Check out this resource to learn more about the Atomic Clock of the United States. The atomic clock is closely synchronized to UTC. UTC is the successor to Greenwich Mean Time. You can see how closely your own clocks are running based on the atomic clock. For those not in the United States, don't worry, the clock automatically adjusts to whatever timezone your computer is set.

To further explore this topic, it might be helpful to understand gravity and centripetal force.

This site looks at the equation used to calculate centripetal force. It even provides a tool to calculate the force based on values entered.