The length of a day isn’t always exactly 24 hours, and now scientists warn that the shortest day ever recorded is coming soon. Earth’s rotation is speeding up, causing our days to shrink by small but measurable amounts.
Normally, Earth spins about 365 times per year, which defines our calendar. However, over time, this number has changed due to factors like shifting seas, movements within Earth’s core, and the Moon moving farther away.
Currently, Earth is spinning faster than usual, and no one knows why. Astrophysicist Graham Jones from the University of London says the acceleration could occur on July 9, July 22, or August 5, shortening the day by up to 1.51 milliseconds.
While these tiny changes might seem insignificant, they can disrupt GPS technology and the way we keep time. Leonid Zotov of Moscow State University explains that scientists didn’t expect this acceleration and that it can’t be explained by ocean or weather patterns. The cause might be something happening inside Earth.
Earthquakes can also affect rotation speed. The 2011 earthquake in Japan, for instance, shifted Earth’s axis and made days shorter. NASA’s Dr. Richard Gross compared this to a skater pulling in their arms to spin faster, as the quake moved Earth’s mass closer to its rotation axis.
Though Earth is spinning faster now, researchers say it will eventually slow down again, but the timing remains uncertain.
