Comment by paimapi
3 hours ago
>Neutrinos give us a pristine snapshot into the origin of the universe. They have travelled billions of years and trillions of miles without interacting with anything. Unless...we catch them!
I assume this is not a hard, totalizing law since it seems we're able to get samples of neutrino collisions in just a kilometer sized chunk of ice on Earth (meaning that the probability of collision is not absolutely zero and there's no way to know the full neutrino travelogue through the universe)
Correct, they do have a probability of interacting, but it's extremely low, depends of the energy of the neutrino (its momentum) but basically it can go through 1 light year of lead and still have only a 50/50 chance of interacting.
to put things to scale 1 ly is 9,460,730,472,580,800 meters, or 63,241.077 astronomical units, the distance from the Earth to the Sun.
Needless to say, it's pretty weakly interacting as far as interaction goes...