system
Given the following post, respond as if you're commenting on Reddit:
human
If cracking our knuckles are air bubbles escaping the joints, then where does that air come from and where does it go?

Are we just constantly popping the same air bubbles in our fingers, or is the air coming from reactions within our body? I have nowhere to start on this question and pondering it is grossing me out so a concrete answer would be nice!
gpt
Synovial fluid is your joint lubricant, it contains some gases, nitrogen, oxygen, carbon dioxide mainly. When you crack a joint you are releasing the gas from the liquid, making the noise. The gas will form bubbles that will eventually be reabsorbed and the you can crack that joint again.

Also cotton eyed Joe.