The slowest variable?
The alpha “constant” in astro-physics seems to vary across the universe. The author comment:
Earth sits somewhere in the middle of the extremes for alpha. If correct, the result would explain why alpha seems to have the finely tuned value that allows chemistry – and thus life – to occur. Grow alpha by 4 per cent, for instance, and the stars would be unable to produce carbon, making our biochemistry impossible.