Time is one thing that is seen as a constant. There are always 24 hours in a day, give or take a few fractions of a second. Despite seeing time as a constant, the length of days does vary slightly. That is is the reason we have a leap year every four years. Scientists recently announced something very interesting. Days have started to be shorter on average because the Earth is spinning faster.
The faster spin of the planet could require adjustments to keep calendars on track. Scientists do point out that the faster spin doesn’t put the planet in danger of any sort. The reason for the increased spin is very well understood, and things that impact it include lunar gravity, snowfall levels, and mountain erosion. Over the last several decades, the precision of atomic clocks allowed scientists to make more accurate adjustments to the measurement of time.
Leap seconds have been added in the past to keep clocks in proper timing outside of leap year. Interestingly, since scientists began measuring time with high accuracy, the length of days has been trending to be slightly longer by a fraction of a millisecond. That trend has now reversed.
Researchers point out July 19 as being a notably shorter day at 1.4602 milliseconds below the standard. Before July 19, the previous record for the shortest day was set in 2005, but in 2020 that record was exceeded 28 times.
With the rotation of the earth speeding up, researchers say that we may need to add a negative leap second in the next few years to keep clocks synchronized. That would be the first negative leap second added. Some scientists believe that the increased rotation of the earth could be a result of global warming.