علماء يعتقدون أن لب الأرض قد يكون عكس دورانه
January 27, 2023 - قال علماء في جامعة بكين في في العاصمة الصينية إن لب الأرض ربما يكون قد بدأ في الدوران في الاتجاه المعاكس
In 1936, Danish seismologist Inge Lehmann announced his discovery that a liquid outer core envelops a solid metal marble at the centre of our planet — a finding which has bamboozled scientists ever since.
Scientists say Earth consists of three main parts – the crust (the planet’s surface that we live on), the mantle and the core.
The core can be sub-divided into an outer core and an inner core. The latter is as hot as the sun, and because it is under so much pressure, is a solid ball of iron and nickel.
Since the inner core floats in a sea of liquid iron and nickel (outer core) it is free to spin independently and not necessarily in sync with the rest of the planet’s rotation.
Scientists from Peking University in China have been studying the way seismic waves from earthquakes travel through the planet, and believe they have discovered that the Earth’s inner core rotation has paused and that over the years it has been swirling from one direction to another in a cycle approximately 70 years long.
Not all scientists agree with the new findings, however.
Dr John Vidale, a Geophysicist from Southern California who wrote a paper last year citing much faster changes in the core’s spin direction, says, “Our image of the inner Earth is still blurry. Something’s happening and I think we’re going to figure it out, but it may take a decade”.
Changes within the Earth’s core have an impact on humans by altering things like navigation and even the length of the day, although only by milliseconds.
- Making heads spin: Scientists say Earth’s inner core has changed its rotation (Euronews)
- Earth’s inner core: A shifting, spinning mystery’s latest twist (New York Times)
- Earth’s inner core may have started to spin in opposite direction (BBC)
- Has Earth’s inner core stopped its strange spin? (Nature Geoscience)
- Full report (Nature Geoscience)