Editing Openai/6946e998-79f0-8007-9a65-19828450838d (section)

==== Let’s do a simple, pessimistic-but-not-crazy thought experiment: ====
'' Assume only FGK stars count, and they are ~10–20% of stars. Call it 0.15 × N_''.
'' Let N_'' ≈ 10¹¹ stars in the Milky Way → FGK stars ≈ 1.5×10¹⁰.
* Take η⊕,rocky,conservative ≈ 0.1 per FGK star after all your cuts.

Then:

N“good” HZ rocky planets≈1.5×1010×0.1≈1.5×109N_{\text{“good” HZ rocky planets}} \approx 1.5\times 10^{10} \times 0.1 \approx 1.5\times 10^9N“good” HZ rocky planets≈1.5×1010×0.1≈1.5×109
So even under:
# Conservative HZ boundaries,
# Strict radius cuts focused on truly Earth-like sizes,
# A highball “hidden mini-Neptune” subtraction,
# Ignoring (or heavily discounting) M dwarfs,

you still land at hundreds of millions to ~a billion “geometrically and bulk-composition-wise promising” planets in the Galaxy.

If you relax any of those pessimistic assumptions even a bit (include some fraction of K and M stars, allow slightly larger radii, use mid-range η⊕ instead of lower end), you go right back up into the several-billion to tens-of-billions range.