Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Successful room temperature ambient-pressure magnetic levitation of LK-99

arxiv.org

Post reply on HN
Print view View original

941–950 of 1001 posts

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#941

Post by anigbrowl »

digbybk wrote: post #841
anigbrowl wrote: post #781

Earlier quoted context omitted.

Conventional conductors have resistance, so when you run electrical current through them they heat up; this is why laptops and desktops have fans to cool the chips, why phones get hot and so on. Superconductors transmit energy without resistance, so the heating problem goes away and the energy costs of running the device go way, way down. Basically you can pump more through smaller wires without worrying about them m…

> The raw materials are fairly cheap, and the production involves heating it to hundreds of degrees centigrade for 24-48 hours Can you also ELI5 why this seemed like such a hard problem to solve up until now? Was it something hiding in plain site?

Same reason a photograph of a delicious meal (the theorized characteristics of the material you want) doesn't give much idea of how to make it, even if you have a stove and live next to a supermarket with all the ingredients.

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#942

Post by anigbrowl »

hackerlight wrote: post #911
anigbrowl wrote: post #781

Earlier quoted context omitted.

Conventional conductors have resistance, so when you run electrical current through them they heat up; this is why laptops and desktops have fans to cool the chips, why phones get hot and so on. Superconductors transmit energy without resistance, so the heating problem goes away and the energy costs of running the device go way, way down. Basically you can pump more through smaller wires without worrying about them m…

> energy costs of running the device go way, way down By how much?

The cost of the cooling subsystem and whatever workarounds you need to do to deal with heat buildup, plus about 10-20% in resistivity iirc. Not a pro engineer, but have some experience with building electronics and embedded systems.

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#943

Post by dredmorbius »

NotYourLawyer wrote: post #160
dang wrote: post #123

Earlier quoted context omitted.

If someone else is wrong and you know more, it would be great to share some of what you know so the rest of us can learn. But please don't post unsubstantive putdowns—they just make everything worse. https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor... https://news.ycombinator.com/newsguidelines.html

Silently leaving incorrect information in place seems worse for the overall state of the thread than a quick note disputing it.

Some indication of where to go for further information is preferable to none.

Consider that HN has ~5 million MAU and that a comment without clarity is confounding many people. Writing and communications generally is a service to the reader not the author.

If you don't have time to look up the precise source, a note along the lines of "I don't have time to find the direct link ..." or "I recall but cannot source ..." would help, along with where generally is the best direction to start looking.

Returning to that comment later to clarify/expand is also useful.

(I do both of these fairly often. And have written ... 612 ... comments with footnotes and references on HN to date: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...>.)

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#944

Post by lesona »

metaltyphoon wrote: post #885
dclowd9901 wrote: post #789

Earlier quoted context omitted.

Completely unrelated, but how does one un-become a particle physicist?

git reset —-hard

git archive --format=tar HEAD

I like the idea that some of us will live long enough to not be defined by our jobs.

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#945

Post by ngc6677 »

mk_stjames wrote: post #735

This is obviously a quickly produced paper to get the finding out but.... I find there to be so much missing and so many things poorly worded or posed about their process that would have taken zero time to expound upon, it's infuriating. "All the reactions are carried out under 10^-2 Pa" OK, I know they mean 10^-2 of vacuum. But why not say that? "10^-2 Pa" isn't enough. Was this a full vacuum oven? Done in sealed qu…

Your point is fair. It feels it also underlies the importance of "continuous teaching and learning", global (or assigned) peer reviewing. At moments in time where discoveries like this one happen, one could hope that beyond "open publishing" like Arxiv, comes a true "science in the open", with room for cooperation. Looking forward evolving further our current system.

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#946

Post by amrocha »

yetihehe wrote: post #496
amrocha wrote: post #163

Earlier quoted context omitted.

Long, hard labor should be rewarded. And it is. They're receiving a salary, and now fame. That's more than enough.

> Long, hard labor should be rewarded. And it is. Why do people ask for raises though? It is somewhat rewarded, but some people don't work long and hard and still have more money. Those working long and hard, having a big useable result want to be rewarded a little more.

Aren't these results mostly luck driven though? Lee and Kim were lucky to go to that university in Korea, lucky that their professor researched superconductor theory, and lucky that the professor's theory was correct.

At the same time, other researchers around the world weren't so lucky.

But because we don't know what's going to pan out without trying it out, the other researchers are just as integral to the process of discovery.

Is it fair to reward Lee and Kim for their luck, and let everyone else get screwed? Wouldn't it be more fair to make sure everyone is appropriately compensated to begin with?

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#947

Post by eastbound »

marginalia_nu wrote: post #671
constantcrying wrote: post #598

Earlier quoted context omitted.

I think there are multiple big reasons they didn't publish sooner. It is pretty clear that they were convinced, but had insufficient evidence to convince others. Additionally there had recently been a sensational fraud in their field so journals would have been extremely sceptical. It seems to me they were just in the process of constructing a convincing paper, which included convincing tests and could have been acom…

It's also worth mentioning that room temperature superconductor "discoveries" happen a lot, and have always turned out to be a disappointment. It's been considered to be within the same bermuda triangle of scientific vaporware that demarked by quantum computers performing useful tasks, fusion power generation, that sort of thing. Always just around the corner and dude trust me it totally works in my lab. It's basical…

Talking about fusion, isn’t the major part of the Tokamak plant in Cadarache in France, dedicated to cooling down the superconductors to zero temperatures?

If we make a leap in room-temperature superconductors, do we also make a leap in fusion?

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#948

Post by [deleted] »

mort96 wrote: post #407
someplaceguy wrote: post #386

Earlier quoted context omitted.

> superconductivity is (by convention) less than 10^-11, Ah, so you're saying that superconductivity is not actual zero resistance, but something close to it, and in fact only a factor of 1000x less resistive than the best conductor? If that is so, this is something that I had previously thought would make a lot more sense to me. But in that case it's not intuitive to me how SMES is possible with a 0% discharge rate.…

No, I believe it's literally zero but we don't have a measurement apparatus with infinite precision so we need some cut-off.

[deleted]

Re: Successful room temperature ambient-pressure magnetic levitation of LK-99

#950

Post by kzrdude »

dotancohen wrote: post #907
Sharlin wrote: post #876

Earlier quoted context omitted.

Magnetic force scales as 1/r^3, not 1/r^2 like gravity. That's why your standard issue fridge magnet measurably attracts stuff only from a very close distance, but when it does, it easily counters the gravitational attraction of the entire planet¹. This 1/r^3 relationship can be derived easily enough by integrating, but essentially it's because magnets are dipoles and the farther away you are, the smaller the apparen…

> Magnetic force scales as 1/r^3, not 1/r^2 like gravity The magnetic force and gravity are two of the four fundamental forces, no? The others being the strong and weak nuclear force? At what rate do those two scale at?

Yes, in that model, it's not called the magnetic force but the electromagnetic force (combining both types of interactions into one mechanism.)

This one has a table that summarizes the answer to your question

https://en.wikipedia.org/wiki/Fundamental_interaction

Post reply on HN