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On Pluto, the Sun is 250x more bright than the moon is on Earth. And moonlight (at a full moon) is pretty sufficient for most things you do with your eyes. ht

• Someone 11y ago
  That's because the human eye works across an amazing range of light intensities. https://en.m.wikipedia.org/wiki/Adaptation_(eye)#Efficiency https://en.m.wikipedia.org/wiki/Adaptation_(eye)#Efficiency: "The human eye can function from very dark to very bright levels of light; its sensing capabilities reach across nine orders of magnitude. This means that the brightest and the darkest light signal that the eye can sense are a factor of roughly 1,000,000,000 apart. However, in any given moment of time, the eye can only sense a contrast ratio of one thousand. What enables the wider reach is that the eye adapts its definition of what is black." Pluto is 30-50 AUs from the sun, so ignoring the effects of any atmosphere, there's "only" a factor of 900-2500 more sunlight on Earth than on Pluto (sun vs full moon is 400,000:1 or thereabouts)