Why do sunsets and sunrises look so different? Isn’t it technically the same thing?
In: Earth Science
Here’s [an article on that exact subject](https://www.livescience.com/34065-sunrise-sunset.html).
The key excerpt is the following:
>All “twilight phenomena” are symmetric on opposite sides of midnight, and occur in reverse order between sunset and sunrise, the authors note in “Color and Light in Nature” (Cambridge University Press, 2001). That means there’s no inherent, natural cause of a major optical difference between them.
In short, in the absence of other factors (increased pollution through the day, etc) there is no real natural difference, but there may be a difference is in the observer’s awareness of the time of day and your body’s physiological response as well. For example, your eyes may be more sensitive in the morning due to being dark adapted, so your perception may be a bit different than it is in the evening.
The one thing that *is* different between sunrise and sunset is the angle at which the sun leaves/approaches the horizon:
>According to the astrophysicist Neil Degrasse Tyson, director of the Hayden Planetarium in New York, there’s also a trick for distinguishing a sunrise from a sunset played in reverse. Because of Earth’s tilt, the sun doesn’t rise or set along a vertical line, but at an angle. “When viewed from all latitudes north of the Tropic of Cancer (23.5 degrees north latitude), the sun always rises at an angle up and to the right, and sets and an angle down and to the right,” Tyson writes on his website. “That’s how you can spot a faked sunrise in a movie: it moves up and to the left. Filmmakers are not typically awake in the morning hours to film an actual sunrise, so they film a sunset instead, and then time-reverse it, thinking nobody will notice.”
The difference is in the location. Your sunrise comes from behind the picturesque mountains to the east, while your sunset dips below neighbor Cletus’s run-down work shed.
I want to add to some of these answers as a gas phase chemist:
The composition of the atmosphere at each level is different in the evening vs. the morning. The sun having been out all day drives a ton of complex chemical reactions in the atmosphere – so by the time the sun sets, there’s an entirely different mixture of chemicals in the air than when it comes up.
That’s not the whole story but it does cause some of the differences.
The color of the sky is from a phenomenon called Rayleigh scattering. The simplest explanation is that the sky color is affected by the angle of the light. The way you can hold a prism in a light beam and make rainbows on the wall or other colors. Gases in our atmosphere do the same thing with light from the sun. Change the angle and you change the color. That is why you have different colors at different times of day and different times of year.
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