“We don’t cater to jokes that displace causality here,” says the bartender.
BBS member walks into a bar.
I love BB because it shows me cool and interesting content from cool and interesting people who I then follow and learn even more cool and interesting things.
It’s not really an important difference; the future and past light cones stay the same but assignment of time coordinates to anything outside them is relative. If it is going faster than light in some reference frames, then in others it will be going faster than light plus backward in time. Of course, a neutrino going through a bar would still have to turn around somehow to get back to the bar’s past.
Also, neutrinos don’t go faster than light in vacuum and in fact are expected to go slower than it, but that’s probably beside the point.
can it turn? - what force could act on it?
I wasn’t really thinking of a mechanism, but gravity would deflect them as it does light – you would get noticeable gravitational lensing of both around something like a black hole. They’re also affected by the weak force, though that’s less of a turn because it alters the particles; the way we detect neutrinos is by waiting for one to get changed into an electron.
Also, just in case anyone is worried about not having enough bizarrely technical puns in their life:
right, and i suppose the detectors detect them, so they interact with something - but can’t they go through thousands of miles of lead without hitting anything? - would take a shit ton of gravity and a very large distance to turn that thing - rather a large bar, wouldn’t it be? - it could go outside and turn around in the parking lot, if the parking lot had a black hole in, maybe
The weak force. And Gravity.
A faster-than-light neutrino passes through a bar, travels out of the galaxy and near to a supermassive black hole, which flings it around. In an astonishing coincidence, this causes it to pass back through exactly the same bar, what works out to be only a few seconds earlier.
This miracle passes unnoticed by the bartender, who can’t see the neutrino and is busy discriminating against talking mushrooms and strings.
that’s the bar! - hang on, here come my friends the rabbi and kangaroo - won’t you join us?
Thank you. Didn’t take you nearly as long, and you actually answered the question “What is a neutrino.” Good job.
OMG! Thank you. That makes so much more sense! I thought I heard someone call them Wolfgang Pauli’s beekeepers.
Glad I could help.
Well, since you said “next question”: What’s a relic neutrino?
Hmm. Not all that long ago, it was “Your mother’s like a bowling ball; we put our fingers in her holes and roll her down alleys.”
Aparently neutrinos that decoupled from the rest of matter early in the universe as it cooled.
And what I’m really wondering: why are they so much less energetic than other neutrinos?
