I honestly don’t understand why everyone uses exponential curves for their models when sigmoidal curves seem to better model reality for lots of phenomena: population growth, language change, diffusion of innovation… and perhaps even the growth of capitalist economies.
There’s really no point in pandering to white supremacist neo-Confederates in the 21st century because there’s no chance they’ll vote for a Democrat anyway
I was enamored by the myriad fates of dying stars.
Stars with core temperatures around 15 million Kelvin or less (like the Sun) convert hydrogen to helium via the proton-proton chain reaction.
In time, the hydrogen in the core will run out, and the core will collapse due to gravity. This will cause the outer layers to heat up and expand, transforming the star into a red giant.
While nickel-56 can fuse with helium to form zinc-60, because the helium comes from photodisintegration of other heavy nuclei (the original helium of the star already having been mostly consumed by carbon burning), it is a net endothermic process.
So fusion basically ends with iron.
The most abundantly synthesised nuclei in these conditions turn out to be nickel-56 and the unstable α nuclei beyond calcium (titanium-44, chromium-48, iron-52, and zinc-60). This is perhaps the most beautiful result in the whole theory of nucleosynthesis, for it shows that iron, used in railways and haemoglobin, the king of nuclear creation, one might say, is not actually produced as iron, but in the form of radioactive nickel.
I know Elon Musk and others are working on it, but remembering this tragedy also makes me feel especially sad that the U.S. doesn’t have independent human space flight capability right now.