TODO why did Python kill it? They are very similar and existed at similar times, and possibly Perl was more popular early on.

Perl likely killed Tcl.

Ciro Santilli finds it interesting that radioactive decay basically kickstarted the domain of nuclear physics by essentially providing a natural particle accelerator from a chunk of radioactive element.

The discovery process was particularly interesting, including Henri Becquerel's luck while observing phosphorescence, and Marie Curie's observation that the uranium ore were more radioactive than pure uranium, and must therefore contain other even more radioactive substances, which lead to the discovery of polonium (half-life 138 days) and radium (half-life 1600 years).

Uranium emits them, you can see their mass to charge ratio under magnetic field and so deduce that they are electrons.

Caused by weak interaction TODO why/how.

The emitted electron kinetic energy is random from zero to a maximum value. The rest goes into a neutrino. This is how the neutrino was first discovered/observed indirectly. This is well illustrated in a decay scheme such as Figure "caesium-137 decay scheme".

The half-life of radioactive decay, which as discovered a few years before quantum mechanics was discovered and matured, was a major mystery. Why do some nuclei fission in apparently random fashion, while others don't? How is the state of different nuclei different from one another? This is mentioned in Inward Bound by Abraham Pais (1988) Chapter 6.e Why a half-life?

The term also sees use in other areas, notably biology, where e.g. RNAs spontaneously decay as part of the cell's control system, see e.g. mentions in E. Coli Whole Cell Model by Covert Lab.

Ciro Santilli once visited the chemistry department of a world leading university, and the chemists there were obsessed with NMR. They had small benchtop NMR machines. They had larger machines. They had a room full of huge machines. They had them in corridors and on desk tops. Chemists really love that stuff. More precisely, these are used for NMR spectroscopy, which helps identify what a sample is made of.

Basically measures the concentration of certain isotopes in a region of space.

Gun-type fission weapons are the simplest approach and they work with Uranium-235 bombs as you can ignite it with just one explosion.

But Gun-type fission weapons don't work with plutonium, and weapon grade Plutonium is cheaper than weapon grade Uranium, so it wasn't much used.

Implosion-type fission weapons are more complicated than gun-type fission weapon because you have to precisely coordinate the detonation of a bunch of explosives.