13 ms·

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 t

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.

scarmig 3y ago
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.
- bluGill 3y ago
  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.
  - reaperman 3y ago
    > 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.
    - beepbopboopp 3y ago
      [flagged]
      - mlyle 3y ago
        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.
        didgeoridoo 3y ago
        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.
        mlyle 3y ago
        > I’ve never understood how this battle could possibly persist, considering that planes can fly upside-down. 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.
        blagie 3y ago
        > 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.
  - littlestymaar 3y ago
    > 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.
    - scythe 3y ago
      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.
      - thayne 3y ago
        > 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.
        scythe 3y ago
        Lead is absurdly cheap. One dollar a pound! Cheaper than much more common metals like aluminum or magnesium. So I diagnose a low demand. They used to talk about using barium cement but it just can't compete, price-wise.
        et2o 3y ago
        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.
  - phyzome 3y ago
    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.
    - OfferFun6595 3y ago
      It seems a 50/50 situation so long as the lead is able to get the products most companies don't seem to bother a lot about the risks of this exposure
  - pzber 3y ago
    250 milliamps still sounds great for use in antennas.
local_issues 3y ago
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. For sure! https://www.cbc.ca/news/science/science-of-cycling-still-mysterious-1.3699012 https://www.cbc.ca/news/science/science-of-cycling-still-mys... http://www3.eng.cam.ac.uk/~hemh1/gyrobike.htm http://www3.eng.cam.ac.uk/~hemh1/gyrobike.htm https://www.newscientist.com/article/mg22730370-400-how-does-a-bicycle-stay-upright/ 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
- mthomasmw 3y ago
  Do you have a link handy for "we don't know how bikes work" ?
  - prasadjoglekar 3y ago
    [flagged]
    - post-it 3y ago
      I'm not super interested in watching Joe Rogan and RFK, is there a particular bit where they talk about bikes?
      - CSMastermind 3y ago
        There's nothing about bicycles in the video he linked.
        post-it 3y ago
        A classic Freudian clip.
dllthomas 3y ago
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.
- beowulfey 3y ago
  Someone who speaks Korean may have to go through the original paper. It is LK-99 though; I wonder if they tried 99 other combinations first!
  - stu255 3y ago
    No, 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.
    - beowulfey 3y ago
      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.
- gus_massa 3y ago
  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.
ethn 3y ago
They made a synthetic a priori prediction proven by experiment. In science, that's the strongest type of claim.
- seeknotfind 3y ago
  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.
- throwawaymaths 3y ago
  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.
Terr_ 3y ago
> 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.
aaron695 3y ago
[dead]
fnordpiglet 3y ago
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).
- glenstein 3y ago
  Right. The mechanism itself seems extraordinary. And it seems like that mechanism is exactly the "why", the commenter is claiming is more important. Moreover, you can have more than one thing about a paper be the "relevant" thing.
glenstein 3y ago
>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.

scarmig 3y ago

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.

bluGill 3y ago
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.
- reaperman 3y ago
  > 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.
  - beepbopboopp 3y ago
    [flagged]
    - mlyle 3y ago
      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.
      - didgeoridoo 3y ago
        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.
        mlyle 3y ago
        > I’ve never understood how this battle could possibly persist, considering that planes can fly upside-down. 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.
        blagie 3y ago
        > 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.
- littlestymaar 3y ago
  > 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.
  - scythe 3y ago
    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.
    - thayne 3y ago
      > 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.
      - scythe 3y ago
        Lead is absurdly cheap. One dollar a pound! Cheaper than much more common metals like aluminum or magnesium. So I diagnose a low demand. They used to talk about using barium cement but it just can't compete, price-wise.
        et2o 3y ago
        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.
- phyzome 3y ago
  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.
  - OfferFun6595 3y ago
    It seems a 50/50 situation so long as the lead is able to get the products most companies don't seem to bother a lot about the risks of this exposure
- pzber 3y ago
  250 milliamps still sounds great for use in antennas.

local_issues 3y ago

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. For sure! https://www.cbc.ca/news/science/science-of-cycling-still-mysterious-1.3699012 https://www.cbc.ca/news/science/science-of-cycling-still-mys... http://www3.eng.cam.ac.uk/~hemh1/gyrobike.htm http://www3.eng.cam.ac.uk/~hemh1/gyrobike.htm https://www.newscientist.com/article/mg22730370-400-how-does-a-bicycle-stay-upright/ 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

mthomasmw 3y ago
Do you have a link handy for "we don't know how bikes work" ?
- prasadjoglekar 3y ago
  [flagged]
  - post-it 3y ago
    I'm not super interested in watching Joe Rogan and RFK, is there a particular bit where they talk about bikes?
    - CSMastermind 3y ago
      There's nothing about bicycles in the video he linked.
      - post-it 3y ago
        A classic Freudian clip.

dllthomas 3y ago

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.

beowulfey 3y ago
Someone who speaks Korean may have to go through the original paper. It is LK-99 though; I wonder if they tried 99 other combinations first!
- stu255 3y ago
  No, 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.
  - beowulfey 3y ago
    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.
gus_massa 3y ago
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.

ethn 3y ago

They made a synthetic a priori prediction proven by experiment. In science, that's the strongest type of claim.

seeknotfind 3y ago
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.
throwawaymaths 3y ago
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.

Terr_ 3y ago

> 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.

aaron695 3y ago

[dead]

fnordpiglet 3y ago

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).

glenstein 3y ago
Right. The mechanism itself seems extraordinary. And it seems like that mechanism is exactly the "why", the commenter is claiming is more important. Moreover, you can have more than one thing about a paper be the "relevant" thing.

glenstein 3y ago

>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.