A ‘leap second’ was added to the Indian clock at 5:29.59 hours on the first day of 2017 to synchronise with the Earth’s rotational clock. As the atomic clock at the National Physical Laboratory (NPL) struck 23:59:59 last night as per the Indian Standard Time (IST), it was programmed to add an extra second to 2017 to compensate for a slowdown in the Earth’s rotation.
Adding a second barely has an impact on the daily life, but it does matter in the fields of satellite navigation,astronomy and communication. “The Earth and rotation around its own axis is not regular, as sometimes it speeds up and sometimes it slows down due to various factors, including earthquakes and moon’s gravitational forces. As a result, astronomical time (UT1) gradually falls out of sync with atomic time (UTC), and, as and when the difference between UTC and UT1 approaches 0.9 seconds, a leap second is added to UTC through atomic clocks worldwide,” D. K. Aswal, Director of NPL, said.
Atomic clocks are so precise that the margin of error in its functioning is just of a second in 100 million years. “The leap second adjustment is not so relevant for normal everyday life. However, this shift is critical for applications requiring time accuracies in the nanosecond, which are critical in the fields of astronomy, satellite navigation, communication networks,” Mr. Aswal added.
Adding the leap second to the Indian clock is done by the NPL under the Council for Scientific and Industrial Research. The NPL, one of the oldest laboratories in the country, has five atomic clocks and nearly 300 such pieces exist across the globe.