From ABC News (28/3/24)…
Global warming may be slowing Earth’s spin and affecting how we keep time
Melting polar ice caps are a sad sign of our times, but they may have given global timekeepers an unexpected reprieve, according to new research.
For decades, experts have been trying to reconcile the precise time, as set by atomic clocks, with the somewhat unreliable speed at which the Earth spins.
Since 1972, authorities have added 27 leap seconds to our time standard – UTC, or Co-ordinated Universal Time – to compensate for a slow-down in the Earth’s spincaused largely by the pull of the Moon on the oceans known as “tidal friction”.
Keeping UTC in step with the Earth’s rotation means, among other things, that we can expect the Sun to come up at a particular time in the morning, and astronomers can easily work out when to point their telescopes at a particular part of the sky.
But the addition of leap seconds happens at irregular intervals, with just six months’ notice, causing a headache for global technology systems – from power grids to financial markets, and from satellites to social media networks.
