Phrases I did not expect to see today, or indeed ever, but did in fact see today:
"Opaque to neutrinos"
@starkatt A question on astronomy stackexchange about what the hottest observable thing in the universe is, explaining that the core of a neutron star is unobservable due to being opaque to neutrinos.
@Felthry Wait, is that hotter than the sources of gamma ray bursts?
@starkatt We don't know, because it's unobservable!
@Felthry "50 billion K"
jeepers.
@starkatt gigakelvin!
@Felthry neutrino astronomy is just so wild.
"yeah uhh we're gonna go build a gigantic array of detectors under a couple of kilometers of ice at the south pole. Y'know, to learn about the sky.
"Oh and if we get signals that are coming from upwards, we don't actually want those, because they're from local sources. The neutrinos we actually care about are gonna travel through the entire rest of the planet first."
@Felthry stellar physics, or some other context?