I love it when I'm halfway through something and take a second to pause and wonder why someone put so much effort into it, and them I appreciate that they did. This is amazing.
One thing that surprised me the first time I learned it is how 'dense' air is under normal circumstances. The 'mean free path' is the mean distance that a particle travels before changing velocity (typ due to collision). The mean free path of atmospheric air at standard pressure is ~65 nanometers, with ~2x10^19 (20 billion billion) molecules per cubic centimeter experiencing about 10^33 collisions per second. This is roughly the volume of an adult's ear canal.
Whilst I imagine he'd produce content regardless of income, he does have a slightly successful Patreon. To encourage this effort, consider supporting him in some form, if you don't.
I was able to reach 10^-7 mbar with a good vacuum system and I though I would have few thousand molecules, turns out there is a billion (10^9) molecules per cubic centimeter at that vacuum level.
And yet somehow, as far as we know, the energy of every molecular collision is faithfully preserved during a supernova, when effectively the entire volume of a star collapses into its core in less then a second.
That's not accurate. Only the inner core collapses (hence the "core-collapse supernova"; there are also other types), the rest rebounds, is heated up by core-produced neutrinos, and gets ejected. The Wikipedia article is a good start, also there are plenty of good papers on arxiv (e.g. on still-not-too-successful numerical modeling of the aforementioned "heating", without which the thing simply doesn't go bang).
One thing that surprised me the first time I learned it is how 'dense' air is under normal circumstances. The 'mean free path' is the mean distance that a particle travels before changing velocity (typ due to collision). The mean free path of atmospheric air at standard pressure is ~65 nanometers, with ~2x10^19 (20 billion billion) molecules per cubic centimeter experiencing about 10^33 collisions per second. This is roughly the volume of an adult's ear canal.