system
Given the following post, respond as if you're commenting on Reddit:
human
Why can you see fog in the distance, but not right in front of you?

I always wondered, why 50m+ near me I can see the fog, but not closer to me.
gpt
Fog is water particles in the air. When you’re looking in front of you, you notice the particles in a low volume (just in front of you). When you look in the distance you observe a higher volume and by extension a higher number of particles. The higher number becomes noticeable and you”see” the fog.