Soon, the length of a second could change

                For nearly 50 years, the length of a second has been defined in the same way. But researchers in Germany have found how to make the most accurate clock ever created, which if it had started 14 billion years ago at the Big Bang would have lost just 100 seconds.

                While the change in accuracy would hardly be noticed by human, it could be significant for GPS navigation as well as electrical power grids. And because the clock uses a different way of measuring time, it could alter length of seconds, minutes and hours by miniscule amount.

                Time is measured based on the idea of a pendulum. Since 1967, the International System of Units has defined second as the time that elapses during 9,192,631,770 cycles of the microwave signal produced by these oscillations. However, they have an error of about a nano-second every 30 days.

                A paper in journal Optical says the new clock uses strontium atoms, which “tick” much faster than the microwave, part of the spectrum. If a second was defined in terms of strontium, the equivalent SI unit would be 429,000 billion cycles. This method of calculating length of a second reduces the error to less than 0.2 nanoseconds in 25 days.