That cracking noise. When you crack your knuckles?
It’s caused by a bubble forming (rather than collapsing) inside the fluid between the joints.
Cecil’s column on this weighty matter.
You should ask the mods to update your Title to include the phrase “knuckle-cracking” so we have a sense of what you are referring to.
Yeah, inveterate knuckle cracker here - passed it on to my kids, for better or worse. Good to see we have clarity on the origin of the sound, if only because I am also hearing that, based on this, there is a better sense that knuckle cracking is not harmful at all. w00t! (Well, I still think doing a hard torque to get a knuckle to crack is still a bad idea…)
Finally solved, over 30 years ago?