NYT SCIENCE: Earth’s Inner Core: A Shifting, Spinning Mystery’s Latest Twist
By Robin George Andrews
Section: Science
Source: New York Times
Published Date: January 23, 2023 at 02:00AM
That core may be on the cusp of a big shift. Seismologists reported Monday in the journal Nature Geoscience that after brief but peculiar pauses, the inner core changes how it spins — relative to the motion of Earth’s surface — perhaps once every few decades. And, right now, one such reversal may be underway.
This may sound like a setup for a world-wrecking, blockbuster movie. But fret not: Precisely nothing apocalyptic will result from this planetary spin cycle, which may have been happening for eons. The researchers who propose this speculative model instead aim to advance understanding of Earth’s innermost sanctum and its relationship with the rest of the world.
The inner core is like “a planet within a planet, so how it moves is obviously very important,” said Xiaodong Song, a seismologist at Peking University in Beijing and an author of the study.
In 1936, the Danish seismologist Inge Lehmann discovered that Earth’s liquid outer core envelops a solid metal marble — and it has bamboozled scientists ever since.
“It’s weird that there’s a solid iron ball kind of floating in the middle of the Earth,” said John Vidale, a seismologist at the University of Southern California who was not involved with the study. Scientists think the core crystallized out of a molten metal soup at some point in Earth’s not-too-distant past, after the planet’s internal inferno had sufficiently cooled.
The inner core cannot be directly sampled, but energetic seismic waves emanating from potent earthquakes and Cold War-era nuclear weapon tests have ventured through the inner core, illuminating some of its properties. Scientists suspect this ball of mostly iron and nickel is 1,520 miles long and as about as hot as the sun’s surface.
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By Robin George Andrews
Section: Science
Source: New York Times
Published Date: January 23, 2023 at 02:00AM
Researchers proposed a model with a 70-year rotation cycle of our planet’s iron heart, and report that we’re in the middle of one of its big shifts.
Imagine Earth’s inner core — the dense center of our planet — as a heavy, metal ballerina. This iron-rich dancer is capable of pirouetting at ever-changing speeds.That core may be on the cusp of a big shift. Seismologists reported Monday in the journal Nature Geoscience that after brief but peculiar pauses, the inner core changes how it spins — relative to the motion of Earth’s surface — perhaps once every few decades. And, right now, one such reversal may be underway.
This may sound like a setup for a world-wrecking, blockbuster movie. But fret not: Precisely nothing apocalyptic will result from this planetary spin cycle, which may have been happening for eons. The researchers who propose this speculative model instead aim to advance understanding of Earth’s innermost sanctum and its relationship with the rest of the world.
The inner core is like “a planet within a planet, so how it moves is obviously very important,” said Xiaodong Song, a seismologist at Peking University in Beijing and an author of the study.
In 1936, the Danish seismologist Inge Lehmann discovered that Earth’s liquid outer core envelops a solid metal marble — and it has bamboozled scientists ever since.
“It’s weird that there’s a solid iron ball kind of floating in the middle of the Earth,” said John Vidale, a seismologist at the University of Southern California who was not involved with the study. Scientists think the core crystallized out of a molten metal soup at some point in Earth’s not-too-distant past, after the planet’s internal inferno had sufficiently cooled.
The inner core cannot be directly sampled, but energetic seismic waves emanating from potent earthquakes and Cold War-era nuclear weapon tests have ventured through the inner core, illuminating some of its properties. Scientists suspect this ball of mostly iron and nickel is 1,520 miles long and as about as hot as the sun’s surface.
Read More at: https://www.nytimes.com/2023/01/23/science/earth-core-reversing-spin.html
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