Many believe cracking knuckles leads to arthritis or joint damage. But scientists now say the popping sound comes from gas bubbles forming inside the joints, not bones grinding. A 2015 study using MRI showed that stretching the joint lowers pressure and creates a gas-filled cavity. This cavity collapse causes the characteristic crack. Greg Kawchuk from the University of Alberta explained, "As the joint surfaces suddenly separate, a cavity is created and that event is what’s associated with the sound." The older idea that noise comes from bubbles collapsing has been overturned. What about damage? Dr. Donald Unger tested this by cracking only his left hand knuckles for 50 years. His right hand was untouched. He found no difference in arthritis or joint problems. His work won an Ig Nobel Prize in 2009. Other studies echo these results, showing habitual crackers have normal grip strength and healthy cartilage. Although the force in cracking joints is strong, it does not cause lasting injury. Why do myths persist? Since 1947, explanations of the crack sound varied, allowing myths to grow. Research confirms that joints need time before they can be cracked again. The gas must dissolve back into the joint fluid first. Current evidence says knuckle cracking won’t enlarge hands, thin cartilage, or cause arthritis. Joint pain deserves attention, but the crack sound itself is harmless. Science shows that many everyday habits are less scary than the stories say.