LearnPlanetary scienceNaked eye
Albedo
The fraction of incident sunlight a surface reflects rather than absorbs.
Why it matters
It decides both how bright a world looks and how warm it gets. Venus reflects nearly 70% and is still the hottest planet, because of what its atmosphere does with the rest.
In practice
Enceladus reflects almost everything that hits it, which is why a moon 250 km across is visible at all.
Rests on
Nothing. This is a starting point — you can begin here.