The data coming out of USC neatly explains why a few milliseconds of extra sunlight have been seen, over a six year cycle repeatedly on Earth, since at least the time that Nixon was in office. Here's the whole story -- and a bit:
. . .Believed to consist mostly of an iron-nickel alloy, the inner core is mainly a solid ball with a radius of about 760 miles (1,220 km). It rotates slightly faster than the planet as a whole (from time to time, only now), which is called "super-rotation". . . .
University of Southern California (USC) scientists have found evidence that the Earth’s inner core oscillates, contradicting previously accepted models that suggested it consistently rotates at a faster rate than the planet’s surface.
Their study, published today (June 10, 2022) in the journal Science Advances, shows that the inner core changed direction in the six-year period from 1969-74, according to the analysis of seismic data. The scientists say their model of inner core movement also explains the variation in the length of a day, which has been shown to oscillate persistently for the past several decades. . . .
I'd be willing to bet that this oscillating inner core dynamic is a common feature of rocky worlds in this size class, and may help preserve both the atmosphere and the magnetic field, of such worlds. . . kind of like a gyroscope's action -- but on a planetary scale. We already know that there is a region under Africa where anomalies in the magnetic properties of the planet exist. . . like a void in a layer cake.
Perhaps this oscillation helps ameliorate that effect, to keep planets from. . . dying, like Barsoom did some 3 billion years ago. Who knows? But some future mission to Mars may confirm or refute this idea. It is fascinating that the USC data stems from another earlier oscillation period (1979-to-1984), then in. . . the Big Easy. Onward, grinning. . . .
नमस्ते
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