Fermi estimates are heuristics to outline an approximate solution to complex problems. Fermi estimation is a gem of a skill; it is cheap, fun, generalisable, cumulative & extremely useful with a marginal onslaught of diminishing returns.

My own approach, when reading hard sci-fi, is to fermi estimate some of the technicalities (size, distance, speed, energy, etc.). This is a short investment with an asymmetric return; an excellent catalyst for increasing the absorption spectrum of the narrative.

Below I’ve scratched some of my spontaneous musings. These are rough, first-order estimates. I make a conscious effort to pull the numbers out of my a— thin air, but sometimes I might lookup a general fact (e.g. the mass of Jupiter). Although, I am making a conscious effort to reduce that.

I don’t see how these notes won’t be utterly useless to you. Unless you’re trying to improve your skill & wish for a reference titled “fermi estimates by dummies”.

If it be thy wish to gain this power, thee may seek

Fermi Estimates - LessWrong