It seems to me all momentum is angular momentum.  An ice skater pulling in her arms will rotate faster, and conversely, extending her arms will slow her rotation.  If her arms are extended to the radius of the planet, her rate of spin will slow to unnoticeable (to us), seeming instead to go in a […]

After remembering my dreams in the bath the other morning, I puzzled some more about gravity, wondering “where is the equal and opposite reaction to the force of gravity?” Looking at gravity from Einstein’s point of view, that it is a curving of spacetime, allowed me to wonder if there shouldn’t be a corresponding negative […]