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Can someone ELI5 to those of us who aren't even sure what a superconductor is?


When you cool some materials down until they are very cold, something weird happens: Their electrical resistance vanishes, and they start rejecting all magnetic fields. It's important to note that this is not a continuous process where things slowly change until it reaches zero, it is a step change after which everything related to electricity works very differently.

This doesn't mean there is no resistance in the wires that move electricity to your house, because superconductors only work when cooled to unpractically low temperatures, meaning they can only be used for special things like the magnets in MRI machines and fusion reactors.

That is, until now. This paper reports on a material that remains a superconductor at 127C.


> Their electrical resistance vanishes

To put this in further context, RTP superconductors mean compact, low-power MRIs and a massive shrinking, simplification and superpowering of magnetic-confinement fusion and ion propulsion designs. It blows apart chip designers' thermal constraints and opens up entire classes of energy-storage chemistries.

If this is real, it will be the defining discovery of our lifetimes.


> superpowering of magnetic-confinement fusion

though worth remembering we still don't know how to stabilise plasma or sensibly generate electricity from it.

> It blows apart chip designers' thermal constraints

really? much of the heat in chips comes from the /connections/ between transistors etc?


A material with no electrical resistance. Build a wire out of it and the voltage will be the same on both ends.


That also means that electrons flow unimpeded from one side to the other.

Great for energy transmission (though you can't put too much current, superconductivity breaks down under strong fields).

Great for fast circuits, such as CPUs, that don't waste energy just transmitting data.

Great for storing energy (in principle) by just making a loop and let current flow indefinitely.

Related, great for building powerful magnets (that are just such a loop) without wasting too much energy. Applications: MRI machines (they already use superconductors but are bulky due to the need for cooling) and other powerful magnets: LHC/particle accelerators, Tokamaks/plasma control/fusion. But also improved motors and generators.

Nice for levitating stuff since they levitate above magnets "for free" (due to their interaction with electrical fields, they reject magnetic fields). Possible applications for maglev (trains, etc), magnetic bearings, etc.

And possibly a lot of new applications opened up if you remove the need for cooling (Faraday cages?).

Of course, it all depends on how much current and temperature it can handle. But if this is real, just having one material is game-changing, and it will surely be improved upon by looking for similar properties in other materials. This one contains lead, which is a non-starter for a lot of applications due to its toxicity.

Someone else wrote a few use-cases in that other comment: https://news.ycombinator.com/item?id=36866686


> This one contains lead, which is a non-starter for a lot of applications due to its toxicity.

We've been using cadmium-based batteries for ages despite Cadmium being even more toxic than lead, and are still using lead batteries in ICE cars AFAIK. Lead toxicity isn't really a problem unless you burn it, deliver water through it or you put it on paint that end up in kids' mouth…


I agree that it can still be used in a lot of applications, but this would probably restrict its use in everyday items, such as over-the-counter magnetic bearings,long-distance transmission lines, or consumer electronics (RoHS).

Lead batteries for cars are a bit special, as the whole supply chain goes both ways for recycling, while batteries are rather self-contained and not usually exposed to harsh environments.

Though I suspect you are right in the end, as it's a matter of judging the risk vs reward, I wouldn't be surprised if other materials with a similar structure end up performing similarly.

Pb is also quite hard to use in integrated circuits, as far as I know. I am no material scientist, but it could be due to its low melting point or tendency to contaminate other metals.


And the voltage will be the same on both ends when it has current flowing through it.


The only thing that holds a voltage without current flowing through it is an insulator.


This isn't even wrong. A voltage can be present without a current flowing. Touch any live wire to get an instant demonstration that there indeed was a voltage present even if no current was flowing. Not because the wire is an insulator but because it wasn't at that point in time conducting any current. Your finger (also not an insulator) closing the circuit however and then allowed current to flow.


Ouch, you need to take another look at that.

The definition of an insulator is a material that holds (up to some amount of) voltage without electrical currents appearing.

Your example needs two wires. And the wires themselves don't have any voltage. All of the voltage is between them, and is only there because they are insulated from each other.


No, the definition of an insulator is a material that doesn't have the ability to carry current because it has no free electrons.

You are conflating 'insulated' and 'insulator'.




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