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8 votes
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Are there politics in mathematics?
Curious if there are movements within the governance or research pertaining to the field that act to promote or suppress certain ideas? Was watching the “Infinity explained in 5 different levels”...
Curious if there are movements within the governance or research pertaining to the field that act to promote or suppress certain ideas? Was watching the “Infinity explained in 5 different levels” and thought… maybe there are trends for or against interpretations and/or abstractions that get a rise in people…
33 votes -
Superconductor megathread
Hey everyone, As a few of you may know, there was a paper released a few days ago claiming that an Room-Temperature Ambient-Pressure Superconductor (RTAPS) was created. You can see the original...
Hey everyone,
As a few of you may know, there was a paper released a few days ago claiming that an Room-Temperature Ambient-Pressure Superconductor (RTAPS) was created. You can see the original paper here: https://arxiv.org/abs/2307.12008
To bring things into perspective if this holds true we would likely dispense with energy and transportation concerns. It would be akin to the discovery of fire, penicillin or the transistor. A groundbreaking change. See here for a more detailed, bullish list of things it can help with: https://nitter.net/Andercot/status/1685088625187495936
There are many communities that are discussing this. The best summary I was able to find is here: https://forums.spacebattles.com/threads/claims-of-room-temperature-and-ambient-pressure-superconductor.1106083/page-17
There is still a very much active debate there (and elsewhere online) of people on the viability of the original people. Many are pessimistic that the evidence is scant and that the original publication does not hold its water. An interesting summary of the sentiment of a part of the community can be found through the (faux) betting market of Manifold here: https://manifold.markets/QuantumObserver/will-the-lk99-room-temp-ambient-pre
On the link above they are also diligently tracking any replication attempts. Currently we are at the stage were theoretical simulations have validated the possibility of the purported materials to be superconductors (https://arxiv.org/abs/2307.16892).
Finally, a nice replication attempt that tried to make the creation process better and demonstrated some of the effects required to prove superconductivity (scroll up): https://twitter.com/iris_IGB/status/1685804254718459904
This is very exciting, because even if some properties are valid, it gives a mjor boost to the whole field.
143 votes -
Nuclear fusion discussion
I'm a big fan of nuclear fusion as a concept and hope to shift toward doing active research in the field at some point. I'd like to open this discussion to talk about topics regarding nuclear...
I'm a big fan of nuclear fusion as a concept and hope to shift toward doing active research in the field at some point.
I'd like to open this discussion to talk about topics regarding nuclear fusion as a future energy source. To start, I'll lost a couple of ongoing fusion efforts I'm familiar with.
ITER:Of course the biggest fusion project is ITER, the massive multinational collaboration which is building a massive tokamak reactor in France. Unfortunately ITER will never produce power for average people, as it's purely a test reactor with no plans to be connected to the grid. The following effort to build a functional grid connected reactor, DEMO, isn't set to be built until at least 2050. This has resulted in a considerable number of private ventures trying iut experimental alternative approaches.
HELION:At the time of writing this, there's quite a bit of buzz surrounding Helion energy, both because of the ambitious timeline theyve recently proposed as well as the investment of Sam Altman of OpenAI fame. Helion uses an FRC topology, which I personally think is a really cool idea. Basically it's a tokamak without the physical shell around it, and is kept sustained by the internal plasma physics. Helion also has another interesting quirk, they are not pursuing the typical DT fuel strategy, but are instead planning to use DD fusion to breed He3 and use DHe3 fusion as the primary energy source. I think this is a good idea because DHe3 fusion is "aneutronic", whereas DT fusion produces high energy neutrons that are somewhat of an unsolved problem to deal with. I wonder though, how they intend to deal with the inevitable tritium pollution that DD fusion creates, and how they will separate that out before Iit creates neutrons anyway.
TRIALPHA:In addition, another major company TriAlpha Energy, also pursued FRCs, hoping to use an alternative proton-boron11 mix to achieve aneutronic operation. I think they've sort of pivoted toward being more a neutron source than working toward breakeven.
HB11: A recent proposed approach is HB11, which is also going for proton-boron fusion. Now with Tri Alpha this seemed really dubious, because hydrogen boron has a much lower cross section for fusion than other options, even the DHe3 that Helion is doing. In addition, boron has way more electrons than hydrogen, so a proton boron plasma has more electrons with causes more bremsstrahlung loss. HB11, however, thinks they can overcome this through high energy laser acceleration. They want to use a high power laser to shoot a fuel pellet into a target. This supposedly will work much better than heating the stuff, because the laser will impart a specific impulse and thus the thermal spectrum of the impact will have a much higher Q factor centered around the cross sectional peak. I'm not really convinced on this, just because I feel like that thermal spectrum would only last for the first few atomic layers of impact before it doesn't really matter amymore.
CFS: The next option I would consider to be one if the most popular fusion startups is Commonwealth Fusion Systems. They have what I'd consider the most conservative approach, they are attempting to build a Tokamak design like ITER, but hope to reduce the size considerably by taking advantage of advances in superconductor technology with REBCO tapes.
W7X:The next reactor type I'll mention was in the news a lot a few years back, the Wendelstein-7X in Germany. This is a stellarator design, the crazy twisted car wreck of a thing you may have seen before. The stellarator is shaped that way so that it doesn't require an induced current like the tokamak to have magnetic helicity, because the shape does that automatically.
ZAP:Another well liked dark horse is Zap Energy. They're not as flashy as the other reactors but seem to be working off solid physics that have been proven out over many years. They're trying to do sheared flow z-pinches, which is basically creating a lightning bolt that's perfectly straightened out and super dense.
DPF:One more somewhat obscure option is Eric Lerner's Dense Plasma Focus approach. I'm a little puzzled by this option because it seems to be the exact opposite of Zap, where they make an incredibly twisty lightning bolt instead of a straight one.
FUSOR/POLYWELL:There are a couple reactor types that get mentioned often but are more or less obsolete are the Fusor and the Polywell. A Fusor is a neat device that can be built to fit on a desktop and still produce actual fusion reactions, but has a fundamental design flaw of a physical electrode inside the plasma that introduces too much conductive heat loss. The Polywell is a more advanced concept thay tries to create a "virtual" cathode with orthogonal magnetic mirrors, but I think after many years of experimentation researchers were unable to validate the formation of such a virtual cathode.
NIF:One option that is sort of tangential is the NIF, which you might have heard technically produced more energy than it produced. I dont think its necessarily going to go anywhere, mostly because it's more a weapons program than an energy program, but I think the chirped pulse amplification technology they use is really cool.
GENERAL-FUSION:And finally I'd be remiss if I didn't mention the very highly funded and publicized General Fusion. I definitely give them points for pure childlike wonder. The original pitch was they were going to take a giant swirling tornado of molten metal, fire a ball of plasma into the eye of the storm, then smash the whole thing from all sides with a hundred giant hammers. To be honest is such a wild concept that I don't really know if it really makes any sense or if it's a fever dream. It's undergone a few revisions after finding out that certain parts of its concept just weren't going to work. This doesn't inspire a ton of confidence, but also shows flexibility in their thinking.
There's definitely lots of other companies with other variations, but this gives a general idea of the huge range of ideas and approaches being pursued. I think it's a really cool field to explore and I'd love to hear all your thoughts about it.
48 votes -
Is anyone here interested in talking about volcanoes?
So, I have a casual interest, but I find them intriguing. I recently took a trip to Lassen National Park, and saw this boiling mud pool. https://imgur.com/n6dV92U. I am planning a trip next year...
So, I have a casual interest, but I find them intriguing. I recently took a trip to Lassen National Park, and saw this boiling mud pool. https://imgur.com/n6dV92U. I am planning a trip next year to Pompeii and Herculaneum. Someday, I am interested in seeing volcanoes in Hawaii and Iceland and maybe more. I casually enjoyed HarryTurtledove's survival novels about Yellowstone erupting, although they are not great literature by any means.
What about you? Any cool experiences with volcanoes or bucket list plans that you would like to share? Do you know fun facts? Do we have any geologists in the room? Take this prompt in any direction you would like.
40 votes -
What animal or insect going extinct would have the greatest impact on the ecosystem?
Curious on some replies here. I always hear having bees go extinct would be horrible for us. Curious if that’s the worse?
36 votes -
I am a cosmologist, AMA
Ok ok disclaimer, I am a cosmology PhD candidate, don’t have the degree yet. However I do feel comfortable at this point calling myself a cosmologist (I think for the first time ever). In any...
Ok ok disclaimer, I am a cosmology PhD candidate, don’t have the degree yet. However I do feel comfortable at this point calling myself a cosmologist (I think for the first time ever). In any case, with all the new people here, I think an AMA might be fun. I will try my best to answer all of the questions I get asked, but it may not happen quickly!
A bit about my research. I study the conditions in the early universe, specifically when the cosmic microwave background was forming, and I use CMB data to test our understanding of this era. The CMB formed roughly 300,000 years after the big bang, when the universe was 1/1000th its current size. The patterns that we see in the temperature fluctuations of the CMB can tell us a lot about the universe at this early time, and specifically we can try to use them to see if anything ‘unexpected’ happened at this time, like a hitherto undiscovered particle annihilating into ‘normal’ particles (for example).
Ask me anything about the early universe, or physics writ large, and I will do my best to answer!
51 votes