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| Source - xkcd Rollover text - Unlike an Iron Age collapse, a Bronze Age collapse releases energy, since copper and tin are past the iron peak on the curve of binding energy. |
...so, it's funny because...
We haven't taught nuclear decay or nuclear chemistry in my first year chemistry class at Princeton in quite a few years since it was taken out of the Ohio chemistry curriculum and off of the AP exam quite a few years ago. We leave that nuclear stuff to the PHS physics department.
With all that being said, I remember the top row of decay mechanisms, and they're real.
- Alpha decay sees the nucleus shedding two protons and two neutrons.
- Beta decay shows a neutron turning into a proton while the nucleus ejects an high-energy electron, aka a beta particle. That drawing helps us to know that Randall is drawing neutrons as shaded-in circles and protons as the 'white' or 'hollow' spheres.
- Gamma has the nucleus rearrange its particles - protons and neutrons, known collectively as baryons (though there are more baryons than just protons and neutrons.)
- Electron capture is just what it says: an electron is drawn into the nucleus, turning a proton into a neutron.
- Positron emission is also a proton turning into a neutron, but in this case it releases a position, effectively an electron with a positive charge.
- Neutron emission is pretty self-explanatory as a neutron leaves the nucleus.
Then we get to the made-up ones which lead to the jokes. For some of these, I did rely on explainxkcd to get the gist.
- Baryon panic would be insanely energetic, requiring all of the protons and neutrons to spontaneously separate, requiring a massive amount of energy to be absorbed by the nucleus.
- Omega decay is the assumed progression of alpha, beta, and gamma decay - omega being the last Greek letter in the alphabet. I guess since alpha, beta, and gamma decay give off increasingly energetic particles, omega decay would somehow give off the most energetic particle and cause death?
- Electron wilt seems to show the electrons just stopping their motion around the nucleus, wilting like a flower.
- One big nucleon shows all of the protons and neutrons 'congealing' into a single nucleon, the generic term for a particle in the nucleus. The is, I guess, kind of like a Bose-Einstein condensate but for the nucleus.
- Fungal decay gets nuclear decay and biological decay muddled up with the nucleus sprouting mushrooms.
- Collapse due to invasion by the sea peoples seems to refer to something that supposedly happened to the eastern Mediterranean during the late Bronze Age. I dunno. I had to look it up.
The rollover makes reference to the fact that the nuclear binding energy for iron-56 is the highest on the periodic table (at least among common isotopes). This is why large stars never make anything beyond iron-56 in their life cycle until they go supernova. And since bronze is made of tin and copper - both beyond iron-56 on the periodic table - a collapse of those elements releases energy according to Randall.
It's all some pretty esoteric stuff today.
Don't worry if you don't get it.
