I know evolution is governed by chance and it is random but does it make sense to “ruin” sleep if there’s light? I mean normally, outside, you never have pure darkness, there are the moon and stars even at night. In certain zones of the Earth we also have long periods of no sunshine and long periods of only sunshine.
I don’t know if my question is clear enough but I hope so.
Bonus question: are animals subject to the same contribution of light or lack of it to the quality of sleep?
Full darkness is most certainly a thing and is more of a thing then light…light is artificial. Remove the sun…what do you get, full darkness. Light is added, darkness isn’t.
Same with heat…everything is cold unless heat is added.
Cold and full dark are forever, heat and light are techcially temporary.