Earth spinning faster and recording its shortest-day ever is no reason to panic, scientists say
While the Earth on June 29 did indeed record its shortest day since the adoption of the atomic clock standard in 1970 — at 1.59 milliseconds less than 24 hours — scientists say this is a normal fluctuation.
Still, news of the faster rotation led to misleading posts on social media about the significance of the measurement, leading some to express concern about its implications.
"They broke news of earth spinning faster which seems like it should be bigger news," claimed one tweet that was shared nearly 35,000 times. "We so desensitized to catastrophe at this point it's like well what's next."
Some Twitter users responded to these tweets with jokes, as well as skepticism about the magnitude of the measurement. Others, however, voiced worries about how it would affect them.
But scientists told the AP that the Earth's rotational speed fluctuates constantly and that the record-setting measurement is nothing to panic over.
"It's a completely normal thing," said Stephen Merkowitz, a scientist and project manager at NASA's Goddard Space Flight Center. "There's nothing magical or special about this. It's not such an extreme data point that all the scientists are going to wake up and go, what's going on?"
Andrew Ingersoll, an emeritus professor of planetary science at the California Institute of Technology, agreed with this assessment.
"The Earth's rotation varies by milliseconds for many reasons," he wrote in an email to the AP. "None of them are cause for concern."
The slight increase in rotational speed also does not mean that days are going by noticeably faster. Merkowitz explained that standardized time was once determined by how long it takes the Earth to rotate once on its axis — widely understood to be 24 hours. But because that speed fluctuates slightly, that number can vary by milliseconds.
Scientists in the 1960s began working with atomic clocks to measure time more accurately. The official length of a day, scientifically speaking, now compares the speed of one full rotation of the Earth to time taken by atomic clocks, Merkowitz said. If those measurements get too out of sync, the International Earth Rotation and Reference Systems Service, an organization that maintains global time, may fix the discrepancy by adding a leap second.
Some engineers oppose the introduction of a leap second, as it could lead to large-scale and devastating tech issues. Meta engineers Oleg Obleukhov and Ahmad Byagowi wrote a blog post about it for Meta, which is supporting an industry-wide effort to stop future introductions of leap seconds.
"Negative leap second handling is supported for a long time and companies like Meta often run simulations of this event," they told CBS News. "However, it has never been verified on a large scale and will likely lead to unpredictable and devastating outages across the world."
Despite recent decreases in the length of a day over the last few years, days have actually been getting longer over the course of several centuries, according to Judah Levine, a physicist in the Time and Frequency Division of the National Institute of Standards and Technology. He added that the current trend was not predicted, but agreed it's nothing to worry about.
Many variables impact the Earth's rotation, such as influences from other planets or the moon, as well as how Earth's mass redistributes itself. For example, ice sheets melting or weather events that create a denser atmosphere, according to Merkowitz.
But the kind of event that would move enough mass to affect the Earth's rotation in a way that is perceptible to humans would be something dire like the planet being hit by a giant meteor, Merkowitz said.
Caitlin O'Kane contributed to this report.