There are days when time seems to run faster, even though this is imperceptible to human beings, who are used to counting them every 24 hours. But this has actually happened recently: June 29 was recorded as the shortest day since the 1960s, when scientists began measuring the planet’s rotation with UTC (Coordinated Universal Time), with the Earth rotating 1.59 milliseconds faster than usual.
This phenomenon of shorter days has been occurring more frequently in recent times, according to the British newspaper The Guardian. Nearly a month later, on July 26, that record was nearly broken, as the Earth spun 1.5 milliseconds faster.
In 2020, there were 28 records of the fastest days in the last 50 years, with a record on July 19, when the planet was 1.46 milliseconds faster – a mark beaten now in June.
NASA believes that the strongest winds in El Niño years can slow the planet’s rotation, extending the day by a fraction of a millisecond.
On the other hand, earthquakes have the opposite effect, like the one in 2004 that triggered a tsunami in the Indian Ocean, shifting rocks and shortening the length of the day by nearly 3 microseconds.
To contain damage over time differences, the International Telecommunication Union added occasional leap seconds in June or December in 2016, stopping clocks by a second to synchronize with Earth time. The first leap second was added in 1972.
If the trend of shorter days continues over the long term, this could lead to the first second short of history: instead of adding a second to clocks, time would skip a second to keep up with the planet.