system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does a rocking motion facilitate sleep?

Why does the rocking motion like that of a moving vehicle or a rocking chair put me to sleep? Why does this work for babies and also me as an adult? I can even just rock myself and it puts me to sleep - ELI5!
gpt
I imagine that it has something to do with the development of an unborn child in the mother's womb. In what way is it comfortable to sleep? - in darkness, in warmth and with rocking motions, three attributes of the inside of the uterus. You spent the first nine months of your life sleeping inside of there. It's only logical that your subconscious pines for its relative safety and comfort.