[hwillis]

You can't get CT scans very often, because they hit you with large doses of ionizing radiation. Ultrasounds are low-resolution spotlights; you shine them at a particular spot to diagnose something specific.

With this you could get an MRI at your annual checkup. You could diagnose all number of diseases like that, not to mention 95% of cancers. Each year your scan is automatically compared to the previous year, and any sudden changes in morphology can be biopsied. The learning would be revolutionary for medical science as well- right now we have so little data on what kinds of benign growths people have that our best method for figuring out if a mass is a problem is asking if there are any other symptoms. Not to mention entirely new kinds of medical devices would be possible, eg using SQUIDs.

Ground-imaging MRI would also be revolutionized. Archeology, paleontology, geology, mapping resources and finding minerals would experience a quantum leap. You would be able to drive a car through the desert and spot fossils or faults or mineral signatures.

Space travel would become essentially free with the use of launch loops. Which would also make long-distance travel incredibly cheap and practically pollution-free. You would need electricity alone to reach low earth orbit, or to accelerate planes to multiples of the speed of sound.

Grid-level storage, peaker plants and load-following would become nearly obsolete. Superconducting catenaries would connect every nation on earth. Normally plants have to turn off when everyone goes to sleep; now factories in China can be powered by US fission. Canadian homes could be kept warm by Australian solar. HVDC interlinks would be obsolete. We might eventually transition away from AC power entirely.

CPUs could be anywhere from 10% to 50% more efficient. GPUs even more so. Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.

[XorNot]

> We might eventually transition away from AC power entirely.

This is actually a really good point I hadn't fully considered, but it's right: the primary reason we use high voltage anywhere is because it minimizes resistive losses (and the reason we use AC is because it's easy to transform between voltages).

But most of the stuff in my home doesn't need high voltage - it's all running at 5V or 12V. Or it's a motor which is magnetically driven and depends solely on magnetic field strength (which is independent of voltage).

If all your conductors have zero resistance, then high voltage is obsolete. You could safely run a residential property on 12V power. Home electrical hazards would a thing of the past.

[myrmidon]

This is drawing completely wrong conclusions from erroneous oversimplifications:

We're using high transmission voltages to keep current down. Superconductors would not change this AT ALL; superconductivity generally breaks down not only with temperature increases but also magnetic field strength (i.e. current).

Switching large currents is also a hassle; especially with non-resistive loads.

And completely changing household electricity architecture is simply not gonna happen just to marginally improve safety, cost/benefit ratio is WAY too high.

[XorNot]

A superconductor running at high amperage requiring more superconductor is still a superconductor. The losses you take are zero.

Any amount of cross-section of copper though is not - you take losses at (I^2)*R. You lose power as a square of the current.

There is an enormous difference between using superconductors at high currents and using any normal material.

Obviously the impact of this depends on what the critical current of a hypothetical room-temperature superconductor ends up being...but REBCO tapes achieve current densities of >40,000A/mm2 (at 77K). Depending on what you end up with, the expense and danger of maintaining the high voltage infrastructure could easily be seen as not worth it - particularly if it speeds up the ability to build out and maintain power lines.

[myrmidon]

> The losses you take are zero.

Sure, but transission losses are generally a low single digit percentage-- eliminating those will not have much impact, but on the other hand your superconductor is EXTREMELY unlikely to be even close to cost competitive with aluminum/steel core wire.

Even if you could achieve critical currents comparable to conventional high-temperature superconductors at ambient temperature (which appears *highly* doubtful!), keeping high power transmissions lines at human-survivable voltages would be a tremendous waste of super-conducting material.

And even inside homes it seems quite farfetched to me to scale down voltages-- nobody wants to use plugs and switches rated for 200 amps just for their cheap toaster...

[jacquesm]

A typical HVDC line is a work of art, I wouldn't compare it with a chunk of aluminum or steel wire.

[myrmidon]

I was not comparing to HVDC; aluminum with steel core is what's typically used in generic overhead power lines.

[sz4kerto]

> Sure, but transission losses are generally a low single digit percentage

Around 6-8% per 1000 km. That's a lot.

[Doddler]

I can't imagine any scenario where using 1000 km of superconducting material would ever be worth it to save 6-8% though.

[jacquesm]

It's interesting to see how many assumptions about our world are underpinned by the lack of superconducting material. That also immediately gives you an idea of how transformative (heh.) room temperature superconductors would be.

[hwillis]

> But most of the stuff in my home doesn't need high voltage - it's all running at 5V or 12V.

85 volt DC carries the same power as 120 volt AC, but 85 volts DC is essentially safe to touch. The human body has a much lower AC impedance, so it's MUCH more dangerous. DC does still hurt, though.

40-80 volts (see also: split phases) DC is very convenient for most electronics. It's really just things with batteries that want 5-12 volts, but stepping that down isn't too hard.

At the grid scale, it's a question of which is cheaper. If the infrastructure becomes much more expensive (because the wires are SC) then you can save money by using DC (which gives you 41% more power). If its cheaper to use transformers than it is to use more superconductors and semiconductors to convert voltages, they'll do that.

Either way the grid would stay relatively high voltage (10s of kV), because it's just always going to be worth it at that scale to minimize the conductor area.

[Workaccount2]

We use AC because changing voltage levels with it is extremely simple and efficient compared to DC.

In fact the only (practical) way to convert DC voltage levels is to convert to AC, do the level conversion, then convert back to DC.

Believe it or not, DC already is more efficient for energy transfer and why there are already DC high voltage transmission lines. You don't have to deal with reactive parasitics.

But again the killer is that AC voltages are so easy to switch and can by done with >99% efficiency.

[fellowmartian]

Full body MRI scans are only expensive in the West, outside the west you can get one done for $250. This is a labor and regulatory capture problem and not a technology problem and will not be affected in any meaningful way by better superconductors.

[hwillis]

Even if it were $250, that's a pretty high cost relative to the annual cost of insurance. It's too high to justify as a routine diagnostic tool. The financial benefit here is that earlier identification would save money in the long term treatment. MRIs don't cure cancer, so the direct benefit only applies to the limited savings on a very small subset of people of the people who actually get cancers that could be identified earlier.

The real benefits are indirect (from the viewpoint of the insurance people who unfortunately pay for it)- quality of life is much better if you catch it earlier, and the medical research benefits are huge.

Realistically, it's also not $250 even outside the US- not for the resolution needed to diagnose cancers. That's below the depreciation cost of a high end (say $1M) machine. 12 scans a day (it takes roughly an hour for an average scan, 12 is per day per machine is pretty average[1]) 7 days a week for 10 years is 43,800 scans. So ignoring interest, labor, and absolutely everything else that's $228 per scan.

A full body MRI takes an hour only for small patients. More realistically 1.5-2 hours.

[1]: https://www.auntminnie.com/index.aspx?sec=ser&sub=def&pag=di...

[ricardobeat]

$250 is a ton of money outside ”the west” (I assume you mean US/Europe/Aus). It’s roughly the minimum wage in Brazil.

[fellowmartian]

I know, but my point is that the price doesn’t scale with machine and helium costs, but with labor costs and the level of insurance racket a particular country has. Obviously it’d be great if we didn’t require helium supply chains to make medical scans, but unfortunately we can’t fix everything with technology alone.

[jacquesm]

The cost of the machines will drop considerably so it definitely will have an effect. That $250 is still a lot of money for many people and if not covered by insurance and in the developing part of the world it is utterly unaffordable.

[aqme28]

> Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.

I don't know enough about how this material behaves, but a superconductor "quench"* can be pretty catastrophic. I could see a room temperature superconductor battery causing fires from a quench.

*: https://en.wikipedia.org/wiki/Superconducting_magnet#Magnet_...

[andbberger]

we could do annual scans with current tech. the fundamental limitation of MRI is proton relaxation time, which limits the sampling rate. the path to reducing scan time and thus cost is to use a more sophisticated reconstruction method to reduce the number of required samples. this is being worked on.

i don't have any data here, but I am dubious that a room temperature superconductor will bring down the price of MRI machines. a room temp superconductor only saves you a dewar, about $50k of liquid helium and a cryocooler. you still have to build the rest of the MRI, which is an _extraordinarily_ sensitive instrument

> Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.

depends how sharp the phase transition is.

[gibolt]

There is a lot of infrastructure around the MRI in order to support liquid helium storage, cycling, and inter-device pathways. It isn't just what you see in the room.

It might still be a large machine, but a bunch of bottlenecks disappear. With that, it is only a matter of time until a startup develops a much cheaper, smaller, and more efficient device.

[ttyprintk]

Philips is a big player making the assumption that the next generation of MRI will be smaller, cheaper, and more widely available. But, I can confirm smaller players are operating on that assumption as well.

[MauranKilom]

CMIIW but the main thing to make acquisition times more reasonable is higher magnetic field strength. Which, leaving all the technical questions of achieving it aside, comes with other fun constraints like requiring heavy shielding for the room and of course very careful control of what kinds of metallic objects can go near it...

[im3w1l]

It's my understanding that long-known high temperature superconductors already don't require helium cooling. How does that fact fit into the picture?