The rate at which the Earth spin, changed in an unusual way on June 29, 2022. However, you may be excused for not even noticing because it probably had such a negligible effect on your life.
You did, in fact, extend your day by 1.59 milliseconds, as absurd as it may sound.
Yet why? Our planet reportedly set a new record for the shortest time to complete one rotation on that day, according to TimeAndDate.com.
A day is defined as the 86,400 seconds, or 24 hours, that it takes for the Earth to complete one rotation. The Earth does not, however, rotate precisely evenly. The length of the day really lengthens by an average of 1.8 milliseconds every century as the Earth’s rotation slows down. This indicates that there were only 21 hours in a day 600 million years ago.
The crux of the situation.
About 4.5 billion years ago, a dense cloud of interstellar dust and gas collapsed in on itself and started spinning, giving rise to our solar system. Due to angular momentum, our planet’s ongoing rotation contains remnants of this initial movement.
Our earth has been rotating for billions of years and we have the experience of day and night because of its angular momentum. However, it hasn’t always rotated at the same speed.
In the time it took for Earth to orbit the Sun hundreds of millions of years ago, Earth performed roughly 420 revolutions; by looking at the growth lines on ancient corals, we can see proof that each year was packed with extra days.
Days have gotten longer over time (partly due to how the moon pulls on Earth’s seas, which slows us down a little), but under humanity’s watch, we have remained constant at around 24 hours for a full rotation, which translates to about 365 revolutions every journey ’round the Sun.
Scientists have discovered that there aren’t many fluctuations in how long it takes for the Earth to complete a full rotation as they’ve gotten better at measuring its rotation and keeping track of time.
The International Earth Rotation and Reference Systems Service monitor the speed of the planet’s rotation using a variety of methods, including sending laser beams to satellites to detect their movement. At exactly 11:59:59 pm on June 30 or December 31, scientists from across the world coordinate to halt atomic clocks for exactly one second to allow astronomical clocks to catch up when the time plotted by Earth’s movement approaches one second out of sync with the time measured by atomic clocks. There it is—a leap second.
Leap seconds function somewhat similarly to the leap days that are added to February at the end of every fourth year to account for the fact that the Earth actually orbits the Sun in 365.25 days. However, leap seconds are unexpected, as opposed to leap years, which occur consistently every four years.
Reasons and consequences
The tidal effects of the Moon and Sun, core-mantle coupling within the Earth, and the overall distribution of mass on the globe are some of the causes of the fluctuation in day duration. The length of the day can also be impacted by glaciation, weather, ocean currents, and the Earth’s magnetic field. Scientists are still unsure exactly what is accelerating Earth’s rotation, but some have hypothesized that it may be caused by glaciers melting during the 20th century or reservoirs filling up with a lot of water in the northern hemisphere. However, specialists believe that this acceleration is only a transitory phenomenon and that the Earth will eventually begin to slow down once more.
There is currently a worry that if Earth’s rotation speed continues to rise, we may need to have a negative leap second. In other words, to put the atomic timescale back into alignment with Earth, we must subtract a second from it rather than adding one to allow Earth to catch up.
Scientists would face a completely new set of difficulties in the event of a negative leap second. A negative leap second has never occurred before, and it’s a concern because the necessary software has never been operationally tested.
These minute adjustments, whether positive or negative, can pose major problems for sectors like telecommunications and navigation systems because leap seconds tamper with time in a way that computers aren’t designed to handle.
The fact that time is continuous serves as the internet’s main support system. Things break down when there is not a constant flow of information. Repeating or skipping a second might throw off the entire system and result in gaps in what should be a continuous stream of data. Leap seconds can pose a hurdle to the banking sector because each transaction needs a distinct time stamp, which can become problematic if the time interval of 23:59:59 repeats.
Some businesses have looked for their own approaches to jump seconds. On a day with a leap second, Google extends each second by a fraction of a second rather than stopping the clock to allow Earth to catch up with atomic time. But that isn’t consistent with the way time is defined internationally.
