The Earth is having shorter days

Our planet has been spinning a little faster than usual and this trend is expected to continue into early August. On July 9, it’s estimated that the day was about 1.3 to 1.6 milliseconds shorter, based on the planet’s rotation. According to an article on space.com, July 22 and Aug. 5 should also have shorter days. One of the shortest days in recent history happened June 29, 2022, when the Earth completed its full one-day rotation in 1.59 milliseconds less than 24 hours.

The Earth’s spin does fluctuate on a day-to-day basis primarily due to gravitational forces from the moon. Based on data from atomic clocks, our length of day has increased by an average of 1.7 milliseconds compared to a century ago. Historical astronomical records show that the Earth’s length of day has also increased by about 2.3 milliseconds since the eighth century.

This recent measurement shows that the Earth had its shortest day since the invention of atomic clocks. According to Wikipedia, these highly sensitive clocks measure time by “monitoring the frequency of radiation of atoms.” They are currently used for navigation with satellite networks and GPS systems.

These devices were first proposed as early as 1873 by Scottish physicist James Clerk Maxwell. The first accurate atomic clock was put together in the mid-1950s. In 1967, the atomic clock was used to redefine the standard units of time based on atomic frequencies.

The Earth’s rotation is not constant and can vary slightly as the friction of moon will help to slow it down on occasion. Back on July 9, the moon was farthest from the Earth in its orbit and created a gravitational pull. This is believed to have slightly altered the planet’s wobble, which led to a slight increase in the Earth’s speed of rotation.

Scientists estimate that the age of our planet is about 4.5 billion years. They have also determined that a full day was around 18 hours and 40 minutes, approximately 1.4 billion years ago, according to an article from The Guardian. Based on the data, the Earth’s spin has been slowing down. Occasionally, we have been adding leap seconds to compensate, as the last adjustment was Dec. 31, 2016.

The overall purpose of leap seconds is to keep Coordinated Universal Time within 0.9 seconds of Earth’s rotational time.

The leap second began in 1972, but there has been increasing pressure to eliminate them due to computer and satellite technologies. The aviation industry relies on accurate timekeeping for flight scheduling. According to an article in LiveScience.com, there have been about 10 lead seconds added, plus over several dozen additions when the time systems drifted by more than 0.9 seconds. However, in 2022, it was voted by an international group of experts that the lead second will be abolished by 2035.

It's estimated that our planet’s rotation will pick up one second each century as it slows down. In about 5,000 years, a full day will be 23 hours rather than 24 hours.

In terms of our local weather, the strong ridge of high pressure continues to dominate much of the western U.S. There are some showers expected early this week, but as of the weekend, no measurable rainfall has been reported at Cliff’s station in Coeur d’Alene since June 23. Based on his records that go back to 1895, it has never been this dry from late June into the middle of July.

As I mentioned last week, the long-range computer models are continuing to show the big ridge holding on across the western U.S. into at least early August. However, there is still a chance of a few isolated showers or a thunderstorm as a few storm systems move southward out of Canada, but most of the activity would be over the mountains.

As of the weekend, there have been 11 days with high temperatures at or above 90 degrees in Coeur d’Alene. As we get toward the end of July, there are indications of another heatwave across the Inland Northwest with more 90-degree temperatures expected. It’s also possible that we could challenge the 100-degree mark.

With a dry and hotter-than-normal first part of the summer season, it’s possible that the second portion of summer may not be as hot or as dry. Eventually, weather patterns in this part of the country will flip to the other side. There have been many occasions when we go from drought to floods.

Based on the current pattern, it’s difficult to say at this time how much moisture we’ll receive in the late summer and fall. There is currently a “La Nada,” the in-between warmer El Niño and cooler La Niña event in the waters of the south-central Pacific Ocean. This La Nada pattern is forecast to remain intact for at least the next three months. But, there are a few computer models that are pointing to the possible formation of a weak La Niña at the end of the year. Our region typically receives more moisture from a La Niña event during the winter season. Stay tuned.

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Contact Randy Mann at [email protected].