Earth’s inner core (shown in bright yellow and white in this illustration) may have stopped rotating
earthly the inner core may have stopped rotating – and could potentially rotate in the opposite direction, according to the latest surprising scientific news.
What does it all mean?
Well, the Earth has an inner core consisting mostly of solid iron. It is about 70% of the width of the Moon and is separated from the rest of the Earth by a liquid outer core.
This outer core has a magnetic field that affects the rotation of the inner layer, while the higher level gravitational pull known as the mantle also affects the rotation of the core.
This new study, published Tuesday in the journal Nature Geoscience and conducted by scientists Yi Yang and Xiaodong Song of China’s Peking University, suggests that the inner core may have stopped rotating over the past decade.
Song and Yang told Vice that there are two main forces acting on the inner core – the electromagnetic force and the other is gravity.
There is a “pull and pull” element between these two forces.
“We see strong evidence that the inner core is rotating faster than the surface [but] around 2009, it almost stopped,” said Yang and Song.
“Now it is gradually moving[ing] in opposite direction.”
Should we be worried?
It sounds like a big deal, but actually the Earth is pretty chaotic beneath the surface, so it’s not as worrisome as you might think.
The researchers came to this conclusion by analyzing data on seismic waves emitted by earthquakes that have managed to penetrate the Earth’s inner core over the last 60 years for their study.
Indeed, the fact that the inner core regularly changed direction first appeared in the 1990s, although researchers have been divided over the exact speed of rotation ever since.
In fact, Yang and Song believe from their research that it may be “experiencing a comeback in a multi-decade oscillation, with another turning point in the early 1970s.”
Scientists have suggested that this “oscillation” cycle is likely to last seven decades, so the inner core spends 35 years in one direction and 35 years in the other.
However, not everyone agrees with these findings.
Geophysicists John Vidale of the University of Southern California were not involved in the study, but said the most credible conclusion from this new study is that “the last 10-year period has less activity than before.”
Do these findings matter?
Well, it can help scientists understand how what happens deep below the Earth’s surface affects life in the Earth’s crust – where we live – such as the length of each day.
Song described the inner core as “a planet within a planet, so how it moves is obviously very important” – although the exact workings of the core are still unknown.
It’s still unclear how fast the inner core spins and if it changes.
Vidale told The New York Times: “It’s most likely not relevant to life on the surface, but we don’t really know what’s going on. It’s our responsibility to figure it out.”