What makes someone a "morning lark" or a "night owl?" Why does jet lag hit us so hard, and why do some people struggle each ...

Scientists have discovered something remarkable about our planet: the familiar cycle of spring, summer, autumn, and winter—the seasons we take for granted—is not as uniform as we once thought. Using ...

Officials said the error is likely too minute for the general public to clock it, but it could affect applications such as critical infrastructure, telecommunications and GPS signals.