July 9, 2025 may be shortest day on Earth. Here’s why. | News

It’s a phenomenon that has left scientists baffled, but the Earth’s rotation is spinning unusually fast and Wednesday may be the shortest day ever on record.

The shortest day of the year could fall Wednesday or July 22 or August 5, days when the moon is farthest from the equator. 

Now the idea that days could become shorter or longer sounds like the plot of science fiction book, but most people will probably not even notice the difference. Scientists with the International Earth Rotation and Reference Systems Service measure differences in the length of day by milliseconds. 

According to Time and Date, a website that tracks time and time zones, the current record holder for the shortest day on record was July 5, 2024, which was 1.66 milliseconds shorter than 24 hours. Each year since 2020 has seen a new shortest day on record. 

Earth spins faster when the Moon’s orbit is significantly north or south relative to the equator. 

Scientists expect Wednesday to be between 1.3 and 1.6 milliseconds shorter than 24 hours, The New York Post reports. 

While events such as large earthquakes have been known to impact the earth’s speed, scientists have been unsure about the cause of the acceleration they are seeing, according to the BBC.  

Leonid Zotov, an expert on Earth rotation from the Moscow Institute of Electronics and Mathematics, told Time and Date that most scientists believe the cause must be from inside the Earth as ocean and atmospheric models do not account for the leap in speed.