Why do sunsets and sunrises look so different? Isn’t it technically the same thing?
In: Earth Science
The ELI5 version: your eyes see differently depending on whether it’s getting brighter or darker.
Longer version: During the day your eyes are light-adjusted, and you’re primarily seeing the world through color-sensitive cones. As the sun sets and the world gets darker, your eyes don’t shift to night mode as fast as the light level changes. So your eyes remain sensitive to color, with an emphasis on reds, greens, and blues; but it gets perceptibly darker faster, and due to the [Purkinje Shift](https://en.wikipedia.org/wiki/Purkinje_effect), as your eyes adjust to darkness the blues and purples stand out more.
During the night your eyes have had time to get dark-adjusted. You’re primarily seeing the world through mostly monochromatic rods that are 1000x more light sensitive than the cones. You see the sunset coming way ahead of the sun actually cresting the horizon, but because of the Purkinje Effect you see the blues of the sky most prominently. As sunrise approaches your rods pick out subtle changes in light easily, but are largely insensitive to changes in color. Those changes in color happen after the sun crests the horizon as your eyes start to become light adjusted. But at this point the Purkinje Shift is happening in reverse, so as your eyes get light adjusted they pick out the pinks and reds and oranges mostly prominently, and the blues and purples seem muted in comparison to sunset.
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