# Room temperature superconductors **URL:** \ **Category:** Factual Questions\ **Created:** [September 29, 2013, 7:13pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943 "2013-09-29T19:13:55Z")\ **Posts on this page:** 13\ **Page:** 2
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [September 30, 2013, 2:01pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/21 "2013-09-30T14:01:49Z")
> [@Chronos](#): > > All metals are superconducting at sufficiently-cold temperatures (in the neighborhood of single-digits Kelvin), … Nitpick: only thirty elements have been observed to superconduct at ambient pressure, and about twenty more have been observed to superconduct at higher pressure. That still leaves over thirty elemental metals that haven’t been observed to superconduct. [Here’s the data as of 2009.](http://physics.wustl.edu/~jss/NewPeriodicTable.pdf) In particular, some of the metals that are the best conductors of electricity at room temperature (copper, silver, and gold) have never been observed to superconduct. Now, this doesn’t mean that they can’t superconduct, just that it might require ridiculously pure samples and/or ridiculously low temperatures and/or ridiculously high pressures to make it happen. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [September 30, 2013, 3:03pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/22 "2013-09-30T15:03:51Z")
I recall reading about a suggestion to create a power storage unit (like a battery) with a cooled superconducting loop. One suggestion was that a quarter-mile loop could hold enough power to run a city the size of San Francisio for a few hours thus reducing the need for peak load generators. the downside - the magnetic fields still tried to expand the loop, so it had to be embedded in bedrock. Maybe such a device could be created as a small home appliance for the DIY type for running off the grid, with the added bonus that if the refrigeration system failed, a couple of hundred kilowatt-hours of stored energy becomes heat in an instant. ---
**Author:** ![get\_lives](https://avatars.discourse-cdn.com/v4/letter/g/ecb155/32.png) [@get\_lives](https://boards.straightdope.com/u/get_lives)\ **Post date:** [September 30, 2013, 3:11pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/23 "2013-09-30T15:11:45Z")
> [@sylmar](#): > > I know, I know, not just anybody can lead the Boston Philharmonic. But with a thin baton of [graphene](http://arstechnica.com/science/2012/01/graphene-may-exhibit-exotic-superconductivity/), maybe an everyday smuck can do it without having to be immensely chill… 😉 Not to get off-topic, but it really depends on the piece of music (and the orchestra) as to whether “anyone” can conduct it. With an orchestra at the level of Boston, literally anyone who can avoid physically assaulting the musicians can conduct some pieces, like simple marches and other pieces that don’t have tempo changes. The orchestra will just ignore the incompetent arm-waving and play on. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 30, 2013, 3:59pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/24 "2013-09-30T15:59:40Z")
> [@](#): > > Maybe such a device could be created as a small home appliance for the DIY type for running off the grid, with the added bonus that if the refrigeration system failed, a couple of hundred kilowatt-hours of stored energy becomes heat in an instant. For some definitions of “bonus”, at least. Like, the kind of definition that includes large explosions. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 30, 2013, 4:15pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/25 "2013-09-30T16:15:34Z")
> [@Habeed](#): > > I looked this up. There are certain orbits near the earth that are permanently in shadow. Which orbits? The only candidate I could think of was L2, but even that, the Earth is too far to fully shield the Sun. > [@filmore](#): > > Here’s a cool video of a superconducting disk floating around a mobius strip of magnets with explanations of how it all works. > > [http://www.youtube.com/watch?v=zPqEEZa2Gis](http://www.youtube.com/watch?v=zPqEEZa2Gis) That is nice, but I wish he had said which way the magnets were aligned. North always out from the track? North circling each section of the track? ---
**Author:** ![aNewLeaf](https://avatars.discourse-cdn.com/v4/letter/a/ac91a4/32.png) [@aNewLeaf](https://boards.straightdope.com/u/aNewLeaf)\ **Post date:** [September 30, 2013, 4:22pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/26 "2013-09-30T16:22:44Z")
> [@ZenBeam](#): > > Which orbits? The only candidate I could think of was L2, but even that, the Earth is too far to fully shield the Sun. A little gold foil sunshade can be pretty effective. 😉 ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [September 30, 2013, 6:26pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/27 "2013-09-30T18:26:25Z")
> [@aNewLeaf](#): > > As long as the device isn’t laying out on the surface during bright semilunar, it will stay cold. “cold” is an vague term. How deep do you have to bury something, or how large a shade to you need to keep objects on or near the lunar surface from reaching, say 134 K when facing the sun? > [@](#): > > There’s no issue with radiating waste heat from a superconducting device, as there’s no waste heat to radiate. That assumes that every bit of wiring and electronics is superconducting all the time. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [September 30, 2013, 7:25pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/28 "2013-09-30T19:25:07Z")
> [@Chronos](#): > > For some definitions of “bonus”, at least. Like, the kind of definition that includes large explosions. Special warning to fire department - in the event of an issue with this house, spend your efforts evacuating the neighbourhood instead… ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 30, 2013, 9:01pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/29 "2013-09-30T21:01:51Z")
> [@naita](#): > > “cold” is an vague term. How deep do you have to bury something, or how large a shade to you need to keep objects on or near the lunar surface from reaching, say 134 K when facing the sun? [_Near-Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits_ (PDF)](http://www.gps.caltech.edu/classes/ge151/references/vasavada_et_al_1999.pdf) has some nice results for both the Moon and Mercury. Based on their modeling, by 1 meter deep\*, the soil temperature is constant. See Figure 4, the top two images, which are at the equator, and at 85 degrees North. The temperatures are 250 K and just about 134 K respectively. Further down, they consider craters near the poles, and even on Mercury, there’s a crater where the maximum temperature is below 100 K. See the big glossy color picture. Below that they consider Mercurial and lunar craters at several different latitudes, in Figure 9. - Which seems too shallow to me, but maybe without water, Lunar soil is more insulating than Earth. Also, they say the seasonal variation is small near the equator. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [October 1, 2013, 9:00am UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/30 "2013-10-01T09:00:41Z")
> [@ZenBeam](#): > > [_Near-Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits_ (PDF)](http://www.gps.caltech.edu/classes/ge151/references/vasavada_et_al_1999.pdf) has some nice results for both the Moon and Mercury. Based on their modeling, by 1 meter deep\*, the soil temperature is constant. See Figure 4, the top two images, which are at the equator, and at 85 degrees North. The temperatures are 250 K and just about 134 K respectively. So apart from the polar regions it appears there’s nowhere on the moon that’s cold enough for superconduction without active cooling. (Even if it’s just insulation and putting a shade up in daytime.) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 1, 2013, 3:25pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/31 "2013-10-01T15:25:43Z")
Actually, the 85 north location would just barely make it. You’d still probably want some active cooling to account for waste heat and small temperature fluctuations (the results of going over critical temperature are catastrophic enough that you want a nice comfortable margin), but you wouldn’t need very much active cooling. ---
**Author:** ![GargoyleWB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gargoylewb/32/199_2.png) [@GargoyleWB](https://boards.straightdope.com/u/GargoyleWB)\ **Post date:** [October 1, 2013, 7:21pm UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/32 "2013-10-01T19:21:48Z")
> [@bump](#): > > FWIW, liquid nitrogen boils around 77k, so 134k superconductors are an entirely different ball game in terms of usefulness than the older liquid helium ones. …and within the temperature band of Mars. Imagine space and Mars colonies not having to worry about annoying little things like resistance and transmission loss. “Houston…The Smeagol has landed…we’ve gone superconductive…” ---
**Author:** ![appleciders](https://avatars.discourse-cdn.com/v4/letter/a/85f322/32.png) [@appleciders](https://boards.straightdope.com/u/appleciders)\ **Post date:** [October 2, 2013, 12:06am UTC](https://boards.straightdope.com/t/room-temperature-superconductors/669943/33 "2013-10-02T00:06:10Z")
> [@Habeed](#): > > I looked this up. There are certain orbits near the earth that are permanently in shadow. The ‘background temperature’ of space is 3k. This means that only passive refrigeration would be needed to keep superconducting equipment on a spacecraft cold (by passive I mean heat fins, coolant and pumps, things that don’t involve a heat engine) > > Of course, the $10,000/Kg that it costs to place things in LEO makes paying for liquid nitrogen or liquid helium look cheap. What orbits? I’d love to read about that. Where did you look that up? > [@aNewLeaf](#): > > Space is not cold, agreed. Objects in space are cold, however. The Moon is cold. > As long as the device isn’t laying out on the surface during bright semilunar, it will stay cold. > There’s no issue with radiating waste heat from a superconducting device, as there’s no waste heat to radiate. > > (Agreed that orbital devices are somewhat problematic. But if a communications satellite can manage the heat, a computing one could as well, I assert.) > But back Earthside, I think even liquid nitrogen is too cold for practical use. You could replace liquid helium cooling in devices such as MRI machines, but I think it’s still too cold to open up new markets and new devices. No chance of home use, for example. > [@aNewLeaf](#): > > A little gold foil sunshade can be pretty effective. 😉 Uh, using a sunshade that’s attached to a satellite will cause that sunshade to conduct heat into the superconducting part of the satellite. And modern satellites manage in direct sunlight specifically because they’re not superconducting and can therefore function at higher temperatures. Even on the surface of the Moon with no air to conduct higher temperatures toward the superconductor, you’d still see that sunshade heat up and radiate heat down toward the superconductor. Underground on the Moon or in polar craters where the sun never rises might be viable. Some of the temperatures thrown around in this thread are just barely higher than the maximum temperatures that modern superconductors can operate at. [Previous page](https://boards.straightdope.com/t/room-temperature-superconductors/669943.md?page=1)