NewScientist (7 January 2017) reports on the activities our core of iron is engaged in:
DEEP below our planet’s surface, a molten jet of iron, nearly as hot as the surface of the sun, is picking up speed.
This stream of liquid some 420 kilometres wide has been discovered by telltale magnetic field readings 3000 kilometres below North America and Russia. It has trebled in speed since 2000, and is now circulating westwards at between 40 and 45 kilometres per year, heading from deep under Siberia towards the underside of Europe (see diagram). That is three times as fast as the typical speeds of liquid in the outer core.
No one knows yet why the jet has got faster, but the team that made the discovery thinks it is a natural phenomenon, and can help us understand the formation of Earth’s magnetic fields, which keep us safe from solar winds. “It’s a remarkable discovery,” says Phil Livermore at the University of Leeds, UK, who led the team. “We’ve known that the liquid core is moving around, but our observations haven’t been sufficient until now to see this jet.”
There’s a lot of mystery and speculation here, but this bit is natural:
Earth’s magnetic field seems to have been weakening, especially since around 1840, at about 5 per cent per century. The molten iron stream should help us predict if and when the magnetic field of the planet’s core will flip. And thanks to the satellite monitoring system, says [Xiaodong Song at the University of Illinois in Champaign], we have opened a new window to view in real time the activity of molten iron deep in Earth’s core.
We may think we have a dynamic, vibrant world – but we don’t know the half of it. If we could see electromagnetic fields without using lots of iron bits, what would we see? How does this change things?
