AUSTIN (KXAN) -A bit of news you didn’t expect, in a new study published this week in Nature Geoscience, scientists announced that they believe the Earth’s inner core has stopped spinning.
Scientists Yi Yang and Xiaodong Song from Peking University published the paper. They observed changes in the length of the Earth’s day and magnetic field, which they said implied changes in the core.
Based on seismic observations from 1964 through today, the pair said in their paper that they believe that the inner core goes through “an approximately seven-decade oscillation.” Basically, the inner core slows and then spins in the opposite direction every seventy years.
Song helped discover that the core spins in a study published in 1996, by studying seismic waves created by earthquakes.
The core is stopping! Are we all in danger?
According to the research, this slowing and reversing is a natural part of the core’s cycle.
The core, according to the researchers, likely “paused” its spin in the last decade. It may now be turning back the opposite direction it was spinning before. The core slowed the most in 2009, according to the research.
The slowing and reverse spin could help explain changes in sea level and the length of days every 70 or so years, according to the researchers.
“Interestingly, the same multidecadal periodicity is also well observed in the Earth’s climate system, especially the global mean temperature and sea level rise,” the team said in their paper.
Why does the Earth’s core spin?
According to the research, differences between the mantle, outer and inner core cause the core to spin.
The inner core is about 70% of the moon’s radius and is believed to be primarily made of iron. It is believed to be solid.
The outer core is liquid. It is made of iron and nickel and is very hot. The temperature of the core is believed to be 9,800 degrees Fahrenheit.
We know a little more about the Earth’s mantle. It makes up 84% of the Earth’s volume. It is primarily solid but acts sort of like caramel, according to NASA.
The paper states that as the outer core cools, it fuses with the inner core. During this transition, heat is released, generating the Earth’s magnetic field. This, plus the gravity exhibited by the mantle, causes the inner core to spin.
The existence of the core itself was discovered in 1936 by Danish seismologist Inge Lehmann. She discovered the core in New Zealand after noticing that seismic waves appeared to reflect off of something solid. In 1940, the core was first hypothesized to be made of iron.