http://physicsworld.com/cws/article/news/2011/mar/02/neutron-star-has-superf... http://www.nasa.gov/mission_pages/chandra/news/casa2011.html

On Tue, Jun 24, 2014 at 11:50 AM, Warren D Smith <warren.wds@gmail.com> wrote:

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Cores of neutron stars are in a superfluid state. -- Mike Stay - metaweta@gmail.com http://www.cs.auckland.ac.nz/~mike http://reperiendi.wordpress.com

--is there any actual evidence for this? Seems to me it is a rather wild extraordinary claim, requiring extraordinary proof. And while I am at it, another question is this: many neutron stars (e.g. pulsars, magnetars) are claimed to have enormous magnetic fields. (And there actually is evidence for that.) Isn't this incompatible with the claim of superconductivity? If the earth had a superconductive core, what would happen about the magnetic field of the earth?

--Supposedly, observations of the 330-year-old (?) neutron star Cassiopeia A by Chandra X-ray observatory show the "critical temperature [for superfluidity] is between one half a billion to just under a billion degrees Celsius." They supposedly deduced this because the neutron star cooled by 4% over the last 10 years, a remarkably large cooling. The claim the star is 330 years old is somewhat dubious, or anyhow lacking in accuracy, because there was no historical record of the supernova. The neutron star itself was only discovered in 1999. QUOTE: "A wide region of the neutron star is expected to be forming a neutron superfluid as observed now, and to fully explain the rapid cooling, the protons in the neutron star must have formed a superfluid even earlier after the explosion. Because they are charged particles, the protons also form a superconductor." This makes no sense to me at all. Suppose you had a glass of water, which was, as you observed it, gradually changed into ice. Would you observe a 4% drop in temperature thus "proving" the phase change to ice occurred? NO. Au contraire, you would observe a STATIONARY temperature, refusing to drop, thus proving the phase change occurred. So it seems to me, what they have actually "proven" is the LACK of super-ivity, if anything. What the hell is the matter with them? Reading more, QUOTE: "copious numbers of neutrinos - nearly massless, weakly interacting particles - are created as the core temperature falls below a critical level and a neutron superfluid is formed, a process that began about 100 years ago as observed from Earth. These neutrinos escape from the star, taking energy with them and causing the star to cool much more rapidly." Oh. Well, that made sense, but it proves absolutely nothing about the superfluid character of anything, it merely indicates that neutron synthesis is happening inside the star, which is something everybody already knew. Searching more, I find the following papers on arXiv: http://arxiv.org/abs/1302.6626 http://arxiv.org/abs/1110.5116 Am I convinced by these papers that there is super-ivity going on? No. It seems like an interesting possibility, but a long way short of something that'd convince me. Also, the whole BCS theory of superconductivity has as far as I can tell been a total failure if you measure "success" as "the ability to predict transition temperatures." As far as I can tell, transition temperatures vary between about 150 kelvin and microkelvin in matter so far observed (and probably much wider if they could make more observations) which is pretty damn unconvincing to me re their ability to predict what is going to happen inside neutron stars. So I'd call this all "wild speculation."