Props for her husband who's been incredible of taking care of her.
Hopefully she maintains a higher baseline from here on out and the production of these videos doesn't produce further Post Exertional Mailise that could worsen her condition.
The tank's cross sectional area relative to the sun depends on its relative orientation to the sun. We'll ballpark it at somewhere between its circular endcaps (Pi x ((39.3/2)^2) = 1213 square meters) and its curved cylindrical face (which, pointed right at the sun, has a rectangular cross section of 41.4 x 39.3 = 1627 square meters).
So, conservatively, the neutrino flux through Super-K's tank is 1400 m^2 x (100cm/m)^2 x 6.5e10 neutrino/second/(cm^2) x 86400 seconds/day = 7.86e22 neutrinos/day passing through the tank. Of which 30 are detected.
[1] https://en.wikipedia.org/wiki/Super-Kamiokande
[2] https://en.wikipedia.org/wiki/Neutrino (end of intro section, just before History). Wikipedia says only that the "majority" of the 65 billion flux is from the sun, so we might be off by a factor of two-ish in the worst case.
i want to be more appreciative every day for my health post-covid... not everyone was so lucky, and I can only imagine the gut-punch it is to know everyone went through a thing, but you got singled out for some perpetual daily punishment :'(
This is because the electromagnetic energy of the supernova can take hours to force its way through all the star's mass to the surface when the core dies, but the gravitational crush turning protons and electrons into neutrons releases a massive burst of neutrinos in every direction. And the neutrinos are so weakly-interacting with the matter in the star that they get out first. Then, a million years later, arrive in our solar system at such a high fraction of lightspeed that they presage the coming electromagnetic shock-front because the constant difference in escape time between neturinos, which are particles of matter, getting out of the star without interacting with anything and the electromagnetic waves moving through the star's matter at a fraction of lightspeed created a gap that the light never caught up to.
The universe is a profoundly wild place.
I’m today years old learning that the light that we actually see on earth today came out 100s of thousands of years ago.
1. There’s a sort of diffusion process going on. Photons from the core have some mean free path as a function of radial position (and, obnoxiously, of wavelength as well, so maybe we ignore that). You could calculate the mean time for a hypothetical object emitted from the core and traveling according to those mean free paths to escape.
2. You could imagine you have marked a photon and watched it travel. This is quite problematic. First, photons in thermal equilibrium obey Bose-Einstein statistics because they are indistinguishable bosons, and anything that could mark them would change the statistics to that of distinguishable particles. But whatever, the temperature is high and maybe this doesn’t matter. Also never mind that those core photons are mostly much shorter wavelength than the photons we see. But you can still imagine. (The answer is probably quite similar to #1 since this is sort of the same problem depending on how you think about the interactions with matter in the sun.)
3. You could calculate how long it would take to notice anything if the core suddenly stopped fusing.
However, as the photon collides with other particles during its random walk, some of its energy is transmitted to those other particles. Sometimes a collision transfers energy to it too.
In a simple model, the energy that originally belonged to the photon gets transmitted from particle to particle through convection, and can escape the star through radiation long before the original photon reaches the surface. I don’t think that model is supposed to be physically accurate, rather to be an illustration about the convention process inside a star.
Edit: on another note, way to go on your recovery Diana. We've been rooting for you.
Construction is underway on the next version of the experiment "Hyper-Kamiokdande" which is similar in design but significantly bigger. If I recall correctly Hyper-K will be two 200 kilo-tonne detectors, compared to Super-K which is a measly 50 kilo-tonne detector.
Her back catalog is good and you still get paid for people watching your old videos.
And for terrestrial sources (geoneutrinos) from natural and artificial sources, there are/were efforts that could detect terrestrial reactors in operation like AGM2015. [1] Irrespective of the current geopolitical instability, I'm surprised that the IAEA doesn't have its own network of geoneutrino detectors to proactively look for proliferation concerns.
0. https://neutrino-map.science/ (ICNO)
1. https://www.nature.com/articles/srep13945 (KamLAND and frmr Borexino)
After seeing her status updates 2 years ago I was honestly really concerned she would be gone for good. It sounds like she had a serious case of myalgic encephalomyelitis brought on by Covid.
Part of why we know so little about these types of conditions is they are incredibly unfair. Women are 4x as likely to have some sort of constant fatigue disorder as men, and you see this reflected in literature going back centuries when describing women who just flat out disappear from public life.
One of the things about being bedridden for a long period of time is that there is a high risk of becoming more or less permanently bedridden. Especially if you have a chronic fatigue syndrome, you become weaker and any activity can retrigger fatigue. So her pushing herself to make new content sustainably is important very encouraging.
Thirty interactions on average per day, that's crazy - earlier in the video the host mentions that the cross section of a thumbnail has a billion neutrinos flowing through every second!
The uncertainties about the masses of the various kinds of neutrinos are very high.
Also their abundance in the Universe is much less accurately known than for electrons and nucleons, because many processes generate neutrinos or antineutrinos and only few of those are absorbed in later collisions, so the total amount of neutrinos and antineutrinos is increasing continuously, even if the difference between the number of neutrinos and antineutrinos varies only little.
For the mass of nucleons and electrons one can make reasonable estimates, even if the uncertainties about the densities of interstellar and intergalactic matter are also very high. On the other hand, for the mass of neutrinos + antineutrinos the uncertainties encompass many orders of magnitude.
The detectors of neutrinos can detect only high-energy neutrinos. There may be much more undetectable low-energy neutrinos.
Between things like black holes and neutrinos I wonder how much Dark Matter will end up being dark matter. And I think the cosmological crisis indicates we are measuring space curvature wrong somehow.
Like neutrinos interact with gravity, which means they can be lensed, and ejected from pulsar and black hole jets. And particles moving faster than visible matter would pass that matter and accelerate it, increasing blue shift and decreasing red shift the farther you are from the source.
However, looking for sources relating to leaching by ultra pure water (UPW) not much turned up.
I did however find on Google Scholar a paper "Ultrapure Water: friend or foe?"... which lead me to https://www.balazs.com/sites/balazs/files/2023-03/pub0039-up... . Reading between the lines, Marjorie Balazs appears to have made a career out of UPW; she says in that paper:
"The ability for UPW to absorb and dissolve or react with all kinds of materials complicates other aspects concerning its use in the processing of wafers."
Seems like UPW dissolves anything, so lends credence to the anecdote.
Interesting topic, hadn't thought about UPW for wafer fabrication before.
https://www.businessinsider.com/super-kamiokande-neutrino-de...
It's the reverse problem: because the water is so pure it easily gets contaminated by minor things. So all the equipment has to be carefully cleaned.
From the closing of the first graph in the Wiki for water: Due to its presence in all organisms, its chemical stability, its worldwide abundance, and its strong polarity relative to its small molecular size, water is often referred to as the "universal solvent"
https://en.wikipedia.org/wiki/Water
Edit: after enough searching I was finally able to find this article [0] that I was originally trying to find. The leaching part was right, but the bleaching part looks to have been as misremembered
[0] https://www.businessinsider.com/super-kamiokande-neutrino-de...
The chain reaction escalated uncontrollably, and within ten seconds, approximately 6,800 of the 11,129 PMTs were destroyed.
[1]: https://physicscommunication.ie/neutrino-detector-in-peril-t...
https://www.youtube.com/watch?v=vqeIeIcDHD0
(caution for those currently sick as it's a rough watch at first)
Seems like someone's having difficulty with object permanence. The Sun doesn't actually disappear at night.
