The key facts
- From May 20, 2027, leap seconds will no longer be added to UTC — a decision by the International Bureau of Weights and Measures.
- Since 1972, 27 seconds have been added to world time; the acceleration of Earth's rotation could for the first time have required removing a second.
- Nothing will change for ordinary people; the time discrepancy may reach an hour only after thousands of years.
Abolition of leap seconds
The International Bureau of Weights and Measures announced that from May 20, 2027, Coordinated Universal Time (UTC), by which clocks, computers, mobile communications and other systems around the world are synchronized, will no longer be adjusted.
Why the difference arose
The Earth rotates unevenly — sometimes slightly faster, sometimes slower. Precise world time is measured by atomic clocks, whose operation does not depend on the planet's rotation: they count seconds by the oscillations of atoms. Because of this, a difference gradually accumulates between the readings of atomic clocks and the time determined by the Earth's rotation. To eliminate it, one second was periodically added to world time starting in 1972 — a total of 27 seconds were added over this period.
Acceleration of Earth's rotation
In recent years, scientists have noticed an acceleration of the Earth's rotation. Because of this, in the future there could for the first time have been a need not to add, but to remove one second. Experts feared that such an adjustment could cause failures in computer systems, communications and other critical infrastructure. Therefore, it was decided to abandon such adjustments from May 20, 2027: world time will be able to gradually diverge from the time determined by the Earth's rotation.
What will change for people
Nothing will change for ordinary people — there will be no need to reset clocks or change daily routines. According to experts, the difference between the two ways of measuring time will accumulate very slowly and may reach one hour only after thousands of years.
