Two Spinning Tales and Time

Earth’s inner core stopped spinning. But don’t fret, it appears this happens from time to time, say every seven decades or so.
A new study published in Nature Geoscience by geophysicists Yi Yang and Xiadong Song of Peking University in Beijing explored the nature of movement of Earth’s inner core, largely made up of iron and molten liquids. They found the inner core’s movement recently reduced enough they consider it “paused,” all part of what “seems to be associated with a gradual turning back of the inner core as a part of an approximately seven-decade oscillation.”
The last turning point was in the early 1970s.
Uh, Earth’s Inner Core Just Stopped Spinning 

It may seem fantastical to say there is a planet within Earth, but conceptually it is true. Ever since the 1990s, geophysicists have known that Earth's inner core— a ball of iron with a radius of 746 miles (more than two-thirds the size of the moon) — spins in the center of our planet at a different pace than the rest of the globe. In a sense, this separation makes the inner core a bit like a planet of its own.
Earth's inner core is slowing down — and the length of a day may change as a result