If we see tracks in bubble or Wilson chamber, it means that particles are everywhere and can leave tracks in gases and liquids. They can also penetrate concrete of the building levels in the lab. So they definitely penetrate our brains, retina, optic nerve and so on. But why don't we see any flashes or glitches, related to these particles? I heard astronautes can see something, but why doesn't it comnon down here? Do we have some physiological protection for this?