We just experienced Earth’s shortest day since the 1960s. June 29, 2022 came to an end 1.59 milliseconds sooner than expected. At first glance, such a small amount of time difference might not seem like a big deal. However, some warn that it could have catastrophic effects if we keep introducing leap seconds to account for the changes in the Earth’s rotational speed.
We experienced Earth’s shortest day in 50 years last month
Experiencing Earth’s shortest day isn’t a big deal in and of itself. After all, in 2020 alone, the planet experienced 28 of its shortest days in the past 50 years. Scientists first began measuring the Earth’s rotation using high-precision atomic clocks in the 1960s. Since then, we’ve seen a number of changes to the way time works on our planet.
While we’ve seen some shorter days, by most accounts, the Earth’s rotation is actually slowing down. Scientists say the Earth used to complete a rotation in less than 19 hours around 1.4 billion years ago. Over the centuries, though, the average length of a day has changed. To account for these differences, the Telecommunication Union, a body with the United Nations, has started adding occasional leap seconds in June or December.
The most recent leap second was added in 2016. To account for these leap seconds, astronomers essentially stop the clocks for a second so Earth can catch up. The first leap second was added back in 1972, with 26 more being added throughout the last several decades. If a new leap second were added this year, though, it could be the first negative leap second. And that has raised some concerns.
It could lead to catastrophic effects, Meta says
The notion of leap seconds was invented to help combat the slowdown of the Earth’s rotation. However, with this latest of Earth’s shortest days having us looking at a negative leap second, Meta is concerned we could be seriously impacting systems that rely on timers and clocks. That’s because IT industries now rely on International Atomic Time (TAI) or Universal Time (UT1) for timing.
In 1972, when the leap second was introduced to help keep UTC in check, many institutions used it heavily. However, UTC has become “bad” for the telecom industry. As a result, many applications rely on TAI or UT1, as noted above. Meta wants to stop future introductions of leap seconds as the company believes it does more harm than good.
But every leap second added is a “major source of pain for people who manage hardware infrastructures,” Meta says. Additionally, “smearing” a leap second by slowing down or speeding up the clock isn’t universal. This means it could lead to additional issues as well. So, while we may be experiencing some of Earth’s shortest days, the leap second may not be a viable solution in the future.