This deprives the upper jaw and mid-face of critical support, allowing gravity and external forces to gradually reshape facial structures downward and inward. Over time, the muscles that should ...

This deficit relative to pressure farther away at the same altitude creates a pressure-gradient force that pulls air inward to fill the space vacated by the rising, buoyant air. The reverse ...

As the dying star burns through the last of its fuel, the inward force of gravity begins to overpower the outflow of radiation, compressing its core into denser and denser states. Atoms are ...