Physics Girl: Super-Kamiokande – Imaging the sun by detecting neutrinos [video] (youtube.com)
389 points by pcdavid 9 hours ago
roelschroeven 6 hours ago
Dianna got better sometime last year as well, just in time to fly home to Hawaii for her father's funeral (yeah ...), but she got a lot worse again later. I really hope things will keep going well for Dianna now.
Props for her husband who's been incredible of taking care of her.
PaulKeeble 2 hours ago
This is the nature of ME/CFS (caused by Covid or otherwise), it does vary somewhat over time although the course is not always to improvement or around the same level but sometimes to death. She received some form of experimental treatments in order to gain the prior recovery which was at least a stellate ganglion block, she has not mentioned what else she may have received.
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.
dataflow 6 hours ago
Man... I came here hoping to read she was fine now. Had no idea things got worse again :( I hope things get better for her.
Jeremy1026 5 hours ago
At the moment, she appears to be progressing up. The user you are replying to was talking about a past up-swing followed by a down-swing. Hopefully there isn't a down-swing to follow this current up-swing.
pico303 24 minutes ago
The Neutrino collector bit was interesting, but the best part of this video is seeing the joy in her eyes educating the rest of us about science again.
ayhanfuat 7 hours ago
Such amazing news. She’s been bedridden due to long Covid. Got better a few times but after a while attacks came back. Both she and her husband showed great strength. So happy to see a new milestone.
patcon 7 hours ago
thanks so much for the context. I'm glad if she's reclaiming from her losses <3
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 :'(
oxag3n 16 minutes ago
It's a giant long term project with a fascinating history and engineering. One notable event which is interesting from engineering perspective was a catastrophic failure of roughly half tubes in 2001. It took them five years to fully restore 6K tubes.
dotancohen an hour ago
The video mentions that this image was taken during the night time. If the neutrinos do not interact with the entire Earth on their way through, then how do they interact with the sensor?
davidmurdoch 44 minutes ago
Watch the video
dotancohen 29 minutes ago
Thanks. I watched half the video, but couldn't finish it. Now that I've finished it I see that the neutrinos interact with water in the tank.
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!
jesse_dot_id 5 hours ago
Long COVID is a nightmare. I'm glad she's able to fight it off enough to do the things she loves again.
cleandreams 7 hours ago
Wonderful to hear. Her long Covid was heartbreaking (saw the videos). I hope she gets stronger and stronger! Welcome back!
hinkley an hour ago
Some of my favorite YouTubers have done guest spots on her channel, which made me love them a little bit more.
Her back catalog is good and you still get paid for people watching your old videos.
Brajeshwar 7 hours ago
Welcome back. One of my staple YouTube Subscriptions.
I’m today years old learning that the light that we actually see on earth today came out 100s of thousands of years ago.
gosub100 5 hours ago
It's not the same photon though. The fusion happens in the core, then takes millennia for the energy to escape. During that time photons are emitted and absorbed by the atoms, until the surface emits one that finally travels to the earth in 8 minutes. Anyway that's taking you from the ELI5 to the ELI9 version. I'm sure someone on here can correct it further.
amluto 5 hours ago
I haven’t tried to look up the history of this claim, but here are some guesses:
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.
gus_massa 4 hours ago
mncharity an hour ago
amluto 2 hours ago
teamonkey 3 hours ago
Photons are generated in the star’s core but the core is dense. The photons move around the core, bouncing off other particles, a random walk. It takes a vast amount of time for that photon to escape the sun and reach the Earth, as per monte-carlo simulations of this random walk.
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.
fsh 5 hours ago
Any interaction between light and matter can be modeled as absorption and re-emission (stimulated or spontaneous) of photons. In this picture, there is not much difference between a photon traveling through the sun or through a piece of glass, and the analog makes physical sense. Since photons are massless elementary particles, they are indistinguishable and their number is not conserved. The notion of "the same photon" is questionable in any case.
Hikikomori 5 hours ago
Similar to how infrared radiation works in our atmosphere, minus the timescale?
dylan604 3 hours ago
I think Super-K is the place with water so pure that it will leach pretty much anything which was discovered when one of the tech's hair got wet while leaning over the water. The hair looked bleached after it went into the water. My googlfu is not finding anything to confirm though
pbhjpbhj 2 hours ago
Ha, I had never heard of this effect despite having studied Kamiokande (well neutrinos, at least) as part of a mini-dissertation for my B.Sc.
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.
hi41 29 minutes ago
Reminds me of the scene in Kung Panda 1 where one feather of the goose, Peng, falls into the tunnel which Tai Lung uses to unlock his cage and escape.
hinkley an hour ago
Isn’t that also the one where a sensor imploded and caused a chain reaction that destroyed like a third of the other sensors?
magicalhippo an hour ago
Yes, except about half. This[1] article goes into how and why, without the fluff.
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...
dejongh 5 hours ago
What an amazing storyteller. I will watch many more of her videos. I hope she will make many more videos ♥
jwr 7 hours ago
So happy to see her back! It was a grueling journey and we were all crossing our thumbs, waiting and hoping…
hinkley an hour ago
How much of the mass of the universe is neutrinos?
legitster 5 hours ago
It's really cool to see her back and making videos again.
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.
flux3125 3 hours ago
According to science video thumbnails on YT, nothing should be possible
shadowgovt 4 hours ago
One of my favorite bits of astrophysics trivia is that the neutrino detection experiments serve as an early-warning system for supernovae, to allow astronomers to prioritize telescope time and swing the scopes around to see the first visible-light and radio signals of the event.
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.
olivia-banks 3 hours ago
This is fantastic news! Long COVID is awful, so I'm glad to see that she's recovering, if only incrementally.
alabhyajindal 6 hours ago
BOOM! Let's go
gosub100 5 hours ago
I can't remember where I heard of it, but decades ago there was another neutrino detection center, also in Japan I think, that had those vacuum tube detectors, but care wasn't taken in systems design. One of them broke and the implosion caused the neighbors to break. Leading to a catastrophic of almost all the sensors! I feel bad for them, I'm sure someone here knows the exact name and date. But man, what a tough lesson to learn.
Edit: on another note, way to go on your recovery Diana. We've been rooting for you.
0PingWithJesus 5 hours ago
That was Super-K, the same detector she's talking about in the video. The incident occurred in 2001 and set back the start of the data taking for them quite a bit, they were able to begin data taking by re-distributing the unaffected photo-detectors to cover the gap where the imploded detectors were. Eventually (2005/2006) they replaced all the destroyed photo-detectors and took data from then on out with a full-suite of sensors. Following this incident all Japanese experiments with these types of photo-detectors take the risk of implosion seriously and have mitigation built in to the design. Super-K has been running continously since then with some interruptions for upgrades & maintenance, and is still taking data today (as far as I'm aware).
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.
tomasphan 5 hours ago
It was the same detector that imploded. Mark 2 was then reinforced so it didn’t happen again.
human_hack3r 6 hours ago
Happy to see her back to science!
nickandbro 6 hours ago
Is this long Covid or depression or Major Depressive Disorder (MDD)? Because in her earlier videos she talks about becoming bed-bound again due to her emotional state after finding news her friend who had a similar condition died.
dirck-norman 6 hours ago
As someone who suffers from a complex autoimmune disorder which has caused dysautonomia and suspected mitochondrial dysfunction, stress flares and exacerbates symptoms. This has a physiological basis in the complex way the HPA axis/cortisol affects us at the cellular level. My primary diagnosis is sarcoidosis with small fiber neuropathy, but they don’t fully understand all the mechanisms of auto-immune fatigue and dysregulation.
nickandbro 6 hours ago
Sorry to hear. Thanks for explaining.
nablaxcroissant 6 hours ago
It was essentially long covid. me/cfs or chronic fatigue syndrome induced by covid infection
nickandbro 6 hours ago
Wow, did not know that. Thanks
KaiserPro 6 hours ago
Dunno, personally I don't think its that much of my business. Sure I'm curious, but that doesn't mean I have a right, or that its a nice thing™ to publicly speculate
hinkley an hour ago
She’s been pretty open about it. She even touched on it at the end of this video.
ChrisClark 5 hours ago
I'm quite sure being that terribly sick could cause depression yeah, but that's not the reason
ck2 4 hours ago
video about her long-covid battle and recovery here:
https://www.youtube.com/watch?v=vqeIeIcDHD0
(caution for those currently sick as it's a rough watch at first)
hinkley an hour ago
I know someone whose CFS is about 10% of hers and it was still a rough watch. She got hit really fucking hard.
JKCalhoun 7 hours ago
(Typo in the title.)
danscan 6 hours ago
TIL nobody can spell phyzix
pcdavid 7 hours ago
Fixed
xeonmc 7 hours ago
(should be Psychic Girl)
AlexeyBelov 6 hours ago
As in, knows the future?