system
Given the following post, respond as if you're commenting on Reddit:
human
Why does the color of the sky get lighter, the closer it is to the horizon?
gpt
It is because of so called "Mie scattering" of sun light in the haze, contained in lowest layers of athmosphere.
The light passing through the haze changes its direction to random other directions. So, it catches light from sun and directs some of it towards your eyes.

When you look up, the layer of the haze is pretty thin and does not significally affect color of the sky.
But when you look to horizon your look goes through about 5 km full of the haze, and your eye catches all that scattered light.