding for quantum physics based sensor/detector research and this appears to have been a happy accident, so naturally they kept their heads down, got their patents (they have multiple patents each of which costs money) and did a little bit more work to be absolutely sure, then as soon as it was smart, they published their results and are now going to let the entire world excitedly double check their results… because the results if true, are fucking awesome…
Of course the world wants to replicate this, no one wants to be waiting for someone else to confirm a breakthrough this big… I bet there’s even some corporate labs doing a little work on replication too, so some smart managers in various industries can factor room temperature superconducting materials into their designs and future plans sooner, because otherwise their competitors might be! (Obviously there’s not going to be a lot of this since most companies don’t have internal science groups but the Lockheed-Martins of the world, the Daewoos, the Mitsubishi Heavy Industries, the Ratheons … I’d be surprised if they didn’t already have someone somewhere in the world who is still currently making batches and putting them into furnaces because the material is cheap and you can get a lot more certainty from additional samples if your are prepared to pay for the work. I’d be dammed sure someone at General Dynamics is making some because it would massively help them convince the US Navy to give them more funding to continue work on railguns!
It doesn't require the kind of equipment that you have to justify to accountants and run at full capacity. And while the reactants are things that I believe most labs won't have at hand, they are the kind of thing anybody can buy on the web to arrive this week.
Whether people will stop what they are doing to verify it is literally a matter of people stopping what they are doing. University labs are usually quick on that.
From what I recall of the original paper, 1-2 hours of actual labor with equipment and reagents many labs already have on hand--although it required 24-48hours in the furnace at each step which is the only reason for the delay and why the article author mentions we should see results tomorrow. So, trivial enough most people in similar labs already spent more time discussing the implications than actual labor/investment to replicate.
Fleischmann and Pons' famous cold fusion result was announced on March 23 1989 and a spate of replication attempts followed in the ensuing weeks; by April 30 1989, the NYT ran an article calling cold fusion dead due to the large number of reported negative reproduction attempts.
Scientists can move far quicker than you expect, and a positive or negative replication of this superconductor claim should be a very easy publication to grab. It would definitely be worth alloting a few weeks of grad student time to replicating this ASAP to get that publication.
The fact that there are other (competing?) scientists doing superconductor research suggests there will be organized attempts to verify it.
That said, I remember reading about shockley having ideas about the transistor that he only fessed up to as his other more open collaborators started understanding the phenomenon.
> My naive thought is that that labs in general aren't just going to drop everything to try an replicate every instance of someone declaring they've discovered room temperature superconductivity. Seems more like a "there's a lull in paying work, so hey, why don't some of you junior technicians try this out" thing? Anyone have insight into this?
Labs all over the world are dropping everything to replicate this. It's simple self interest.
It only takes 2-3 days and the people involved in the paper are credible.
If it's real, your lab would be at the forefront of the biggest revolution since the transistor. If it's real, there will be hundreds of papers on the topic by next year. Your lab could be the one to discover a variant that can carry more current, that could have patent on the material of the future power grid. The papers that provide the basics for how this works and the data that everyone will be using will get 100k+ citations in a few years. The PhD students that become experts in this will be in high demand everywhere.
I’m sure this is on Applied Science’s (a YouTube channel) radar. He recently went on a deep dive on making YBCO superconductors so it’s right up his alley.
Under a week of work to publish potentially the highest impact paper of your PhD (especially if you're first)? I'm guessing most students would take that chance.
The synthesis outlined in the paper takes about 90 hours, but basically all of it is just waiting for the material to bake in a furnace.
I'd expect some lab out there to report a result by the end of the week. The synthesis really is super simple, just grinding powders together and baking in a furnace. Granted, the final product has to be baked under vacuum, but that's not super difficult to achieve. The authors sealed the material in a quartz tube and baked in a standard furnace.
I'd bet the country would be transformed by this. SK universities (SNU, KAIST) would rocket in reputation for solid state physics research. Massive money inflows to the country from production of the material. Deep down I think most of us realize that this will probably turn out to be nothing.
I’ll draw an analogy to the LLMs and diffusion models that have lately rocked the computer world. These things are straight up science fiction. I would have said computers would have never been capable of art and poetry. It was all fantasy until it was suddenly reality.
We’ll probably know if this can be replicated relatively soon. And if it can it will kick off a whole new branch of materials science and begin a multi-year race to commercialization.
We are facing gigantic challenges in energy and climate. We need the win, so my fingers are crossed.
LLMs were/are massively overhyped though. Like it’s not even close to the sort of transformation they promised. Neat tech yes, world-changing solution to all of our problems? Very hardly, unless a very significant effort is spent (and yet undiscovered tech invented) to eliminate all of its significant practical problems.
Academics (and similarly venture startup founders) like to sort of jump to conclusions along the lines of “discovery was the hardest part - now this thing could enable ... in the next X years” at the end of a paper. And then people spend many decades to actually reduce this to practice. So 90% of work belongs to applications, not technology in on itself.
1.2 years ago if you claimed that an AI will just come out and make artists mass panic you would be laughed at. Now art is somehow just 'solved'. Progress is continuous and massive from Midjourney v1 -> v5
Well, that’s exactly what I’m talking about - new unproven tech that created more problems that it solved. It didn’t “solve” art since that is meaningless without a human artist. Instead, it stole popular concepts and is regurgitating it without any originality or thought put into it, and then used “instead” of real artistical works by those who don’t really understand art, but just need “content”.
In other words, merely copying/reproducing something is emphatically not art.
The same thing happened with traditional (painting) art and photography - the latter didn’t really replace it but just supplanted it in the areas where one wasn’t really looking for art but for mere reproduction of reality. And then over time, photography itself has evolved into art, since people have learned how to channel their inner self through it, and aimed at quality instead of “quantity” (and unlike the former, the latter by itself became trivial). I don’t see the same happening with generative models quite yet (heck, they didn’t really replace photography either!)
I don’t think you realize what’s happening. In it’s 1+ year existence, it has already seeped into media production, art, design, architecture, engineering, pharma, agriculture, education and basically every field dealing with digital information. We don’t hear it but there is massive change happening underneath our feet.
In the immediate short term, the power level supported is too low for the real shiny applications that everyone talks about.
But the main one that is screaming at me for this technology sitting in front of us is SQUID sensors and RF antennas that will operate in the lower power range of the potential applications spectrum.
Search "superdirective superconducting antenna". With normal conductors the directivity of an antenna depends on how many wavelengths it spans; the summation of the currents over the effective aperture. With superconducting materials you can exploit the weirdness in current distribution to make very directional antennas that are small relative to the wavelength.
It could be a game changer for making efficient directional small receive antennas. Normally electrically small antennas are just super inefficient but it's made up for either on the transmit side (like with high power AM radio) or with most of the gain coming from some low noise amplifier (like small UHF wireless devices).
Probably not. It will make the really small really inefficient antennas stuck in things like 2-5x better. But they still won't be outperforming full size resonant non-superconducting antenna.
There’s a ton of electromagnets that are super cooled (like single digit K cold) so that it can maintain a large magnetic field. While this is only the first step, pretty much any application that does something similar can be replaced with this room temperature super conductive material.
Not only products would be impacted but experiments too, particularly particle experiments. All colliders need some sort of ridiculous magnetic field which uses a close loop helium chiller.
Long term wise, anything that uses electromagnetic fields would be impacted, like motors and generators. You in theory can get stupidly efficient motors (99%+) motors with super conductors.
Most power loss in a computer comes from MOSFETs, not resistive loss. Which isn't to say that RTP superconductors wouldn't open up wild new possibilities.
Much of the power consumed, and heat dissipated, by conventional processors comes from moving information between logic elements rather than the actual logic operations. Because superconductors have zero electrical resistance, little energy is required to move bits within the processor.
Obviously this isn't much benefit since the vast majority of applications can't be liquid nitrogen cooled (and computing has followed "what consumers will buy" on progress).
That changes substantially if superconductors will keep working when put in my pocket.
If yesterday's comments were correct, you can strike the power transport and storage use cases, as this material has a pretty low electric current density.
Wouldn't less power loss not just mean lower power consumption, but the ability to run it at higher speeds while keeping the same cooling technology we current have?
Not only less power consumption on Computers but a 100x improvement in clock speeds, a 500GHz CPU would be absolutely insane.
Whether or not we can manufacture/shrink the superconductor circuits enough to be competitive with semiconductors is another question, but my naive interpretation is that if you can make the superconductor circuits 100x larger than a silicon circuit, it is still going to have significant advantages.
> A global power net. No solar power during the night? Just produce it on the other side of the planet.
This sounds like it has interesting ramifications for global politics. At the beginning of the Ukraine war, one major lever the Russian government had was to enable blackouts in Ukraine. Makes you wonder how a global power network could work in light of international conflict.
A lot of people are talking about very cool practical use cases, but I'm here just thinking 'all of our trains could float, wouldn't that be neat?' [0]
As far as I can tell the critical field, the maximum magnetic field it can withstand before turning into a regular conductor, is relatively low at 0.3 Tesla. In superconductors like YBCO, it's often more than 100 T. If critical field cannot be increased this will limit applications.
Near term may be useful for devices which take advantage of quantum effects such as Superconducting QUantum interference devices or SQUIDs.
Use in microelectronics may be possible, but is likely quite difficult. Making complicated structures out of this material will require radically new microelectronic manufacturing processes. HTSC microelectronics don't exist as far as I can tell.
If critical field can be improved things get interesting. If it can be increased to that of known HTSCs at liquid nitrogen temperatures(critical field scales with temperature), that's interesting because this material should be cheaper.
If it can be increased moderately at room temperature, there is the potential for it replacing rare earth magnets because the material should be cheaper.
0.3 T is pretty insignificant for everyday use - you need some pretty big coils carrying around 10 A to produce that sort of field. For something like this, the benefit would be in just making wires out of it for driving currents without loss of power (no resistance, no heating). Think big bulky overhead wires - but it's all moot if the material isn't a superconductor.
And can you also explain "indefinite levitation" to me? IIRC you can do some levitation over metallic surfaces or magnets, but that would require power, wouldn't it?
MRIs would be another revolutionized field. Cooling is a big size constraint and cost driver. You would still need a large amount of power if you want to have clinical scans at 3T or 5T, though, but in wealthy countries the number of MRI machines would for sure proliferate and it would probably become more routine. Low-resource environment deployments may become a tad more feasible, to be honest the power requirements will still probably be too high, but at least you wouldn't need an always-on source.
I’m just thinking aloud here but would this enable actual perpetual motion machines? For instance, wouldn’t the pushback from the quantum locked superconductor be an infinite source of energy?
I think it'd be valuable for anything that conducts electricity, and where resistive losses are significant or where strong electromagnets are desired.
So, long distance electricity transmission, motors, generators, MRI machines and magnetic confinement nuclear fusion reactors for example.
That said, the material as synthesized might not be very good for some particular application. The current handling capacity might not be good enough, or it might not be physically strong enough to use as motor windings.
I don't know enough to do the comparison, but I'd be curious how this new material holds up when compared to copper or aluminum wire in terms of current capacity, weight, strength, and cost of materials. One of the big reasons for skepticism about humanity's prospects for converting to a non-fossil-fuel based energy system is that there just isn't enough of the important metal resources to build all the batteries/EVs/transmission lines/solar panels/windmills we need. I myself am skeptical of the skeptics because I think the resource bottlenecks are overstated and there are usually acceptable workarounds, but I do think copper is going to be in very high demand over then next several decades. If we have a good, cheap copper alternative then that solves that problem. (It also introduces another, as we would then have to deal with enormous quantities of lead-based cabling.)
Explosive weapons chargeable to any yield. Take a loop of superconductor charged to the desired current, then warm it beyond its critical point, dumping the electrical energy into immediate heat. A 120mm tank shell is in the 10s of Kilowatt-hours. No more special chemicals, just this lead based super conductor and 20 minutes on an EV fast charger. Don't forget to take it off the charger!
I mean, it depends a lot on how ductile a final product is. High temperature superconducting "wire" took a long time to become realistic. If you somehow made a ductile and inexpensive wire out of it then it's going to be everywhere (and lead poison everyone for generations, but that's progress for you).
Of course if you can make wire out of it, I wonder how much smaller your fusion reactor can get?
There are a lot of applications for even a thin film, consider spray coating a resonant cavity with it.
I'm sure there is a way to improve almost anything you could think about if you start talking about making CPUs with lower heat dissipation, perhaps enabling 3D designs and much more efficient computing... [edit: obviously there is a limit from literally the entropy in computing and transistors are most of that, I wonder if the superconductor is a good thermal conductor...]
I'm sure there are at least 222 startups that have some idea they're pitching right now ;-)
This is an extremely useful summarization of the original paper.
> The authors believe that the modified/strained structure of their material creates a large number of “quantum wells” between particular lead atoms and the adjacent oxygens of the phosphate groups bound to them, in effect making a two-dimensional “electron gas”. They propose that electron tunneling between these quantum wells, which are between 3.7 and 6.5 Ångstroms apart, is the superconducting mechanism. I am not enough of a solid-state physicist to judge this proposal, but the authors are making a detailed mechanistic claim that is subject to experimental proof, which is very good to see, and and they adduce a good deal of data to back it up (x-ray diffraction, EPR, and more). And they demonstrate the behaviors that a superconductor should have, such as the Meissner effect (expulsion of a magnetic field), sudden resistivity changes at a critical temperature (bizarrely high though that is in this case), current-voltage (I-V) plots at different temperatures and under different magnetic field strengths, etc. If these data reproduce, the superconductivity of this material seems beyond doubt.
I don't think the actual proposed superconductivity mechanism is the relevant part of this paper. It is much easier to prove that this is superconducting than to prove why. And in a sense it is a bit less relevant. Although developing a working theory for room temperature is also probably worth a Nobel prize, so I am willing to bet some theorists are also running to their blackboards as we speak.
Yeah. BCS was proposed a half century after the first conventional superconductor was discovered, and even today we don't have a convincing mechanism for "regular" high-Tc superconductors. But if it superconducts, it superconducts, and research into the how is useful but not a blocker to using it.
That depends. If it super conducts, but it isn't useful in the real world, then we will be waiting for theory to - hopefully - give us some insight into how to improve things to useful.
This only can carry a small amount of current. I'm not sure how to figure out what small means (numbers are given in the article if you know how to use them!), but if the losses using regular wire are less than the energy needed to make this stuff then it isn't useful.
This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical. Or it make leach lead into the real world making it not safe to deploy.
There are probably other ways this can turn into a "it works but isn't practical" thing that would force us to wait for theory (or luck!) to point to something better. What I wrote above is what I can think of in a couple minutes. Only time will tell though, I hope it works out.
> If it super conducts, but it isn't useful in the real world, then we will be waiting for theory to - hopefully - give us some insight into how to improve things to useful. This only can carry a small amount of current.
Thank you for this.
> This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical.
Have you been to a hardware store lately? A huge amount of pipe fittings for gas and non-potable water are made from lead. Factories don’t find it hard to work with lead. It might be inadvisable but it’s not hard.
We can argue about the "working safely" part, but in terms of "does this make it impractical?" the answer seems to be no under the current global regulatory environment.
Nah. We have a reasonable understanding of fluids. It's just that the two things we say as simple explanations (the plane pushes air downwards causing an equal and opposite reaction to push the plane up; faster flow on top of the wing "sucks the plane upwards") are both only partial truths.
Sometimes you get arguments between partisans for each of these two simplified explanations, but really both are bogus.
I’ve never understood how this battle could possibly persist, considering that planes can fly upside-down. The fact that Bernoulli’s Principle creates a low-pressure zone on the top of the aerofoil just gives you laminar flow at higher angles of attack.
It really isn’t that mysterious, unless you insist that only a single physical law is allowed to come into play.
> You can build a pretty good mental model of flight with either simplified mechanism, but you end up underestimating performance by a fair bit.
I've never hear of a good mental model built on Bernoulli's Principle. They are either:
- Wrong
- Give no intuition
The key question is /why/ air moves faster on one side, and once you get away from the misconception of same time, I've never heard an intuitive argument.
Redirecting air down:
- makes complete sense
- can be demonstrated by sticking your hand out the window of a car
- works with flat airfoils (sails, kites, etc.), and explains those well too
And the shape of the wing comes in from wanting the leading edge parallel to incoming airflow, and the other edge parallel to outgoing airflow. On a sail, I can adjust the shape. On a steel wing, I can't much, so I make a shape which works across different angles of attack.
All of the other mechanisms, you can gradually work in from there to get accurate models. Toss in air moving to the low-pressure area, and having momentum, and you get why helicopters are less efficient than planes, as well as vortex shedding. It all builds up.
As a corollary, Bernoulli tells you where air moves faster, but that follows from lift. Not the other way around. At least in any model which fits the human brain.
Why are you benchmarking models to human intuition? If you apply the same reasoning to quantum mechanics you'll have a bad time.
I'm sure models can accurately compute how much of the wing lift comes from the suction effect on the top of the wing versus the push on the bottom of the wing.
> The key question is /why/ air moves faster on one side, and once you get away from the misconception of same time, I've never heard an intuitive argument.
Since the air follows a curved surface instead of straight ahead, you could perhaps apply your intuition for centrifugal force. Momentum sort of pulls the air away from the surface.
Counterpoint: A wing with the opposite curvature would work too, just much less efficiently. Your explanation has an element of truth, but an element of untruth. It'd take more analysis to tease them apart.
In the Vsauce video "Do Chairs Exist?" (I highly recommend it!), Michael talks about the concept of vagueness and how defining boundaries can lead to paradoxes. While it was primarily dealing with an ontological perspective, the linguistic perspective of a particular line has always stood out to me. Perhaps it makes a bit more sense in context of the full 40-minute video, but it is:
>"Composites are causally redundant. Believing in chairs is like believing that, while yes, the burning gas from my stove completely describes why the water in a pot boils, there’s ALSO a magical invisible substance called boil-o that comes out of my stove that does the same thing as the flame at the same time, and if there was no boil-o, the flame would warm the water just the same, but there IS boil-o... Chairs are no more real than boil-o. Composites over-determine what happens in the world."
Like your example with lift and fluid dynamics, simple explanations like "plane pushes air downwards" or "faster flow sucks the plane upwards" might be insufficient, but they're at least useful to the layman. It also reminds me of how Richard Feynman answered the question, "What is the feeling between 2 attracted magnets?" by explaining that it would be impossible to give a complete answer. Feynman pointed out that when you ask why two magnets attract each other, there are different levels of understanding depending on your background knowledge. For someone with no knowledge of physics, the simple explanation would be the existence of a magnetic force causing the attraction. However, delving deeper into the question raises complexities that can be challenging to explain.
Feynman highlighted the difficulty of answering "why" questions in general. Explaining magnetic attraction in terms of something else that we are more familiar with, like rubber bands, would be misleading and circular, as it ultimately comes down to electrical and magnetic forces. He acknowledged that some aspects of the natural world may need to be accepted as fundamental elements without a more profound explanation.
This is echoed in the Vsauce video, where defining boundaries and attempting to explain everything can lead to paradoxes and vagueness. The concept of "boil-o" illustrates how composites, like chairs, can over-determine what happens in the world and our own perception, making their actual explanation even more elusive.
We 100% know why airplanes of every shape and size stay aloft, and can calculate lift/drag extremely accurately based on the geometry of the plane and the airflow, in both steady state and much worse conditions. We have great approximations for steady state that make perfect sense and simplify the situation greatly and make it more understandable without simulation, even if they gloss over some details.
Where are you getting this terrible information that we don't know how flight works? Have you ever talked to literally anyone who has worked in aeronautical engineering, or even studied the basics of fluid dynamics?
> This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical. Or it make leach lead into the real world making it not safe to deploy.
Lead is still routinely used in many applications today, either in metallic form, from ICE car batteries, to fishing or hunting gear, or as chemical compound in different kinds of glass. And the same can be said about other heavy metals like Cadmium or Mercury. Industries also routinely work with much more nasty things than lead, so it really doesn't sound like a show-stopper.
In particular, lead is still extremely common in radiation shielding, possibly because the drop in demand for other applications made it so cheap. Lead-lined drywall is the default approach for setting up a radiography, fluoroscopy or CT suite.
> possibly because the drop in demand for other applications made it so cheap
Maybe a little bit. But I think it is more that it is a material with heavy atomic nuclei and high density, and thus effective at blocking radiation. And it is also relatively cheap.
I believe that most of the lead used today is a by-product or co-product of mining other more valuable metals like Zinc and silver. Lead is quite abundant in the Earth's crust and found in easy to access deposits.
I think >80% of the current industrial use of lead is for batteries. It's probably still in the top ten most mined metals by dollar value and definitely by mass.
The mineral containing Zinc is called Sphalerite, which is based on a greek etymology for "deciever" because it commonly occurs with Galena (which has Lead and Silver) and looks similar.
75% of aluminium supply is from recycling aluminium products.
The economy sort of has a "working capital" quantum of aluminium which also grows steadily from aluminium mining.
Lots of metals have very different and complex supply structures and thus completely different $$$ / volume curves for their supply.
Understanding the $$$ / volume curve of commodities is not something that is commonly considered when people try and predict the future. Mining a billion tonnes of Aluminium from an asteroid for example and safely landing it on Earth can never be profitable because the $$$ / volume curve for Aluminium is $0.00 at billion tonne volume.
Engine blocks too. If you go to a scrap yard though you’ll be pretty amazed at all of the stuff they’ve got collected and sorted. Metal recycling (compared to, say, electronics recycling or plastic recycling) has a very clear economic model and financial incentives. If you’re demolishing a building or scrapping old machinery it will cost significantly less to recycle the metal (because you get paid decently by the pound) than to take it to a landfill (where you pay by the pound instead).
TIL! Aluminium is an extremely useful metal, but I would never have thought it would be used for jewelry - I mean, it's not enough for the metal to be expensive, it also has to look and feel desirable, which soft and dull Aluminium definitely doesn't. If you have ever held Aluminium cutlery in your hand, it just feels cheap compared to stainless steel (not to mention silver).
Today it isn't used for jewelry. 200 years ago it was - not so much to wear, but to show off that you were rich enough to afford it. Only royalty could afford things made out of aluminum.
As a young fella, I carried a lot of that lead-lined drywall, it's (obviously) really heavy, and expensive so you got yelled at a lot if you damaged the edges, couldn't just trim it off like normal drywall.
Unfortunately, most companies seem to have little compunction about exposing workers, consumers, or the environment to toxic materials. The use of lead is not in any way a blocker, for better or worse.
Ding ding ding! We still don't know how bikes work, we have a pretty good but incomplete model for lift on airplanes, and no one has the faintest why Tylenol works.
We should figure that out! But we can definitely keep using all the applications until then. (Except for Tylenol, we keep learning how bad that stuff is)
EDIT: It won't let me post more, so here's the answers to responses.
I'm assuming they mean the balance mechanism, and specifically what allows us to balance. How much is it the rider shifting their weight, how much is micro steering adjusts as we move forward, how much is the gyroscopic forces of the wheels, how much of it has to do with the angle of the handle bars to the wheel verse the center of weight.
That said, I'm guessing this one is well understood by experts, but more complex than someone would assume at first glance, and many who have some understanding likely have an incorrect or at least incomplete understanding of how balancing works.
The smart phone is the culmination of understanding a million facts about materials sciences (applied and theoretical), some of which were obvious, some of which were non-obvious. Starting from a transistor you could see from across the room down to ones you can't even see with a magnifying glass.
It's the reason I got a degree in physics, if you have good professors - discussions like this cause you to break down the problem quite quickly in your head in a working model. Think force diagrams, but with a ton more math backing it up.
I actually find the ice skate a better example than a bike. We have all the physics solved for bikes, it's a complicated system but so is everything in motion. Hence we assume a spherical cow for the sake of the problem.
But ice skates... Now that's a funky one. Why do ice skates works? Ice skates aren't sharp bladed, they actually have flats. Ice is not slippery, it's when something is on ice in between our shoes and the ice that cause it to be slippery. Some people think it's the localized pressure of the blade that causes ice to locally melt. Hard to really wrap your head around. But it works :)
>We have all the physics solved for bikes, it's a complicated system but so is everything in motion. Hence we assume a spherical cow for the sake of the problem.
This depends upon the question one is trying to answer. If one is trying to create a bicycle that can self balance, that involves considering different factors compared to trying to determine why certain injuries result in a person losing the ability to balance on a bicycle while others do not. Is the focus the bicycle or the human?
You are correct, a lot of forces are canceling out on the long term(instead of instantaneously) it can easily be manipulated into increasing periods of unbalance in one direction until a point is reached then a separate mechanism is used to force it to a balanced state. Conservation of energy is always in effect. Gyroscope effects that bike wheels can be added with other separate gyroscopes. Thus, a self righting bike. The effect called precession is understood well enough.
How a human is able to manipulate it is simply by using the force of gravity from shifting their weight(moving the center of gravity). However, the movement of the center of gravity has to be perpendicular to the wheels axle. The steeper the angle of attack the wheel has to the ground, there will need to be an exponential increase in distance to move the center of gravity. Once the wheel is parallel to the ground, there will be an undefined distance needed to move the center of gravity.
e.g. What keeps bicycles balanced with or without a rider is still an active area of research, and even the seemingly basic idea that, for a bicycle to be self-stable, it needs to turn the handlebars into the fall, has not yet been proven.
You can write out the equations of motion for a bicycle that will very accurately predict the dynamics. You can put these equations into a numerical simulation and predict motion very accurately. You can change the parameters of the model and do simulations with high confidence. Just because there isn't some neat little equation that says exactly what each parameter change is going to do (without doing the simulation) doesn't mean that we don't understand bicycle physics. It's a silly line of reasoning. Those articles are hyperbolic.
There are things we can characterize to any desired degree of accuracy but that e don't get cute little equations out of... and some of those things are so simple they've been staring you in the face since middle school and you just didn't ever notice their absence from your formula sheets.
This is not the exact same situation being described but it's a similar thing. Being able to put a complex system into a computer and arbitrarily manipulate it still doesn't mean we can extract some simple explanation.
On the other end of the scale, see all the AIs coming out. They're 100% computer artifacts with theoretically no mystery in them whatsoever... but they're just tables of billions of opaque numbers and doing anything with the numbers beyond just running them is amazingly difficult.
As a bit of an aside, most people don't know how bicycle wheels work. There's a whole section in https://en.wikipedia.org/wiki/The_Bicycle_Wheel that talks about how they actually work. It's not tension at the top, it's compression on the bottom.
what do you mean it's not tension at the top? did you misspeak? bicycle spokes are solely under tensile forces. they can't support compressive forces at all. i'm a hobbyist wheel builder and a once upon a time professional bicycle mechanic during hs & college.
if you want to test this take nearly all the pretension out of your spokes and sit on your bike. feel which ones are taught and which ones are completely loose. or just go to walmart. those bikes hardly have any pretension in their wheels.
I wonder if those have less or more breakin issues compared to spokes. With a spoke you have to reset the angle of the bend to the shortest distance between the hub and the rim. But with cables they have to settle in along their entire length.
Doesn’t change the answer. They’re still compressing. They’re just pretensioned.
There are two situations when you can push on a string. One is when it’s frozen, and the other when it’s tensioned. How do you unload a bow string? You push it off the notches.
bro. you're wrong. just build a bicycle wheel some time. it becomes very obvious how they work as you take it through the various stages of tensioning.
Why do you think someone would talk about Brandt’s work if they hadn’t used it?
I’ve built more than half a dozen bicycle wheels. My set, my spare that my brother road (into the ground - my first set and practically the only problematic ones, but he road over bumps without getting out of the saddle), a set my dad commissioned from me, and a pair that he had me build for a friend. All by age 17.
I then worked as a mechanic for two summers of college. I was never the fastest, but if we had a customer we could not afford to disappoint, I or the senior mechanic got the job because my repairs did not come back.
I saved three or four wheels that would have been scrap by unwinding the spokes halfway and building it back up again like a wheel build. Only added an extra ten or fifteen minutes but it works a charm. When a good customer comes in on Wednesday before an out of town bike ride you can’t afford to fuck it up. I think I only built a couple professionally, and usually singles. That’s a lot of labor and few will pay.
There's a lot more creep early on, which is compensated for by a staged tensioning over the course of a few days. They may require the spoke holes in the hub to be radiused, which can be a warranty issue between you and the hub manufacturer. Windup is controlled by a flat on the small bit of spoke used for threads.
They're ok (i.e., made it through Tour Divide with no issues), done well they're certainly better than badly done steel spokes, but it's not clear if the best builds are better than the best steel builds.
That book I linked has another name, “the wheel building bible”. Jobst Brandt earned an obituary in Bicycling magazine including quotes from his friend Tom Ritchey (one of the original mountain bike makers). Jobst was a bike fanatic and a mechanical engineer.
Bike spokes are not loose, they’re under substantial tension. Bolts, I just learned a couple weeks ago, work in the opposite way. A tightened bolt compresses the two pieces of metal together, and when you tug on them, the bolt doesn’t stretch more. The tension instead first cancels out some of the compressive force on the two pieces of metal, before the bolt ever feels more load.
Conversely, all the spokes on the wheel are under tension. When you put the wheel on a surface and push down, the compression cancels out some of the tension on the bottom of the wheel. Cancel out all of the tension, and the wheel turns into a potato chip if you don’t reload it exactly, perfectly on axis. IIRC, none of the prior models or theories for how a spoked wheel works could adequately explain how potato chipping happens. His does.
I used his book to build half a dozen wheels or so and the information it contained to fix many more.
i own the book.. and also The Art of Wheelbuilding - Gerd Schraner
of course in a properly built wheel usually all the spoke are under tension...
i was just demonstrating the fact that the spokes on the upper half of the wheel are supporting the hub and are under greater tension than the bottom ones, the spokes on the bottom half of the wheel should remain in tension, but only through the fact that they are already under tension applied during the building of the wheel.
the fact that the wheel works by tension of the spokes becomes obviously apparent when you start to remove the pretension and then the spokes will feel loose on the bottom half. of course you'd never want to ride a wheel like that because it will quickly become out of true.. just like a walmart wheel.
I think one of us needs to reread that book, because he emphatically denies that tension at the top of the wheel increases. It’s tension at the bottom that decreases.
> of course in a properly built wheel usually all the spoke are under tension...
No, a properly built wheel all of the spokes are always under enough tension you can bounce a penny off them. Always.
no. you're assuming the rim has no deflection which is untrue. if you build a rim out of schedule 80 steel pipe then yea. but 300-400-500g rims on high performance bikes do not act like that. the spokes are constantly loading and unloading tension as they bash through rocks and over jumps. the point is that the pretension on the wheel needs to be high enough the spokes do not loosen too much under these forces. if they do in fact loosen too much the nipples will begin to loosen and unwind and the wheel will become out of balance.
If you’re talking about twisted spokes unwinding, you don’t have to reach zero load for that to happen. You just need to reduce the load enough so the rotational force overcomes friction. Tension will also try to unwind a screw as well. But the thread pitch on spokes is very fine, which lessens that force. If you build spokes like wood screws we would have problems and that has nothing to do with reaching 0 newtons.
You can release a lot of those tensions by squeezing the spokes mid build. Just don’t wait until they’re too tight to do it. I had a pulse in my rear wheel that probably came from doing that wrong the first time. Unless it was a factory defect, I must have overtensioned and warped a brand new Mavic aero rim ever so slightly. Expensive lesson, but it could have been worse.
This dialogue is reminiscent of rec.bycycles.tech arguments with Jobst, ca 1993.
A bike wheel is a linear elastic system, that can be thought of as a superposition of a uniformly set of tensioned spokes as one state, and a set of spokes in compression in the loaded zone (bottom of the wheel) as the other state. So long as the superposition of the two states obeys the limiting conditions (i.e. spokes in tension) they can be analysed separately.
The size of the loaded zone is related to the relative stiffness of the spokes (axial) and the rim (bending), and can be calculated using beam on elastic foundation methods. For typical rim/spoke combinations, this is approximately 4 spokes.
Outside of the loaded zone, spoke tensions essentially don’t change.
Well. I wish we could sit in front of a bicycle wheel and discuss it. Because I have a feeling we are shooting arrows at different targets. As a mountain biker I'm more interested in what happens when an extreme amount of load is applied to the wheel, not the model with assumptions applied. Definitely a difficult concept to discuss with only text. Anyways.. glad to have a good discussion with you about bicycle wheels. Don't find many people like you. :)
I think I would have been a mechanical engineer if I were born 20 years earlier or 20 years later. Software was just new and shiny enough and it let me build things with my mind, at a time when I believed I was clumsy (I actually have always had excellent fine motor skills, it's macro motor control I lagged behind in). One of my better friends in college was an ME. Learned all sorts of things about metal fatigue and oddly enough picosecond lasers from him.
I don't know if I found Lego or Lego found me, but I definitely think in terms of shapes. I was past my midlife crisis before I realized that I don't have a large working memory (smaller than average in fact) it's just that I've been doing mind palaces without pictures since I was very small. When I'm thinking of large computer systems I'm essentially thinking of them as physics problems.
I really should figure out space to have a bike again. I never rode when I lived in Seattle (Seattle drivers are nuts) but I don't live there anymore and I need to catch up on 20 years of tech.
I think you're both in violent agreement using different terms.
You're looking at the macro "It's all in tension" (superposition of two states) and hinkley is looking at the "bottom is a compressive change" (dynamic portion of the load).
What I'm not clear of is if you think that the upper spokes change tension between the unloaded case and the plain gravity load case (force on hub down, ground on rim up at the bottom), or if you expect the top half spokes to increase and the bottom half to decrease in tension. I think this is what hinkley thinks you think.
That was indeed my interpretation of that half of the conversation. That they were claiming that the axle is suspended (tension increases with downforce) by the spokes above the midline of the circle, which is what Brandt vehemently contended was false.
Pretty sure he did, but I don't have r.b.t. archives. He was definitely a proponent of them, preferred a specific brand/style, and would have easily been able to do the experiment.
The world is full of papers that are wrong. Including maybe the one this whole thread is about. It’s okay, it happens. Science doesn’t find right or wrong, though a lot of people think so. It finds more wrong and less wrong.
There's no a priori reason conservation of momentum would apply; for that matter in 0-angle-of-attack aviation it doesn't.
Maybe to put it differently, the "Newtonian" model of flight comes out of assuming CoM applies, which we know isn't universally true.
EDITING: of course it always "applies" in the sense that there is a definable system in which total momentum will be unchanged, the point being that there is no guarantee that's a system in which the plane gets lift greater than its weight
A symmetrical airfoil at zero angle of attack doesn't generate lift because it doesn't turn the fluid. A non symmetrical airfoil will generate lift even at zero AOA because air has viscosity and the lack of symmetry causes it to turn around the shape. When you bend fluid flow, COM comes into play.
My daughter did her research in this field while an undergrad, and explained to me that photosynthesis is not yet well understood. Some of the theories of the mechanism are discussed here: https://physicsworld.com/a/is-photosynthesis-quantum-ish/
Do we know whether the mechanism was proposed before or after observing the results? If they found the material because of the theory, then I think it's very relevant.
Lee and Kim first discovered the material in 1999 and have spent 20 years doing other things in between getting help to figure out how to isolate LK-99 and reproduce the correct grain structure.
They eventually got a world class physical chemist, Kwon.
There is now a huge bust up within the team, hence the muddled race to publish and claim credit.
Ahh that makes sense. I was wondering what was going on with the two papers and thought it might be something like that too. Thanks for the extra details.
Somewhat similar compounds are superconductors, so it's possible that a wrong theory gave them a lucky hint to modify an old superconductor into the new superconductor.
You might also say it's the only type of claim science recognizes. Though, whatever or how strong a claim is, the question is how important is what is proven and will it lead to real superconductive materials.
The strongest type of claim is when an a priori claim is called absurd, someone goes to make observations to disprove it and comes back convinced of your theory.
> I don't think the actual proposed superconductivity mechanism is the relevant part of this paper.
Plus even if the proposed-mechanism is incorrect and even if the effect is not strong enough for practical engineering... There's value in a "real" (if weak) superconductor which is both easy to fabricate and easy to run tests on.
It could become a starting-point for dozens of other tweaked formulations, enabling all sorts of not-so-expensive experiments and fresh data about how different parameters lead to different electromagnetic outcomes.
I’m not entirely sure that’s true. A posit in the paper is this is a novel super conducting mechanism and as such if the mechanism is true it’s totally unexplored. That leaves open a huge field of new research. That’s certainly a relevant part of the paper. Super conductivity at room temperature is an amazing breakthrough alone, but if it was with a clever tweak with an existing well established technique that would be the end of the story. The fact it’s an entirely new technique opens a world unexplored and indicates a pathway to even more amazing discoveries to be had (and funding for entire generations of physicists).
>I don't think the actual proposed superconductivity mechanism is the relevant part of this paper. It is much easier to prove that this is superconducting than to prove why.
As another commenter has pointed out, the proposal of a new mechanism seems to be extraordinary and novel, and could lead to an explosion of new research, so it does indeed seem to be "relevant" on its merits.
I also don't see this as a case of the "why" being left unexplained. In the history of superconducting it has indeed been the case that new cocktails have led to superconductivity without the underlying why being understood. But the commenter that you're responding to quotes part of the paper that shows an awfully specific mechanism.
I understand the sense in which there can be a "why" that remains to be explained in certain circumstances, even when you have a mechanism. Who do monarch butterflies have the black and orange pattern on their wings? There's a cause and effect answer but there's also a "why" answer. But with superconductivity, the mechanism is the why, unless I'm misunderstanding here. If other forms of superconductivity rely on other mechanisms, there isn't going to be a general why connecting this case to the other cases, but nor is there anything left unexplained just by explaining the "why" of this case by explaining it's extraordinary mechanism.
> They propose that electron tunneling between these quantum wells, which are between 3.7 and 6.5 Ångstroms apart, is the superconducting mechanism.
That is a very strange explanation. As someone who has done a decent amount of solid-state physics work, I would expect the explanation to involve a mechanism for pairing of electrons. Mere tunneling between quantum wells has been a staple since the "metamaterials" of the 80s and 90s.
That said, the measured curves do not lie, and I haven't kept up with the field. So I'm all ears (and very much hoping the superconducting revolution is upon us!)
> sudden resistivity changes at a critical temperature (bizarrely high though that is in this case)
How high? Just wondering if it might eventually be possible to use it in some power/clocking distribution layers of a semiconductor chip without bulky cooling.
That's a good idea. Honestly, I find it pretty amazing that modern CPUs don't just instantly turn into a puddle of molten metal as soon as you turn them on.
The critical temperature is 127 C, as the other commenter mentioned. That seems like it's high enough to be useful in a computer CPU.
I suppose there might also be applications for power distribution in a data center. You might use a few large, high-efficiency low voltage DC power supplies to supply the whole site instead of hundreds or thousands of individual power supplies if electrical resistance in cables was less of an issue. (I think this sort of thing is done now, but more at the rack level, since long cable runs cause losses.) You might even use 1V power instead of 5V or 12V.
(Granted, superconducting materials don't have unlimited current capacity, and bad things happen if you exceed the limit.)
The critical temperature is not 127 C. They did not actually measure the critical temperature. They just said it's at least 400 K (~127 C), probably because that was the maximum temperature the equipment they used could measure.
> Just wondering if it might eventually be possible to use it in some power/clocking distribution layers of a semiconductor chip
There's an additional obstacle factor here which is that the material has to (a) be "sputterable" onto the surface, which may rule out things with fancy crystal requirements, and (b) not adversely react with the rest of the chip, which is why coppper is ruled out (!) and chips use aluminium for metal layers.
Copper replaced aluminum some time ago (starting ~1997) regardless because of the resistivity, and they just had to find different barrier materials to prevent electromigration and overcome other issues.
Live to see SPARC turn on, there are some pretty smart people with models actually showing it breaking Q>3. Turns out the hardest part about productive fusion is the sustained high compression, and HTC tape really helps increase the compression by a large amount. (See their 20 Tesla test at the start of the pandemic)
Just want to mention for others: The first result for SPARC on google is SPARC (Scalable Processor Architecture), whereas SPARC (tokamak) [1] is what relates to Q>3.
It would be great though if they stopped sponsoring the war in Ukraine. Yes it's unfortunate that their main HTS tape supplier is Russian, but pretending that it's not and just ignoring the issue (or obscuring the supply chain through that Japanese middleman) is pretty immoral.
Meanwhile as someone who had to deal with writing code for Solaris and using Sun's compiler, I think I've achieved my goal by seeing my last SPARC turn _off_!
What do the "super forecasters" have to say about this? Was this predicted on prediction markets? Was the assumption of this tech existing already factored into prediction models?
This video (https://sciencecast.org/casts/suc384jly50n) showing the Meissner effect should be the easiest to replicate: just send a sample to another lab and put it over a large magnet.
As far as I know, the only explanations for this occurring is room temp superconductivity, or a strong diamagnetism (which would also be very cool to see)!
I don’t know enough about this but shouldn’t the entire superconductor be floating above the magnet? Why is one part still attached (or maybe attracted) to the magnet?
A strange exposition video then, I would try to remove the part that wasn’t superconducting (the part touching the magnet) before I released this. A completely floating piece of this superconductor would remove literally all doubt.
Scope of the claim. This is world changing. Shoot the first video, then get the dremel/pliers and cut that large bit off. It would be worth it, because if this works at all, then it's vital to prove it. We'd be having a very different discussion if that small piece was umabiguously floating and remaining locked in place.
For one thing, because if you're throwing out a world-changing claim, you yourself would like to be sure it is what you think it is.
It's an obvious test to do, so it's quite surprising they didn't do it. Maybe they did and didn't film it, I don't know - but for the trouble of a couple of minutes of time, it's weird not to have it - especially if your method is reproducible.
Based on what I'm hearing, it sounds like they weren't able to produce a macroscopic ingot of the stuff, so it seems likely to me that the superconducting part is up at the end there. However, without further explanation, I'm disinclined to take that video (fantastic as it seems) to be conclusive evidence of anything.
The original preprint mentions bulk samples, but I’m not sure what size they were. I would guess at least a few millimeters scale, but really bulk just mostly means “not a thin film”
As an undergrad I helped with research on quasars, where reasonable precision was solar mass orders of magnitude and tens of parsecs, and the periodic table was Hydrogen, Helium, and "metals". Then I switched to condensed matter physics for grad school, where "bulk" meant "a scale visible to the naked eye under very good conditions".
The common point being that it levitates, at room temperature (so no cryogenic fumes on the video), but that's exactly what you'd expect from a room-temperature SC… The big difference between your graphite video and the one from yesterday is that the later doesn't move, whereas the former never rests.
The problem with the video we see is that the sample never actually levitates - one side is touching the magnet. So a regular diamagnetic material, with enough weight on one side, would display the same effect.
In this video shortly after this moment you see something very similar looking with pyrolytic carbon: https://youtu.be/VC3r9-OaWes?t=133
It's true that pyrolytic graphite does this, but it's also worth noting that pyrolytic graphite is one of a very few materials that has such a strong conventional diamagnetism: the list includes pyrolytic graphite and metallic bismuth and ends there. I have actually searched the literature for such materials on a few occasions simply because they seem like they would make a fun decoration, and PG (and "highly oriented" PG) is pretty much the only one (bismuth is too dense).
Definitely. Discovering another material besides pyrolytic graphite that exhibits strong enough diamagnetism to levitate wouldn't get your name in the history books like room-temperature superconductivity would, but it would already be a major career-making discovery, with at least enough commercial value to launch a niche company. It would be very strange to tarnish your reputation with fraudulent, easily-refuted claims of superconductivity if you've already achieved such a breakthrough.
As far as I am aware you need multiple magnets to make this happen, just one will cause it to "fall" off. In the video it's just one magnet, and it doesn't try to "slide" away when it's moved past the edge of the magnet. That's a strong indicator of quantum locking.
They don't show the actual field of the big metallic cylinder, so you can't rule out a situation as shown at the start of this video: https://youtu.be/D-tW8_SRW3g
where two identically looking objects are revealed to have very different magnetic fields.
Whether it makes sense to say the multipole magnet is "multiple magnets" is a philosophical debate in itself.
"Who knows what could come out of that? Robust high-current-density room-temperature superconductors are right out of science fiction (SF readers will recall that one such material was a big plot point in Larry Niven’s Ringworld). Electrical generation and transmission, antennas, power storage, magnet applications (including things like fusion power plants), electric motors and basically everything that runs on electricity would be affected. We could stop throwing away so much generated power on heating up the wires that deliver it, for starters."
Nuclear fusion much easier, quantum computing, lossless electricity transmission, insane batteries. Dirt cheap MRIs, Basically welcome to the Jetsons. Much easier to mitigate climate change to the point where we can just deal with it.
Battery grid storage would be dead in the water, as we already use Superconducting Magnetic Energy Storage for grid stability and ultra-clean power in certain industries - except suddenly a huge chunk of issues involved in making large power SMES will disappear.
They won't replace portable batteries soon, but room temperature superconducting will greatly increase efficiency in all areas of electricity, including higher power motors (the efficiency gains are good enough that superconducting motors and generators have been attempted despite needing supercooling). Also, a simple SMES could easily buffer future BEV truck charging station despite projected 1MW connection per charging truck.
The challenge of fusion is a collection minor problems that add up to machines that are unviable for our current level of industrial output. Eliminating one of the three key plant systems (cryo, vacuum, and heating) is not a molehill, especially when it is the second highest user of power (after heating).
Room temperature superconductivity does not help with quantum computing. The transmons or atoms or ions need to be cold so that they do not get "flipped", not because of the need for superconductors.
Do quantum computers not have a need for strong magnetic fields? Or is the magnetic field requirement weak enough that it can be serviced by non-superconducting magnets?
How would this make climate change easier to deal with? Because it would make everything that much more efficient? I'm honestly trying to understand the implications.
Long distance power transmission suffers losses from resistance. Superconductors don't suffer losses. With superconductors you could stick a giant wind farm in the ocean and cover the Sahara in solar panels. Run distribution lines from there to everywhere else and pretty much call it a day on the planet's power needs. (lots of things glossed over, not the least of which are social and geopolitical but you get the idea)
Lead is used in many places. You should avoid checking what battery is in your ICE vehicle.
What matters is how lead is handled. With hope, mankind will never lead a generation the way burning millions of gallons of leaded fuel did. Certainly no use of a lead superconductor could hope to accomplish that level of damage.
Not necessarily. The "strained crystal" approach probably extends to other elements; mixing Pb and Cu works well since there's a large difference in their sizes, but rare earths might work just as well as Pb.
While we’re waiting for experimenters to reproduce this, it’s worth comparing this amazing announcement to the Cold Fusion affair of 1989[1]
It’s notable that the first publications about attempts to reproduce the Cold Fusion experiment all reported positive results.
It’s probably because experimenters who got negative results decided they might have done something wrong so they kept trying, and delayed, and they did not publish until later.
Those early reports of positive results were largely retracted within a few weeks.
Small effect sizes make it easy to confuse noise for positive results. Throw into it the very strong desire to see the thing work, and, well, even the best of us are only human.
It was a great blog, it was a lot of fun when I found it.
The summary was basically that, designing a reliable calorimetry equipment and experiment suitable for use in Fleischmann-like experiments is just uniquely challenging, it remained an unsolved problem even decades after the initial fiasco. The whole experiment setup is inherently error-prone. I found it was pretty interesting.
One researcher P.J. King who recently attempted a replication [1] commented online [2] that:
> We observed the claimed heat effect, both in magnitude and duration, in our parallel __control__ cells. This indicates a calibration error in the apparatus. One little known fact about these electro-chemical cell experiments is that they are run for a week or more before the effect is observed. Typically, calibration is conducted over a few hours and is done both before an experimental run and intermittently during it, to re-check thermal stability.
> We submit that this approach to calibration is inadequate for establishing a calorimeter’s propensity for heat artifacts. Stability over time periods longer than the experiment should be demonstrated in order to minimize the possibility of misinterpreting the fluctuations that we observed as “excess heat” events.
> Consequently, we contend that all claims of anomalous heat in LENR experiments using electro-chemical cells that do not exhibit thermal stability on a time period longer than the time duration of the experiment itself must be thrown out. As the majority of research over the past 30 years has not demonstrated this kind of calibration stability, that eliminates most of the effort in this field. You can read more about our work on the ReResearch LLC website.
> That is not to say that we know everything about hot fusion in the solid state or how quantum mechanical interactions might impact fusion reactivity. There is much still to be discovered. But these electro-chemical LENR heat experiments are noise, not signal.
[1] Guffey, Mason J., Yang Tang, and P.J. King. 2016. “Attempted Replication of Excess Heat in the Letts Dual-Laser Experiment.” Journal of Condensed Matter Nuclear Science 20 (1): 1–28.
IIRC, there were two groups of groups working on it (the process was simple enough that a description from the press conference was enough to get started):
* people looking for fusion neutrons, who did not have much experience with the finickiness of neutron detectors and who reported seeing them when they were getting experimental errors, and
* people looking for excess heat, which was simply inherently difficult to measure accurately.
On the other hand, there wasn't a publication delay for the negative reports; within a week the groups started talking to each other and realized they weren't unique in not finding anything.
The experiments with the e-cat were measuring temperatures and estimating heat flow of the hot air flowing arround the device. That's too difficult to do acurately.
If you see a report of a groundbreaking experiment that only measure the heat of the air, you can safely press the "meh" button.
Another example of this was Millikan's determination of the fundamental electric charge (of one electron). The first, famous experiment had a major error; and subsequently everyone who independently replicated the experiment, for two decades, came up with the same error, in the same direction. The people whose experiments got the correct value probably self-selected themselves out of publishing it.
Room-temperature superconductors have so many urgent commercial uses that if this fake, I doubt the error will persist for that long. There's too much at stake.
There's also probably a hundred labs skipping over replication completely to try and beat someone else out on a random permutation of these materials and methods and hoping to get lucky.
Yes, "replication" in this experiments usualy means foloeing the oficial recipe and many small variants.
Publishing an exact reproduction is difficult, but a new record a few degrees hotter is easy. (And even another variant with a lower temperature and more tolerance for current or magnetic field can be published with the right text.)
I can't see why they'd skip replication given the uncertain status of the original process. They'd try to replicate as closely as possible, confirm they have a superconducting material, then they'd branch out from their established process. Starting from a variation means they don't know whether it doesn't work because of the variation or because it doesn't work at all.
That’s not unreasonable, but the high-risk, high-reward approach would be to let researchers elsewhere do basic verification, while you try to leap a step ahead of them by going directly to derivative variations.
Abandon the work if nobody can replicate LK-99 within a few weeks and you haven’t really lost out badly.
It is interesting to note that while the error was in the same direction, the magnitude of the error decreased in subsequent studies. No one expects to get exactly the same result, so there was room for variation towards the true result.
The guys at Falcon Space said they were working on trying to reproduce it today - they said they have everything they need.
This is their channel https://www.youtube.com/@FalconSpace where you can learn more about them
Also, on the sentences in the manuscripts trying to explain the effect: I think that is wild guess at best. The measurement results done in the manuscripts probably can be taken at at face value (at least until there is a reproduction). Whether they really indicate superconductivity or something else that looks like it in some of the aspects is then a different question.
Nitter is an alternative front-end that allow you to view the tweet and the response while Twitter only only to view the attached tweet only. So in fact , it's better that he used nitter rather than the "original"
Twitter is not a publicly available resource, not part of the open web: Its URLs are semi-private and require an account to fully read and they should not be posted here on HN.
For almost two weeks they were fully locked, and now one can only see the original post and not the thread, and all browsing is locked out.
TFA notes that it should be quick to replicate and it's definitely gotten enough attention. If the right lab has the needed materials readily available, I expect we'll start seeing credible people posting excited tweets implying initial confirmation as soon as Friday afternoon/evening (assuming it replicates on the first go). If we don't see anything by the end of next week I'd guess that either it's not replicating or, at minimum, it's more finicky than it first appears.
Slightly more pessimistic than I was expecting given the amount of hype this has generated. Though I guess for something this groundbreaking a 25% chance that it's real is pretty newsworthy.
Researcher on reddit thinks it's probably spurious measurement artifacts, not superconductivity:
> I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, they do not have scientific knowledge of the background theory. In review of these two papers, it’s terrible science, not something malicious (as has been seen before in RT superconductivity work…). Even if these claims turn out to be true, it's still terrible science, and that's my main criticism. Either way, these types of claims are not uncommon, see for example this paper from a few years ago which went nowhere. https://doi.org/10.48550/arXiv.1807.08572
> So, to clarify for my nonexpert brain, if this were a superconductor and their measurements were accurate:
> Fig 5 means the sample must be completely pure to be a superconductor
> The rest of the paper indicates the sample must have impurities.
> So it's pretty safe to say that either it's not a superconductor or their measurements are wrong (or most likely both). Since they never got it to the critical temperature and showed the full Meissner effect, if the measurements are wrong it's fair to say they don't have evidence for superconductivity anyway, just diamagnetism, which isn't really that big a deal
In any case, the need for impurities would not itself surprise. Having controlled amounts of impurities is called "doping", it is well-known from studying semiconductors and other high temperature superconductors that the amount of doping can have a huge impact on a substance's properties.
He doesn't provide an actual counterargument,he just says he doesn't like the data without explaining why.
His earlier comment that graphite can do the same thing is untrue afaict. Graphite can repel the magnetic field but it would slide off, this is why in diamagnetic experiments multiple magnets are used to keep it in place. In the video it doesnt seem to be sliding anywhere, so imo the video is not showing diamagnetism.
Edit: Actually, now I'm not so sure, it does seem like it's held in place by one corner which is always pointing towards the outside of the magnet, so maybe it is just diamagnetism. If anyone has some pyrolytic carbon and wants to try it out?
Edit2: 99% of YouTube videos on diamagnetism have multiple magnets, the only one I could find that has diamagnetism on one pole magnets shows it not working:
It is clearly resting on the magnet. I don't know the mechanics off the top of my head, but that is enough mechanical constraint for a pair of permanent magnets to levitate.
Superdiamagnetism occurs primarily in superconductors.
Reminder that flux-pinned levitation only occurs when superconductors are cooled from above to below their critical temperature while in a local magnetic field.
The researchers probably didn’t heat up their big sample above the critical temperature in air as that could have mechanically destroyed it. It was already chipped almost in two.
> Reminder that flux-pinned levitation only occurs when superconductors are cooled from above to below their critical temperature while in a local magnetic field.
Casual demonstrations of levitating superconductors involve first submerging the superconducting material in a (non-magnetized) tub of LN2, and then moving it onto a magnetic track. For example, https://www.youtube.com/watch?v=X5EoUD-BIss
I’m not convinced it’s levitating in the video, imagine a magnetic field strong enough to partially lift the fleck but also a patch of the fleck contacting the magnet with enough friction to keep it from sliding away.
> However, only one edge of the flat, coin-like material fully levitates, while the other seems to stay in contact with the magnet. Kim says this is due to the sample being imperfect, which means that only some part of it becomes superconductive and exhibits the Meissner effect.
I'm not a materials scientist but an electronics guy.
> 1b) shows the resistivity at some unknown temperature. They are applying current and measuring no potential drop. Just what? First, state the temperature, next measure it as a function of temperature. At the critical temperature the resistance drops to zero. All they have shown is that the contact inputting the current is probably disconnected…
this does not pass the sniff test for me. I explained on reddit myself why I think it doesn't make sense.
The only way that could work is if they just straight up fabricated everything, and in that case all bets are off.
I can't comment about the others since I don't know enough about it. Considering 1b) makes no sense with a modicum of knowledge, I really doubt the veracity of the rest.
You realise two of the authors (Lee and Kim) discovered this in 1999 (hence LK-99), and only published this paper after a huge fall out within the research team?
This isn't 1 experiment. This is 20 years of research leaking because of a fight over credit.
>> they do not have scientific knowledge of the background theory
One of the co-authors of the 6-author-paper, Hyun-Tak Kim, is at least answering questions about superconductor theory on Quora starting five years ago, whatever that counts for.
He states there "I am studying the MIT mechanism in strongly correlated systems, the high-Tc mechanism in cuprate superconductors, the MIT devices, and quantum transistors.".
In the first paper, they claim to measure zero resistance (on a scale of microvolts), but are very careful not to show full RvT curves - in the second paper, we can still see significant changes below Tc where they include more complete curves. How can the resistance change significantly in the superconducting (zero resistance) state? We can actually see significant noise in paper 1 fig. 1c in the ohmic state and it even appears to behave as an insulator at 0 field (increasing resistance with decreasing temperature), but a metal with applied field. There's something wrong with the measurement.
400 K is an odd choice for your superconducting temperature, and just so happens to be the top end of what an MPMS system can measure so is not completely random. Surely it makes sense to measure significantly above this with one of the oven attachments, verify these results with collaborators at other labs even.
10 Gauss is an extremely small field to use for a ZFC-FC measurement and again if their superconducting Tc is at or above 400K they need higher temperature data to show anything about the phase transition.
The claim that they have measured the density of states is completely unjustified - not even a citation. I don't know how you can believe that to be the case.
And in general the presentation both of the data and the paper itself is poor - if you just made a groundbreaking discovery like this, wouldn't you care?
> if you just made a groundbreaking discovery like this, wouldn't you care?
Hell no! If I had made a discovery of similar magnitude I would have done exactly what they’ve done: push out a rough preprint ASAP to reserve my Nobel prize, then take a deep breath, relax and take my time dotting ‘i’s and crossing ‘t’s for the real paper in Nature.
That doesn’t mean they’re correct, but there’s nothing inherently suspicious about the way this has unfolded.
Exactly, they have made a very big claim and made it very easy to replicate / falsify. It takes a few days to produce this stuff.
Their paper is weak on data / results.
This is exactly what you would do if your team genuinely believed you had discovered something monumental.
In poker terms they are "all in" and they want to get called.
That's why it is so interesting. If they had posted lots of extreme results but it needed $10m to replicate then I would be thinking "fraud". It would look like a bluff.
As I mentioned in my above post, they have really dodgy data. Ideally, with something like this, you would have collaborators to verify alongside you as joint co-authors. I think something people underestimate if how easy to replicate samples are - crystal growth is difficult, and impurities are important. It is unlikely anyone will produce exactly the same sample only something close based on the process they've given.
In realistic terms it seems they're grabbing for the prestige without the foundation of crossing their ts. Bad science like this shouldn't be encouraged. It's likely there's not very many groups growing the same material system so they have the time to spare. A paper like this wouldn't be on the arxiv at all if they were 100% sure because they would go straight for the nature publication and take the time to do more follow-up papers while they can.
Edit: to be clear as well, a lot of people are underestimating the time it takes to reproduce a growth even with a manuscript telling you how to do it. People always leave out steps and oversimplify. There is a lot of extra characterization that takes time to double check you have the right material that lines up with what they have here. Only the direct competitors actually already growing this material can do it in a few days.
From what I understand, this group wasn't actually funded to look for superconductors but instead for materials to aid in quantum nanoscience - so the claim isn't that they don't know how to read their instruments but rather that they aren't well-versed enough in superconductor research to appropriately design/test for the phenomenon.
What do you mean? Is it one of the other papers? I see this:
Funding: This research was mainly supported by Quantum Energy Research Centre, Inc. and was also partially supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education(2019R111A1A01059675) and Young-Wan Kwon is supported by a Korea University Grant.
I don't know, either: what's the difference between receiving funding for research and taking investment money for it? Are you talking about public vs private funding?
As far as I understand there is no real explanation for the measurements and the video demonstrating the Meissner effect apart from faking it.
The Reddit thread that you posted alleges that they were faking the video by super-cooling a non-room temperature superconductor for example.
Do you have proof that they actually are so crazy to fake a certain Nobel prize when their research can be verified in a short time?
From my side I will wait a week or two for the reproduction from other labs. You can continue spreading your reddit-based opinions until then.
All the amateur debunking just smells like the usual confidently incorrect contrarianism, which is always popular on sites like Reddit.
There's just way too much going on for this to be a sloppy mistake. It's either real or a fraud, and in both cases the alleged errors aren't particularly important.
I’m reminded of the paper, just over 10 years ago, that reporting measuring neutrinos travelling faster than the speed of light.
When published, the authors made it clear: this is probably wrong, but we can’t see where we made a mistake … so what if we’re right and just upended relativity theory?
That was turned out to be a measuring error [1]. This one may be the same, though the lead authors publishing two versions of the paper - one with only 3 names, ostensibly because the Nobel Prize can only be awarded to a maximum of 3 people - suggests less modesty and vulnerability on their behalf.
I don't see the similarities. This upends zero theories. I see similarities in the long line of "STP superconductors for real this time!" claims, but not findings that contradict current physical models.
I thought of that too, but the difference is that faster than light travel is impossible according to our understanding of physics, but nothing says that room temperature superconductors are impossible.
>Kim has only co-authored one of the arXiv papers, while the other is authored by his colleagues at the Quantum Energy Research Centre in South Korea, some of whom also applied for a patent on LK-99 in August 2022.
>Both papers present similar measurements, however Kim says that the second paper contains “many defects” and was uploaded to arXiv without his permission. In that paper, the work is described as opening a “new era for humankind”.
>Other experts that New Scientist consulted were similarly sceptical about the results and the data produced. Some raised concern that some of the results could be explained by errors in experimental procedure combined with imperfections in the LK-99 sample.
I’m not a physicist expert of superconductors, although I’ve followed quite closely that field since the ‘90s.
But if the measurements are similar and correct and if the video of lk-99 levitating above a magnet demonstrating the Meissner effect is not fake, I don’t really have an alternative explanation to account for all of that.
I guess that we’ll see what happens in the next week or two.
This is too high stakes to take longer than that for a so easily reproducible experiment.
It has been proposed that alternative mechanisms besides SC can create diamagnetic effects. I think we're waiting on more informed updates because the people with the competence to comment on this are probably working furiously in a lab right now rather than commenting.
edit: useful comment elsethread by macromaniac on plausibility of diamagnetic effects
If true, it seems wild to sit on this kind of discovery for over two years.
Update: Seems like there might be even more history given the name LK-99 apparently comes from the names of its discoverers Dr. Lee and Dr. Kim, and the year of its discovery, 1999 (https://kr.linkedin.com/in/ji-hoon-kim-03508b80).
Naive question: is that the original content of the application from 2021, or could it have been updated later? Is it the same material as LK-99 in the published paper?
quick googling appears to indicate that it was produced in trace amounts as a consequence of other experiments at that time and only was investigated in and of itself in larger amounts more recently? Awaiting more info from better informed people.
Is that, "I never meant to publish this," or is that, "It was a rough draft that I hadn't edited for accuracy or tone and fuck Steve for uploading it."
I’m guessing the second. Nothing in the interview suggests that he doesn’t stand behind the data. Sounds like he’s taking a wait and see approach and it’s a very good sign that he’s offering to help other researchers try to replicate
I really think this could be in-fighting for the third Nobel prize spot (if it turns out to be legitimate). I pointed this out in another comment, but the first two authors are the the LK-99 material namesake and will likely always be the first two authors.
"YW Kwon" published the first paper with himself as the 3rd author, and "HT Kim" published the second paper a few hours later with himself as the 3rd author.
Pretty interesting drama if that's the case. May indicate neither paper was ready, but that they all think the result is legitimate.
"this stuff is claimed to superconduct all the way up to room temperature and indeed up past the boiling point of water. Its critical temperature is said to be 127C"
Would this have implications about possible efficient methods of converting heat back into electricity? Or even just more ways of harnessing heat energy in general. I'm imagining heat pumps built with superconductors could be a critical part of mitigating climate change, but I'm far from a scientist and barely understand the physics here.
No, it just means that the material conducts electricity without losing almost any energy through heat at that critical temperature. Heat itself is a process of energy transfer (heat itself is not energy which many people fail to recognize if they haven't studied thermodynamics thoroughly).
I see a few comments saying this can also be used to "solve" climate change, but I am trying to understand the how. Do people mean that the world will have less carbon footprint overall because everything will be much more efficient?
You build a big inductor, and because it's superconducting current just goes round and round. At room temperature you have no refrigeration losses, you can build more just as fast as you can kick out superconductor. It would be 100% efficient, have 0 self-discharge, and enormous power capacity and infinite power cycles.
I think it may be that electrical power could be generated in places where (carbon free) energy production can be abundant but consumption is low (e.g. Solar power in the Sahara desert) and then transported with almost no losses to sites of high energy consumption (e.g. the cities of North Africa and Europe).
North America could be powered with a small section of Nevada being covered in Solar Panels, given a theoretical transmission loss of only a few percent from one side of the country to the next. Bolster that with windmills and hydroelectric and that would be that for the next 30 years.
Electricity would be cheaper and more plentiful than water in many areas.
Even if we replaced all fossil fuels overnight we still wouldn't have "solved" climate change--the damage we have done is locked in for the long term. We need active mitigation to restore Arctic ice, de-acidify the oceans, save coral reefs, bring back old weather patterns, etc.
Raise your hand if you contacted Aldritch about the two pre-cursor materials :-)
This is an excellent summary and like Derek I have high hopes (but low expectations) that by the end of this week we'll see some tentative confirmation. This stuff isn't particularly hard (or expensive!) to make so that should really make for interesting news and some very fun products if it is proven out.
Good luck with your samples and in the very least it should be good fun to play a small part in the replication of results. If documented well enough you might even wind up in a meta-study some day.
The bigger the impact the more of a splash it will make in social contexts consequently we see a lot of blatant and cautious naysayers with various explanations and individual explanations for the logic of their refutation.
But it’s If it’s shocking enough, groundbreaking enough, anyone with the expertise to try will do so either to see if it’s right instead of waiting around for someone else to do it and write it up and publish it, or to prove that it’s not and for something this big at least, give BobbyBrocolli a new possible video topic to consider.
500 comments
[ 2.9 ms ] story [ 307 ms ] threadGerman, but nevertheless: http://blog.fefe.de/?ts=9a3f8740
"I work in the field [...] we don't believe a word of this. [...] The data set in Fig. 4(b) is also a treat. It is VERY unusual when the heat capacity decreases again at high temperatures. This can happen at low temperatures, but not at high temperatures. [...] My personal assumption is that the authors measured an insulator, so no current flow and therefore no voltage occurred (4-point measurement). This would look like a superconductor. But if you then turn up the current (i.e. the applied voltage), breakdowns may occur and a current begins to flow. That would explain the sharp increase."
This isn't 1 experiment as the Germans seem to think. There are multiple papers, patents, etc.
The main focus of these papers has been to make huge claims and make replication very easy. They are "all in" and they want others to call.
If they were bluffing they would be heavy on results and light/secretive on how to make the stuff (trade secret, etc).
That's why there are 2x papers published within 3 hours, both with different authors, and you have one author telling New Scientist he did not approve of a paper naming him as an author.
That might be your interpretation of it. I think the Germans would call it being straightforward.
But the papers don’t show that. There’s no obvious contradiction unless you make some big assumptions.
A more plausible idea IMO is that it could be a 4-point measurement of a highly inhomogeneous sample. If the current probes make contact with conductive parts of the sample, and there is a conductive path between them, but one or both voltage probes are not contacting the conductive path, then the voltage measurement would be garbage and potentially zero.
I don’t think this is much of a problem when measuring conventional conductors (you don’t need a particularly good contact, which is much of the point), but a lot of superconductors are oddball materials where, under conditions where they fail to superconduct, they barely conduct at all.
So maybe the sample has a conducting phase and an insulating phase?
I know they were formed from sulfur compounds, but the production process should have eliminated those compounds, and the final forming is done in a vacuum so there shouldn't be any oxide generation to form non-conductive barriers.
I don't know much about the process but shouldn't they be testing resistance in a superconductor?
https://www.oxfordlearnersdictionaries.com/definition/englis...
And we very much are talking about an alloy, which is a "metallic substance composed of two or more elements"
https://www.britannica.com/technology/alloy
Lead is a metal. Copper is a metal, a combination of 2 metals is an alloy.
However, you are right, I did overlook that the compound is an oxide, my bad.
"I work in the field and we discussed the preprint a bit in the research group this morning. In a nutshell, we don't believe a word of it:
What the authors might mean is that they are outside the Meissner range, which can occur at higher magnetic fields (keyword: Type II superconductors). This then looks like this.But in this case the temperature dependence does not agree at all with the critical currents of Fig. 1(a) and (c).
And also that ALL values in Fig. 1(d) are negative is extremely unusual, but this could perhaps be argued.
I don't think, at least generally, work is as rigid as indicated. At least at white collar jobs, and especially a research lab, and most especially a university research lab.
From the linked article:
> You can bet that furnaces in solid-state materials labs around the world have been cooking yesterday and today to try to reproduce its synthesis and the properties, and we should be hearing about the results of these experiments very soon. The first samples should be coming out of the quartz vessels. . .sometime tomorrow, perhaps? Depends on what was available around the lab!
It's impossible that at least some people didn't drop everything to try it.
If it is false we may never get a final report, just everyone gives up on reproducing it. (though with the hype we may see it like cold fusion were a few not very good researchers keep it alive via badly done experiments).
Only time will tell.
If someone claimed to have a complex proof, i dont think people would stop and drop everything.
If someone claimed to have a constructive solution to p=np, claimed to have implemented it, and put the code on github - yeah i think lots of people would drop everything to run it and see if it works.
Im not a physicist, but maybe with the relative ease on making this material (according to other comments) it is more like the second situation.
At this point assisting anybody who wants to help prove him correct (and I know that I’m making the assumption that he genuinely believes he has made what he claims in the paper with the mechanisms and methodology as outlined) will just help secure get rich faster and make his Nobel prize even more secure.
Polycrystaline materials are kinda finicky so more samples helps eliminate the error bars. So obviously why didn’t they do heaps of samples and have a longer paper? … Money! They got funding for quantum physics based sensor/detector research and this appears to have been a happy accident, so naturally they kept their heads down, got their patents (they have multiple patents each of which costs money) and did a little bit more work to be absolutely sure, then as soon as it was smart, they published their results and are now going to let the entire world excitedly double check their results… because the results if true, are fucking awesome…
Of course the world wants to replicate this, no one wants to be waiting for someone else to confirm a breakthrough this big… I bet there’s even some corporate labs doing a little work on replication too, so some smart managers in various industries can factor room temperature superconducting materials into their designs and future plans sooner, because otherwise their competitors might be! (Obviously there’s not going to be a lot of this since most companies don’t have internal science groups but the Lockheed-Martins of the world, the Daewoos, the Mitsubishi Heavy Industries, the Ratheons … I’d be surprised if they didn’t already have someone somewhere in the world who is still currently making batches and putting them into furnaces because the material is cheap and you can get a lot more certainty from additional samples if your are prepared to pay for the work. I’d be dammed sure someone at General Dynamics is making some because it would massively help them convince the US Navy to give them more funding to continue work on railguns!
Whether people will stop what they are doing to verify it is literally a matter of people stopping what they are doing. University labs are usually quick on that.
I would have figured ATF. What drug can you synthesize with phosphorus? (EDIT: Apparently meth [1].)
[1] https://www.federalregister.gov/documents/2000/09/25/00-2455...
Scientists can move far quicker than you expect, and a positive or negative replication of this superconductor claim should be a very easy publication to grab. It would definitely be worth alloting a few weeks of grad student time to replicating this ASAP to get that publication.
That said, I remember reading about shockley having ideas about the transistor that he only fessed up to as his other more open collaborators started understanding the phenomenon.
Labs all over the world are dropping everything to replicate this. It's simple self interest.
It only takes 2-3 days and the people involved in the paper are credible.
If it's real, your lab would be at the forefront of the biggest revolution since the transistor. If it's real, there will be hundreds of papers on the topic by next year. Your lab could be the one to discover a variant that can carry more current, that could have patent on the material of the future power grid. The papers that provide the basics for how this works and the data that everyone will be using will get 100k+ citations in a few years. The PhD students that become experts in this will be in high demand everywhere.
I'd expect some lab out there to report a result by the end of the week. The synthesis really is super simple, just grinding powders together and baking in a furnace. Granted, the final product has to be baked under vacuum, but that's not super difficult to achieve. The authors sealed the material in a quartz tube and baked in a standard furnace.
South Korea has been waiting for a (real, STEM) Nobel prize for decades.
These guys will be worshipped as gods if they deliver
Ouch.
I’ll draw an analogy to the LLMs and diffusion models that have lately rocked the computer world. These things are straight up science fiction. I would have said computers would have never been capable of art and poetry. It was all fantasy until it was suddenly reality.
We’ll probably know if this can be replicated relatively soon. And if it can it will kick off a whole new branch of materials science and begin a multi-year race to commercialization.
We are facing gigantic challenges in energy and climate. We need the win, so my fingers are crossed.
Academics (and similarly venture startup founders) like to sort of jump to conclusions along the lines of “discovery was the hardest part - now this thing could enable ... in the next X years” at the end of a paper. And then people spend many decades to actually reduce this to practice. So 90% of work belongs to applications, not technology in on itself.
1.2 years ago if you claimed that an AI will just come out and make artists mass panic you would be laughed at. Now art is somehow just 'solved'. Progress is continuous and massive from Midjourney v1 -> v5
In other words, merely copying/reproducing something is emphatically not art.
The same thing happened with traditional (painting) art and photography - the latter didn’t really replace it but just supplanted it in the areas where one wasn’t really looking for art but for mere reproduction of reality. And then over time, photography itself has evolved into art, since people have learned how to channel their inner self through it, and aimed at quality instead of “quantity” (and unlike the former, the latter by itself became trivial). I don’t see the same happening with generative models quite yet (heck, they didn’t really replace photography either!)
psht, as if
And rightfully so. Humanity is moved by great people and these would be great people. We would build monuments to them to symbolize their importance.
North Korea: "We're still working on reliable electricity."
Alfred Nobel would probably find this characterization very ironic.
Or as the article talks about, is this just a pointer at other possibilities that would be the real game changers?
But the main one that is screaming at me for this technology sitting in front of us is SQUID sensors and RF antennas that will operate in the lower power range of the potential applications spectrum.
AFAIK loss at AC still occurs with superconductors because the dielectric loss through the materials still exists.
It could be a game changer for making efficient directional small receive antennas. Normally electrically small antennas are just super inefficient but it's made up for either on the transmit side (like with high power AM radio) or with most of the gain coming from some low noise amplifier (like small UHF wireless devices).
"Human sacrifice! Dogs and cats living together! Mass hysteria!” --Venkman
Not only products would be impacted but experiments too, particularly particle experiments. All colliders need some sort of ridiculous magnetic field which uses a close loop helium chiller.
Long term wise, anything that uses electromagnetic fields would be impacted, like motors and generators. You in theory can get stupidly efficient motors (99%+) motors with super conductors.
Wildly improved efficiency on some sensors, antenna, motors, etc.
- A global power net. No solar power during the night? Just produce it on the other side of the planet.
- A superconducting computer. Less resistance when pushing bits around = 500x less power consumption.
- A Superconducting magnetic battery. Store power indefinitely with high efficiency.
ETA: wrong
https://en.wikipedia.org/wiki/Superconducting_computing#Fund...
https://www.ti.com/lit/an/scaa035b/scaa035b.pdf
This document explains it well. (The resistance of the interconnect is not even mentioned as a significant component of power consumption.)
Obviously this isn't much benefit since the vast majority of applications can't be liquid nitrogen cooled (and computing has followed "what consumers will buy" on progress).
That changes substantially if superconductors will keep working when put in my pocket.
Assuming of course it is possible to shrink the superconductor circuits down to the same size of the semiconductor counterpart.
Whether or not we can manufacture/shrink the superconductor circuits enough to be competitive with semiconductors is another question, but my naive interpretation is that if you can make the superconductor circuits 100x larger than a silicon circuit, it is still going to have significant advantages.
This sounds like it has interesting ramifications for global politics. At the beginning of the Ukraine war, one major lever the Russian government had was to enable blackouts in Ukraine. Makes you wonder how a global power network could work in light of international conflict.
[0]https://en.wikipedia.org/wiki/SCMaglev
Near term may be useful for devices which take advantage of quantum effects such as Superconducting QUantum interference devices or SQUIDs.
Use in microelectronics may be possible, but is likely quite difficult. Making complicated structures out of this material will require radically new microelectronic manufacturing processes. HTSC microelectronics don't exist as far as I can tell.
If critical field can be improved things get interesting. If it can be increased to that of known HTSCs at liquid nitrogen temperatures(critical field scales with temperature), that's interesting because this material should be cheaper.
If it can be increased moderately at room temperature, there is the potential for it replacing rare earth magnets because the material should be cheaper.
FAA says even superconducting superdrones can't go over 400 feet.
But there is plenty of magnetic levitation right now without power:
https://www.amazon.com/dp/B01N2Z9QAP
also, balloons.
In general, the answer to this question is "no."
So, long distance electricity transmission, motors, generators, MRI machines and magnetic confinement nuclear fusion reactors for example.
That said, the material as synthesized might not be very good for some particular application. The current handling capacity might not be good enough, or it might not be physically strong enough to use as motor windings.
I don't know enough to do the comparison, but I'd be curious how this new material holds up when compared to copper or aluminum wire in terms of current capacity, weight, strength, and cost of materials. One of the big reasons for skepticism about humanity's prospects for converting to a non-fossil-fuel based energy system is that there just isn't enough of the important metal resources to build all the batteries/EVs/transmission lines/solar panels/windmills we need. I myself am skeptical of the skeptics because I think the resource bottlenecks are overstated and there are usually acceptable workarounds, but I do think copper is going to be in very high demand over then next several decades. If we have a good, cheap copper alternative then that solves that problem. (It also introduces another, as we would then have to deal with enormous quantities of lead-based cabling.)
Of course if you can make wire out of it, I wonder how much smaller your fusion reactor can get?
There are a lot of applications for even a thin film, consider spray coating a resonant cavity with it.
I'm sure there is a way to improve almost anything you could think about if you start talking about making CPUs with lower heat dissipation, perhaps enabling 3D designs and much more efficient computing... [edit: obviously there is a limit from literally the entropy in computing and transistors are most of that, I wonder if the superconductor is a good thermal conductor...]
I'm sure there are at least 222 startups that have some idea they're pitching right now ;-)
> The authors believe that the modified/strained structure of their material creates a large number of “quantum wells” between particular lead atoms and the adjacent oxygens of the phosphate groups bound to them, in effect making a two-dimensional “electron gas”. They propose that electron tunneling between these quantum wells, which are between 3.7 and 6.5 Ångstroms apart, is the superconducting mechanism. I am not enough of a solid-state physicist to judge this proposal, but the authors are making a detailed mechanistic claim that is subject to experimental proof, which is very good to see, and and they adduce a good deal of data to back it up (x-ray diffraction, EPR, and more). And they demonstrate the behaviors that a superconductor should have, such as the Meissner effect (expulsion of a magnetic field), sudden resistivity changes at a critical temperature (bizarrely high though that is in this case), current-voltage (I-V) plots at different temperatures and under different magnetic field strengths, etc. If these data reproduce, the superconductivity of this material seems beyond doubt.
Even better, it's a HUGE claim that is going to show how epistemology in science works (reproduction!!)
This only can carry a small amount of current. I'm not sure how to figure out what small means (numbers are given in the article if you know how to use them!), but if the losses using regular wire are less than the energy needed to make this stuff then it isn't useful.
This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical. Or it make leach lead into the real world making it not safe to deploy.
There are probably other ways this can turn into a "it works but isn't practical" thing that would force us to wait for theory (or luck!) to point to something better. What I wrote above is what I can think of in a couple minutes. Only time will tell though, I hope it works out.
Thank you for this.
> This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical.
Have you been to a hardware store lately? A huge amount of pipe fittings for gas and non-potable water are made from lead. Factories don’t find it hard to work with lead. It might be inadvisable but it’s not hard.
We can argue about the "working safely" part, but in terms of "does this make it impractical?" the answer seems to be no under the current global regulatory environment.
Sometimes you get arguments between partisans for each of these two simplified explanations, but really both are bogus.
It really isn’t that mysterious, unless you insist that only a single physical law is allowed to come into play.
That's orthogonal. Planes flying upside down still have air flowing faster over the new "top" of the wing than the bottom.
Though, a common misunderstanding is that air must be taking the same "time" to go over the top and the bottom. This is not true.
You can build a pretty good mental model of flight with either simplified mechanism, but you end up underestimating performance by a fair bit.
I've never hear of a good mental model built on Bernoulli's Principle. They are either:
- Wrong
- Give no intuition
The key question is /why/ air moves faster on one side, and once you get away from the misconception of same time, I've never heard an intuitive argument.
Redirecting air down:
- makes complete sense
- can be demonstrated by sticking your hand out the window of a car
- works with flat airfoils (sails, kites, etc.), and explains those well too
And the shape of the wing comes in from wanting the leading edge parallel to incoming airflow, and the other edge parallel to outgoing airflow. On a sail, I can adjust the shape. On a steel wing, I can't much, so I make a shape which works across different angles of attack.
All of the other mechanisms, you can gradually work in from there to get accurate models. Toss in air moving to the low-pressure area, and having momentum, and you get why helicopters are less efficient than planes, as well as vortex shedding. It all builds up.
As a corollary, Bernoulli tells you where air moves faster, but that follows from lift. Not the other way around. At least in any model which fits the human brain.
I'm sure models can accurately compute how much of the wing lift comes from the suction effect on the top of the wing versus the push on the bottom of the wing.
"You can build a pretty good mental model of flight with either simplified mechanism"
For computational models, neither of these are great starting points. When I last looked, finite element methods were where the action was.
And if you don't apply the same to quantum -- looking for intuition -- you'll have a bad time. Quantum computing algorithms came from human insight.
Since the air follows a curved surface instead of straight ahead, you could perhaps apply your intuition for centrifugal force. Momentum sort of pulls the air away from the surface.
I’m not even sure this explanation is wrong.
Counterpoint: A wing with the opposite curvature would work too, just much less efficiently. Your explanation has an element of truth, but an element of untruth. It'd take more analysis to tease them apart.
>"Composites are causally redundant. Believing in chairs is like believing that, while yes, the burning gas from my stove completely describes why the water in a pot boils, there’s ALSO a magical invisible substance called boil-o that comes out of my stove that does the same thing as the flame at the same time, and if there was no boil-o, the flame would warm the water just the same, but there IS boil-o... Chairs are no more real than boil-o. Composites over-determine what happens in the world."
Like your example with lift and fluid dynamics, simple explanations like "plane pushes air downwards" or "faster flow sucks the plane upwards" might be insufficient, but they're at least useful to the layman. It also reminds me of how Richard Feynman answered the question, "What is the feeling between 2 attracted magnets?" by explaining that it would be impossible to give a complete answer. Feynman pointed out that when you ask why two magnets attract each other, there are different levels of understanding depending on your background knowledge. For someone with no knowledge of physics, the simple explanation would be the existence of a magnetic force causing the attraction. However, delving deeper into the question raises complexities that can be challenging to explain.
Feynman highlighted the difficulty of answering "why" questions in general. Explaining magnetic attraction in terms of something else that we are more familiar with, like rubber bands, would be misleading and circular, as it ultimately comes down to electrical and magnetic forces. He acknowledged that some aspects of the natural world may need to be accepted as fundamental elements without a more profound explanation.
This is echoed in the Vsauce video, where defining boundaries and attempting to explain everything can lead to paradoxes and vagueness. The concept of "boil-o" illustrates how composites, like chairs, can over-determine what happens in the world and our own perception, making their actual explanation even more elusive.
Where are you getting this terrible information that we don't know how flight works? Have you ever talked to literally anyone who has worked in aeronautical engineering, or even studied the basics of fluid dynamics?
Yeah, didn't think so. ;)
Lead is still routinely used in many applications today, either in metallic form, from ICE car batteries, to fishing or hunting gear, or as chemical compound in different kinds of glass. And the same can be said about other heavy metals like Cadmium or Mercury. Industries also routinely work with much more nasty things than lead, so it really doesn't sound like a show-stopper.
Maybe a little bit. But I think it is more that it is a material with heavy atomic nuclei and high density, and thus effective at blocking radiation. And it is also relatively cheap.
They used to talk about using barium cement but it just can't compete, price-wise.
I think >80% of the current industrial use of lead is for batteries. It's probably still in the top ten most mined metals by dollar value and definitely by mass.
Aluminium, was so expensive until the Hall/(that other guy) process was developed, that it was used for jewellery [1].
Even today it's expensive and difficult to reduce Al ore to metal, which is a supply side problem.
[1]https://www.bellandbird.com/products/aluminum-bangle
The economy sort of has a "working capital" quantum of aluminium which also grows steadily from aluminium mining.
Lots of metals have very different and complex supply structures and thus completely different $$$ / volume curves for their supply.
Understanding the $$$ / volume curve of commodities is not something that is commonly considered when people try and predict the future. Mining a billion tonnes of Aluminium from an asteroid for example and safely landing it on Earth can never be profitable because the $$$ / volume curve for Aluminium is $0.00 at billion tonne volume.
We should figure that out! But we can definitely keep using all the applications until then. (Except for Tylenol, we keep learning how bad that stuff is)
EDIT: It won't let me post more, so here's the answers to responses.
For sure!
https://www.cbc.ca/news/science/science-of-cycling-still-mys...
http://www3.eng.cam.ac.uk/~hemh1/gyrobike.htm
https://www.newscientist.com/article/mg22730370-400-how-does...
It's a fun little fact. We know a ton about BUILDING bikes, which is a more useful tool anyway
That said, I'm guessing this one is well understood by experts, but more complex than someone would assume at first glance, and many who have some understanding likely have an incorrect or at least incomplete understanding of how balancing works.
It's such a banal thing to be so fascinating.
The smart phone is the culmination of understanding a million facts about materials sciences (applied and theoretical), some of which were obvious, some of which were non-obvious. Starting from a transistor you could see from across the room down to ones you can't even see with a magnifying glass.
I actually find the ice skate a better example than a bike. We have all the physics solved for bikes, it's a complicated system but so is everything in motion. Hence we assume a spherical cow for the sake of the problem.
But ice skates... Now that's a funky one. Why do ice skates works? Ice skates aren't sharp bladed, they actually have flats. Ice is not slippery, it's when something is on ice in between our shoes and the ice that cause it to be slippery. Some people think it's the localized pressure of the blade that causes ice to locally melt. Hard to really wrap your head around. But it works :)
Not sure how you meant that, but ice skates are sharp. Each edge of the blade is sharpened by grinding a hollow out of the center.
https://weekendwarriorshockey.com/how-sharp-should-my-skates...
This depends upon the question one is trying to answer. If one is trying to create a bicycle that can self balance, that involves considering different factors compared to trying to determine why certain injuries result in a person losing the ability to balance on a bicycle while others do not. Is the focus the bicycle or the human?
Maybe we don’t know how humans use the bicycle but we know how bicycles balance, we can write programs to balance them physically.
0: https://youtu.be/Ya7iacmVjUM
1: https://youtu.be/2Z67NkvXIF4
How a human is able to manipulate it is simply by using the force of gravity from shifting their weight(moving the center of gravity). However, the movement of the center of gravity has to be perpendicular to the wheels axle. The steeper the angle of attack the wheel has to the ground, there will need to be an exponential increase in distance to move the center of gravity. Once the wheel is parallel to the ground, there will be an undefined distance needed to move the center of gravity.
[*]https://ciechanow.ski/bicycle/
We know how they work. We might not have fully characterised the stability conditions, but that's not the same thing.
> You can write out the equations of motion for a bicycle
> there isn't some neat little equation that says exactly what each parameter change is going to do
I mean, if you have the equations you can see what each parameter is doing !
There are things we can characterize to any desired degree of accuracy but that e don't get cute little equations out of... and some of those things are so simple they've been staring you in the face since middle school and you just didn't ever notice their absence from your formula sheets.
This is not the exact same situation being described but it's a similar thing. Being able to put a complex system into a computer and arbitrarily manipulate it still doesn't mean we can extract some simple explanation.
On the other end of the scale, see all the AIs coming out. They're 100% computer artifacts with theoretically no mystery in them whatsoever... but they're just tables of billions of opaque numbers and doing anything with the numbers beyond just running them is amazingly difficult.
https://www.insaneclownpossemerch.com/collections/insane-clo...
Scientists Try To Teach ICP Fans How Fucking Magnets Work
https://metalinjection.net/av/scientists-teach-icp-fans-fuck...
if you want to test this take nearly all the pretension out of your spokes and sit on your bike. feel which ones are taught and which ones are completely loose. or just go to walmart. those bikes hardly have any pretension in their wheels.
https://berdspokes.com/pages/technology
Doesn’t change the answer. They’re still compressing. They’re just pretensioned.
There are two situations when you can push on a string. One is when it’s frozen, and the other when it’s tensioned. How do you unload a bow string? You push it off the notches.
I’ve built more than half a dozen bicycle wheels. My set, my spare that my brother road (into the ground - my first set and practically the only problematic ones, but he road over bumps without getting out of the saddle), a set my dad commissioned from me, and a pair that he had me build for a friend. All by age 17.
I then worked as a mechanic for two summers of college. I was never the fastest, but if we had a customer we could not afford to disappoint, I or the senior mechanic got the job because my repairs did not come back.
I saved three or four wheels that would have been scrap by unwinding the spokes halfway and building it back up again like a wheel build. Only added an extra ten or fifteen minutes but it works a charm. When a good customer comes in on Wednesday before an out of town bike ride you can’t afford to fuck it up. I think I only built a couple professionally, and usually singles. That’s a lot of labor and few will pay.
They're ok (i.e., made it through Tour Divide with no issues), done well they're certainly better than badly done steel spokes, but it's not clear if the best builds are better than the best steel builds.
Bike spokes are not loose, they’re under substantial tension. Bolts, I just learned a couple weeks ago, work in the opposite way. A tightened bolt compresses the two pieces of metal together, and when you tug on them, the bolt doesn’t stretch more. The tension instead first cancels out some of the compressive force on the two pieces of metal, before the bolt ever feels more load.
Conversely, all the spokes on the wheel are under tension. When you put the wheel on a surface and push down, the compression cancels out some of the tension on the bottom of the wheel. Cancel out all of the tension, and the wheel turns into a potato chip if you don’t reload it exactly, perfectly on axis. IIRC, none of the prior models or theories for how a spoked wheel works could adequately explain how potato chipping happens. His does.
I used his book to build half a dozen wheels or so and the information it contained to fix many more.
of course in a properly built wheel usually all the spoke are under tension...
i was just demonstrating the fact that the spokes on the upper half of the wheel are supporting the hub and are under greater tension than the bottom ones, the spokes on the bottom half of the wheel should remain in tension, but only through the fact that they are already under tension applied during the building of the wheel.
the fact that the wheel works by tension of the spokes becomes obviously apparent when you start to remove the pretension and then the spokes will feel loose on the bottom half. of course you'd never want to ride a wheel like that because it will quickly become out of true.. just like a walmart wheel.
> of course in a properly built wheel usually all the spoke are under tension...
No, a properly built wheel all of the spokes are always under enough tension you can bounce a penny off them. Always.
Anyway, this sums it up pretty well. Someone has a longer memory than I:
https://news.ycombinator.com/item?id=36891231
If you’re talking about twisted spokes unwinding, you don’t have to reach zero load for that to happen. You just need to reduce the load enough so the rotational force overcomes friction. Tension will also try to unwind a screw as well. But the thread pitch on spokes is very fine, which lessens that force. If you build spokes like wood screws we would have problems and that has nothing to do with reaching 0 newtons.
You can release a lot of those tensions by squeezing the spokes mid build. Just don’t wait until they’re too tight to do it. I had a pulse in my rear wheel that probably came from doing that wrong the first time. Unless it was a factory defect, I must have overtensioned and warped a brand new Mavic aero rim ever so slightly. Expensive lesson, but it could have been worse.
A bike wheel is a linear elastic system, that can be thought of as a superposition of a uniformly set of tensioned spokes as one state, and a set of spokes in compression in the loaded zone (bottom of the wheel) as the other state. So long as the superposition of the two states obeys the limiting conditions (i.e. spokes in tension) they can be analysed separately.
The size of the loaded zone is related to the relative stiffness of the spokes (axial) and the rim (bending), and can be calculated using beam on elastic foundation methods. For typical rim/spoke combinations, this is approximately 4 spokes.
Outside of the loaded zone, spoke tensions essentially don’t change.
I don't know if I found Lego or Lego found me, but I definitely think in terms of shapes. I was past my midlife crisis before I realized that I don't have a large working memory (smaller than average in fact) it's just that I've been doing mind palaces without pictures since I was very small. When I'm thinking of large computer systems I'm essentially thinking of them as physics problems.
I really should figure out space to have a bike again. I never rode when I lived in Seattle (Seattle drivers are nuts) but I don't live there anymore and I need to catch up on 20 years of tech.
You're looking at the macro "It's all in tension" (superposition of two states) and hinkley is looking at the "bottom is a compressive change" (dynamic portion of the load).
What I'm not clear of is if you think that the upper spokes change tension between the unloaded case and the plain gravity load case (force on hub down, ground on rim up at the bottom), or if you expect the top half spokes to increase and the bottom half to decrease in tension. I think this is what hinkley thinks you think.
https://news.ycombinator.com/item?id=36891231
The world is full of papers that are wrong. Including maybe the one this whole thread is about. It’s okay, it happens. Science doesn’t find right or wrong, though a lot of people think so. It finds more wrong and less wrong.
Maybe to put it differently, the "Newtonian" model of flight comes out of assuming CoM applies, which we know isn't universally true.
EDITING: of course it always "applies" in the sense that there is a definable system in which total momentum will be unchanged, the point being that there is no guarantee that's a system in which the plane gets lift greater than its weight
If you're asking how to derive the Navier-Stokes equations, use continuum / conservation principles.
Am I missing something?
Unless you're going to argue that we don't know how an MRI works because we don't fully understand the physics behind superconductivity.
Lee and Kim first discovered the material in 1999 and have spent 20 years doing other things in between getting help to figure out how to isolate LK-99 and reproduce the correct grain structure.
They eventually got a world class physical chemist, Kwon.
There is now a huge bust up within the team, hence the muddled race to publish and claim credit.
Plus even if the proposed-mechanism is incorrect and even if the effect is not strong enough for practical engineering... There's value in a "real" (if weak) superconductor which is both easy to fabricate and easy to run tests on.
It could become a starting-point for dozens of other tweaked formulations, enabling all sorts of not-so-expensive experiments and fresh data about how different parameters lead to different electromagnetic outcomes.
Moreover, you can have more than one thing about a paper be the "relevant" thing.
As another commenter has pointed out, the proposal of a new mechanism seems to be extraordinary and novel, and could lead to an explosion of new research, so it does indeed seem to be "relevant" on its merits.
I also don't see this as a case of the "why" being left unexplained. In the history of superconducting it has indeed been the case that new cocktails have led to superconductivity without the underlying why being understood. But the commenter that you're responding to quotes part of the paper that shows an awfully specific mechanism.
I understand the sense in which there can be a "why" that remains to be explained in certain circumstances, even when you have a mechanism. Who do monarch butterflies have the black and orange pattern on their wings? There's a cause and effect answer but there's also a "why" answer. But with superconductivity, the mechanism is the why, unless I'm misunderstanding here. If other forms of superconductivity rely on other mechanisms, there isn't going to be a general why connecting this case to the other cases, but nor is there anything left unexplained just by explaining the "why" of this case by explaining it's extraordinary mechanism.
That is a very strange explanation. As someone who has done a decent amount of solid-state physics work, I would expect the explanation to involve a mechanism for pairing of electrons. Mere tunneling between quantum wells has been a staple since the "metamaterials" of the 80s and 90s.
That said, the measured curves do not lie, and I haven't kept up with the field. So I'm all ears (and very much hoping the superconducting revolution is upon us!)
How high? Just wondering if it might eventually be possible to use it in some power/clocking distribution layers of a semiconductor chip without bulky cooling.
The critical temperature is 127 C, as the other commenter mentioned. That seems like it's high enough to be useful in a computer CPU.
I suppose there might also be applications for power distribution in a data center. You might use a few large, high-efficiency low voltage DC power supplies to supply the whole site instead of hundreds or thousands of individual power supplies if electrical resistance in cables was less of an issue. (I think this sort of thing is done now, but more at the rack level, since long cable runs cause losses.) You might even use 1V power instead of 5V or 12V.
(Granted, superconducting materials don't have unlimited current capacity, and bad things happen if you exceed the limit.)
There's an additional obstacle factor here which is that the material has to (a) be "sputterable" onto the surface, which may rule out things with fancy crystal requirements, and (b) not adversely react with the rest of the chip, which is why coppper is ruled out (!) and chips use aluminium for metal layers.
[1]: https://en.wikipedia.org/wiki/SPARC_(tokamak)
But yeah, nuclear fusion is cool.
As far as I know, the only explanations for this occurring is room temp superconductivity, or a strong diamagnetism (which would also be very cool to see)!
Is it? What do they care if it takes other labs a week to reproduce?
It's an obvious test to do, so it's quite surprising they didn't do it. Maybe they did and didn't film it, I don't know - but for the trouble of a couple of minutes of time, it's weird not to have it - especially if your method is reproducible.
The dichotomy makes me laugh.
https://scitoys.com/scitoys/scitoys/magnets/pyrolytic_graphi...
https://youtu.be/Wk3seHNmNs8
In this video shortly after this moment you see something very similar looking with pyrolytic carbon: https://youtu.be/VC3r9-OaWes?t=133
I am not an expert in this field though.
https://www.imagesco.com/magnetism/graphite-levitation-kit.h...
https://scitoys.com/scitoys/scitoys/magnets/pyrolytic_graphi...
Whether it makes sense to say the multipole magnet is "multiple magnets" is a philosophical debate in itself.
"Who knows what could come out of that? Robust high-current-density room-temperature superconductors are right out of science fiction (SF readers will recall that one such material was a big plot point in Larry Niven’s Ringworld). Electrical generation and transmission, antennas, power storage, magnet applications (including things like fusion power plants), electric motors and basically everything that runs on electricity would be affected. We could stop throwing away so much generated power on heating up the wires that deliver it, for starters."
They won't replace portable batteries soon, but room temperature superconducting will greatly increase efficiency in all areas of electricity, including higher power motors (the efficiency gains are good enough that superconducting motors and generators have been attempted despite needing supercooling). Also, a simple SMES could easily buffer future BEV truck charging station despite projected 1MW connection per charging truck.
Why do you think any of these are true?
What matters is how lead is handled. With hope, mankind will never lead a generation the way burning millions of gallons of leaded fuel did. Certainly no use of a lead superconductor could hope to accomplish that level of damage.
https://en.wikipedia.org/wiki/Restriction_of_Hazardous_Subst...
It’s notable that the first publications about attempts to reproduce the Cold Fusion experiment all reported positive results.
It’s probably because experimenters who got negative results decided they might have done something wrong so they kept trying, and delayed, and they did not publish until later.
Those early reports of positive results were largely retracted within a few weeks.
[1] https://en.wikipedia.org/wiki/Cold_fusion
Yes, probably
This blog talks about some of the many pitfalls that could mislead researchers: https://coldfusionblog.net/2019/03/13/the-case-against-cold-...
Some of the errors are very subtle. It’s not surprising that mistakes were made
The summary was basically that, designing a reliable calorimetry equipment and experiment suitable for use in Fleischmann-like experiments is just uniquely challenging, it remained an unsolved problem even decades after the initial fiasco. The whole experiment setup is inherently error-prone. I found it was pretty interesting.
One researcher P.J. King who recently attempted a replication [1] commented online [2] that:
> We observed the claimed heat effect, both in magnitude and duration, in our parallel __control__ cells. This indicates a calibration error in the apparatus. One little known fact about these electro-chemical cell experiments is that they are run for a week or more before the effect is observed. Typically, calibration is conducted over a few hours and is done both before an experimental run and intermittently during it, to re-check thermal stability.
> We submit that this approach to calibration is inadequate for establishing a calorimeter’s propensity for heat artifacts. Stability over time periods longer than the experiment should be demonstrated in order to minimize the possibility of misinterpreting the fluctuations that we observed as “excess heat” events.
> Consequently, we contend that all claims of anomalous heat in LENR experiments using electro-chemical cells that do not exhibit thermal stability on a time period longer than the time duration of the experiment itself must be thrown out. As the majority of research over the past 30 years has not demonstrated this kind of calibration stability, that eliminates most of the effort in this field. You can read more about our work on the ReResearch LLC website.
> That is not to say that we know everything about hot fusion in the solid state or how quantum mechanical interactions might impact fusion reactivity. There is much still to be discovered. But these electro-chemical LENR heat experiments are noise, not signal.
[1] Guffey, Mason J., Yang Tang, and P.J. King. 2016. “Attempted Replication of Excess Heat in the Letts Dual-Laser Experiment.” Journal of Condensed Matter Nuclear Science 20 (1): 1–28.
[2] https://www.youtube.com/watch?v=ZbzcYQVrTxQ&lc=UgzFM3zS0QyP5...
* people looking for fusion neutrons, who did not have much experience with the finickiness of neutron detectors and who reported seeing them when they were getting experimental errors, and
* people looking for excess heat, which was simply inherently difficult to measure accurately.
On the other hand, there wasn't a publication delay for the negative reports; within a week the groups started talking to each other and realized they weren't unique in not finding anything.
https://en.wikipedia.org/wiki/Energy_Catalyzer
nothing happened, of course, but the idea of an elegant energy source was so seductive.
If you see a report of a groundbreaking experiment that only measure the heat of the air, you can safely press the "meh" button.
https://en.wikipedia.org/wiki/Oil_drop_experiment?useskin=ve... ("Millikan's experiment as an example of psychological effects in scientific methodology")
Publishing an exact reproduction is difficult, but a new record a few degrees hotter is easy. (And even another variant with a lower temperature and more tolerance for current or magnetic field can be published with the right text.)
Assuming one exists. Assuming it is real.
Abandon the work if nobody can replicate LK-99 within a few weeks and you haven’t really lost out badly.
Also, on the sentences in the manuscripts trying to explain the effect: I think that is wild guess at best. The measurement results done in the manuscripts probably can be taken at at face value (at least until there is a reproduction). Whether they really indicate superconductivity or something else that looks like it in some of the aspects is then a different question.
For almost two weeks they were fully locked, and now one can only see the original post and not the thread, and all browsing is locked out.
> I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, they do not have scientific knowledge of the background theory. In review of these two papers, it’s terrible science, not something malicious (as has been seen before in RT superconductivity work…). Even if these claims turn out to be true, it's still terrible science, and that's my main criticism. Either way, these types of claims are not uncommon, see for example this paper from a few years ago which went nowhere. https://doi.org/10.48550/arXiv.1807.08572
https://www.reddit.com/r/worldnews/comments/159g2k4/comment/...
> So, to clarify for my nonexpert brain, if this were a superconductor and their measurements were accurate:
> Fig 5 means the sample must be completely pure to be a superconductor
> The rest of the paper indicates the sample must have impurities.
> So it's pretty safe to say that either it's not a superconductor or their measurements are wrong (or most likely both). Since they never got it to the critical temperature and showed the full Meissner effect, if the measurements are wrong it's fair to say they don't have evidence for superconductivity anyway, just diamagnetism, which isn't really that big a deal
https://www.reddit.com/r/worldnews/comments/159g2k4/comment/...
In any case, the need for impurities would not itself surprise. Having controlled amounts of impurities is called "doping", it is well-known from studying semiconductors and other high temperature superconductors that the amount of doping can have a huge impact on a substance's properties.
See https://physicsworld.com/a/the-ups-and-downs-of-doping/ for verification of this point.
His earlier comment that graphite can do the same thing is untrue afaict. Graphite can repel the magnetic field but it would slide off, this is why in diamagnetic experiments multiple magnets are used to keep it in place. In the video it doesnt seem to be sliding anywhere, so imo the video is not showing diamagnetism.
https://sciencecast.org/casts/suc384jly50n
Edit: Actually, now I'm not so sure, it does seem like it's held in place by one corner which is always pointing towards the outside of the magnet, so maybe it is just diamagnetism. If anyone has some pyrolytic carbon and wants to try it out?
Edit2: 99% of YouTube videos on diamagnetism have multiple magnets, the only one I could find that has diamagnetism on one pole magnets shows it not working:
https://youtu.be/D-tW8_SRW3g
I think it's more than just pyrolytic carbon
Reminder that flux-pinned levitation only occurs when superconductors are cooled from above to below their critical temperature while in a local magnetic field.
The researchers probably didn’t heat up their big sample above the critical temperature in air as that could have mechanically destroyed it. It was already chipped almost in two.
Casual demonstrations of levitating superconductors involve first submerging the superconducting material in a (non-magnetized) tub of LN2, and then moving it onto a magnetic track. For example, https://www.youtube.com/watch?v=X5EoUD-BIss
Superconducting levitation is just due to the perfect diamagnetism of the superconductor, right?
https://en.wikipedia.org/wiki/Superdiamagnetism
Welcome to Reddit
> However, only one edge of the flat, coin-like material fully levitates, while the other seems to stay in contact with the magnet. Kim says this is due to the sample being imperfect, which means that only some part of it becomes superconductive and exhibits the Meissner effect.
> 1b) shows the resistivity at some unknown temperature. They are applying current and measuring no potential drop. Just what? First, state the temperature, next measure it as a function of temperature. At the critical temperature the resistance drops to zero. All they have shown is that the contact inputting the current is probably disconnected…
this does not pass the sniff test for me. I explained on reddit myself why I think it doesn't make sense.
The only way that could work is if they just straight up fabricated everything, and in that case all bets are off.
I can't comment about the others since I don't know enough about it. Considering 1b) makes no sense with a modicum of knowledge, I really doubt the veracity of the rest.
This isn't 1 experiment. This is 20 years of research leaking because of a fight over credit.
One of the co-authors of the 6-author-paper, Hyun-Tak Kim, is at least answering questions about superconductor theory on Quora starting five years ago, whatever that counts for.
He states there "I am studying the MIT mechanism in strongly correlated systems, the high-Tc mechanism in cuprate superconductors, the MIT devices, and quantum transistors.".
https://www.quora.com/profile/Hyun-Tak-Kim?share=1
In the first paper, they claim to measure zero resistance (on a scale of microvolts), but are very careful not to show full RvT curves - in the second paper, we can still see significant changes below Tc where they include more complete curves. How can the resistance change significantly in the superconducting (zero resistance) state? We can actually see significant noise in paper 1 fig. 1c in the ohmic state and it even appears to behave as an insulator at 0 field (increasing resistance with decreasing temperature), but a metal with applied field. There's something wrong with the measurement.
400 K is an odd choice for your superconducting temperature, and just so happens to be the top end of what an MPMS system can measure so is not completely random. Surely it makes sense to measure significantly above this with one of the oven attachments, verify these results with collaborators at other labs even.
10 Gauss is an extremely small field to use for a ZFC-FC measurement and again if their superconducting Tc is at or above 400K they need higher temperature data to show anything about the phase transition.
The claim that they have measured the density of states is completely unjustified - not even a citation. I don't know how you can believe that to be the case.
And in general the presentation both of the data and the paper itself is poor - if you just made a groundbreaking discovery like this, wouldn't you care?
Hell no! If I had made a discovery of similar magnitude I would have done exactly what they’ve done: push out a rough preprint ASAP to reserve my Nobel prize, then take a deep breath, relax and take my time dotting ‘i’s and crossing ‘t’s for the real paper in Nature.
That doesn’t mean they’re correct, but there’s nothing inherently suspicious about the way this has unfolded.
Their paper is weak on data / results.
This is exactly what you would do if your team genuinely believed you had discovered something monumental.
In poker terms they are "all in" and they want to get called.
That's why it is so interesting. If they had posted lots of extreme results but it needed $10m to replicate then I would be thinking "fraud". It would look like a bluff.
In realistic terms it seems they're grabbing for the prestige without the foundation of crossing their ts. Bad science like this shouldn't be encouraged. It's likely there's not very many groups growing the same material system so they have the time to spare. A paper like this wouldn't be on the arxiv at all if they were 100% sure because they would go straight for the nature publication and take the time to do more follow-up papers while they can.
Edit: to be clear as well, a lot of people are underestimating the time it takes to reproduce a growth even with a manuscript telling you how to do it. People always leave out steps and oversimplify. There is a lot of extra characterization that takes time to double check you have the right material that lines up with what they have here. Only the direct competitors actually already growing this material can do it in a few days.
What? How do they get funding and lab space if they can't read their own measurements? Something is fishy here.
Funding: This research was mainly supported by Quantum Energy Research Centre, Inc. and was also partially supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education(2019R111A1A01059675) and Young-Wan Kwon is supported by a Korea University Grant.
I don't know, either: what's the difference between receiving funding for research and taking investment money for it? Are you talking about public vs private funding?
There's just way too much going on for this to be a sloppy mistake. It's either real or a fraud, and in both cases the alleged errors aren't particularly important.
I'm glad this site doesn't partake in incorrect contrarianism.
This one's in Korean but there are some plots here that I think several people said were missing.
When published, the authors made it clear: this is probably wrong, but we can’t see where we made a mistake … so what if we’re right and just upended relativity theory?
That was turned out to be a measuring error [1]. This one may be the same, though the lead authors publishing two versions of the paper - one with only 3 names, ostensibly because the Nobel Prize can only be awarded to a maximum of 3 people - suggests less modesty and vulnerability on their behalf.
I hope they’re right though!
[1] https://www.nature.com/articles/nature.2012.10099
>Kim has only co-authored one of the arXiv papers, while the other is authored by his colleagues at the Quantum Energy Research Centre in South Korea, some of whom also applied for a patent on LK-99 in August 2022.
>Both papers present similar measurements, however Kim says that the second paper contains “many defects” and was uploaded to arXiv without his permission. In that paper, the work is described as opening a “new era for humankind”.
>Other experts that New Scientist consulted were similarly sceptical about the results and the data produced. Some raised concern that some of the results could be explained by errors in experimental procedure combined with imperfections in the LK-99 sample.
I’m not a physicist expert of superconductors, although I’ve followed quite closely that field since the ‘90s. But if the measurements are similar and correct and if the video of lk-99 levitating above a magnet demonstrating the Meissner effect is not fake, I don’t really have an alternative explanation to account for all of that. I guess that we’ll see what happens in the next week or two. This is too high stakes to take longer than that for a so easily reproducible experiment.
edit: useful comment elsethread by macromaniac on plausibility of diamagnetic effects
Can you please provide a link?
Edit: found it https://sciencecast.org/casts/suc384jly50n
Yeah, I can't be bothered logging in.
If true, it seems wild to sit on this kind of discovery for over two years.
Update: Seems like there might be even more history given the name LK-99 apparently comes from the names of its discoverers Dr. Lee and Dr. Kim, and the year of its discovery, 1999 (https://kr.linkedin.com/in/ji-hoon-kim-03508b80).
"YW Kwon" published the first paper with himself as the 3rd author, and "HT Kim" published the second paper a few hours later with himself as the 3rd author.
Pretty interesting drama if that's the case. May indicate neither paper was ready, but that they all think the result is legitimate.
Would this have implications about possible efficient methods of converting heat back into electricity? Or even just more ways of harnessing heat energy in general. I'm imagining heat pumps built with superconductors could be a critical part of mitigating climate change, but I'm far from a scientist and barely understand the physics here.
You build a big inductor, and because it's superconducting current just goes round and round. At room temperature you have no refrigeration losses, you can build more just as fast as you can kick out superconductor. It would be 100% efficient, have 0 self-discharge, and enormous power capacity and infinite power cycles.
Electricity would be cheaper and more plentiful than water in many areas.
This is an excellent summary and like Derek I have high hopes (but low expectations) that by the end of this week we'll see some tentative confirmation. This stuff isn't particularly hard (or expensive!) to make so that should really make for interesting news and some very fun products if it is proven out.
The bigger the impact the more of a splash it will make in social contexts consequently we see a lot of blatant and cautious naysayers with various explanations and individual explanations for the logic of their refutation.
But it’s If it’s shocking enough, groundbreaking enough, anyone with the expertise to try will do so either to see if it’s right instead of waiting around for someone else to do it and write it up and publish it, or to prove that it’s not and for something this big at least, give BobbyBrocolli a new possible video topic to consider.