system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If there is no erosion on the moon, how is there dust on the surface?
gpt
take a rock.   bash it with a meteor going 10000mph.   you get smaller rocks.    take smaller rocks.  bash it with a meter going 100000mph.   get even smaller rocks. 

repeat that a million years.   you get dust.