The Presidential Daily Brief


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    Scientists Discover Mechanics Behind Knuckle Cracking

    They’ve cracked the case. After more than six decades of research, scientists might finally have an answer to what causes that popping sound when people crack their knuckles. When medical imaging wasn’t accurate enough, researchers turned to mathematical modeling, which suggested the sound is the partial collapse of microscopic bubbles in joint fluid — and the only factor that impacts the level of sound is the force applied to the knuckle. Now physiologists hope the research could give insight into how healthy joints function, and aid with preserving their mobility.

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