28/03/2024
'WE'RE IN A VERY UNUSUAL TIME'
Earth’s changing spin is threatening to toy with our sense of time, clocks and computerized society in an unprecedented way — but only for a second.
“This is an unprecedented situation and a big deal,” said study lead author Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography at the University of California, San Diego.
“It’s not a huge change in the Earth’s rotation that’s going to lead to some catastrophe or anything, but it is something notable. It’s yet another indication that we’re in a very unusual time.”
Ice melting at both of Earth’s poles has been counteracting the planet’s burst of speed and is likely to have delayed this global second of reckoning by about three years, Agnew said.
“We are headed toward a negative leap second,” said Dennis McCarthy, retired director of time for the U.S. Naval Observatory who wasn’t part of the study. “It’s a matter of when.”
Earth’s speeding up because its hot liquid core — “a large ball of molten fluid” — acts in unpredictable ways, with eddies and flows that vary, Agnew said.
Agnew said the core has been triggering a speedup for about 50 years, but rapid melting of ice at the poles since 1990 masked that effect. Melting ice shifts Earth’s mass from the poles to the bulging center, which slows the rotation much like a spinning ice skater slows when extending their arms out to their sides, he said.
Without the effect of melting ice, Earth would need that negative leap second in 2026 instead of 2029, Agnew calculated. | via Associated Press
