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by dr_dshiv 491 days ago
Neutrinos “interact with regular matter so rarely that it's estimated you'd need about a light-year of lead to completely block a bright source of them. Every one of us has tens of trillions of neutrinos passing through us every second, but fewer than five of them actually interact with the matter in our bodies in our entire lifetimes.”

They have 1/500,000 the mass of electrons. They interact only through the super short range weak force (and gravity). Nearly 5% of fission energy is expressed in neutrinos.

And, they may be their own antiparticles, meaning they can potentially annihilate each other.

Wild that these things can carry so much energy!

3 comments

>Every one of us has tens of trillions of neutrinos passing through us every second, but fewer than five of them actually interact with the matter in our bodies in our entire lifetimes.”

Oh, but those five...

Next time I trip over nothing I am blaming those "darn neutrinos messing up my knee!"
The funny thing is a km^3 scale detector like km3net or icecube has roughly the same mass as all humans combined
Equally hilarious, the Kalgoorlie Super Pit has a volume of 3.15 cubic kilometers.

That's a single, albeit large, gold mining pit and a fraction of the even greater volume excavated by humans looking for shiny stuff.

We mine about a cubic mile of oil every year (https://en.wikipedia.org/wiki/A_Cubic_Mile_of_Oil). That’s 4 km³.
These rare interactions with matter are also a cause of concern in voting machines, right? Or at least it was a concern at one point. A random bit being flipped or something.
It is mostly a problem of DRAM memory cells, though theoretically with enough energy it could flip SRAM cells to or override the driver of a given wire. It is not specific to voting machines.

But the main source is from cosmic rays and local radiation sources in the ceramic packaging and/or decaying elements in the metal frame/leads/solder.

Other types of particles interact much more frequently. But yes: bits do get flipped (even with ECC memory).
Interesting "fact" - The total amount of lead in the universe is a somewhat less than a cubic light year.
How could we possibly estimate that if we don't even know the size of the universe?