this post was submitted on 15 Sep 2025
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[โ€“] Unusable3151@lemmy.ml 14 points 1 day ago (2 children)

There is a dust layer in the ice at the South Pole about 2km under the surface that interferes with about 5000 photomultiplier tubes spread out over a cubic kilometer in the ice that are watching for light created from high energy muons moving faster than the speed of light in the ice that were in turn the result of the very rare chance of a high energy neutrino interacting with the nucleus of a single atom in the ice.

[โ€“] setInner234@lemmy.ml 4 points 19 hours ago (1 children)

Just want to make sure I am understanding this correctly: Faster than the speed of light, within the medium, right? So the neutrinos are a bit like Cherenkov radiation. But not actually faster than the speed of light, since if that was happening, my world view was just revised rather abruptly :)

[โ€“] Unusable3151@lemmy.ml 5 points 15 hours ago

You're correct! It is Cherenkov Radiation; specifically from the muon (or electron or tau) that is a result of the neutrino interacting with the nucleus of an atom because Cherenkov Radiation happens with charged particles.

[โ€“] PearOfJudes@lemmy.ml 1 points 1 day ago (2 children)

I thought dust was human skin cells? What is this dust layer

[โ€“] ripcord@lemmy.world 1 points 7 hours ago

There's, uh, lots of different kinds of dust.

Also that one is mostly a myth.

[โ€“] Unusable3151@lemmy.ml 2 points 15 hours ago

mineral aerosols.

here is a recent paper trying to figure out the composition from ice core samples for a given age range and location

https://pubmed.ncbi.nlm.nih.gov/37061058/