the.com/habitable zone
the cosmic goldilocks porch: not too hot, not too cold, just liquid enough for water to stay wet.
means the range of distances from a star where a planet could have liquid water on its surface given the right atmosphere.
from coined mid-20th century by astronomers modeling stellar radiation, popularized as goldilocks zone once the porridge metaphor proved irresistible to journalists.
depends on starbigger star, farther zone, wider too
not sufficientvenus sits inside ours, still hellish
can movestars brighten with age, zones drift outward
atmosphere mattersgreenhouse gases can widen zone dramatically
for instance
earth — comfortably centered in the sun's habitable zone for billions of years
kepler-186f — first earth-size planet found in another star's zone, 2014
trappist-1e — one of three zone planets orbiting a single red dwarf, 2017
proxima centauri b — nearest exoplanet in a habitable zone, 4.2 light-years away