Earth’s core has ‘reversed’ rotation. What does that mean for us?

The article discusses the recent discovery that the Earth's core has "reversed" its rotation, slowing down and even stopping its movement relative to the Earth's crust. This phenomenon has been observed by scientists since 2024, though it has not yet had a significant impact on the general public. The Earth's core is composed of a liquid outer layer and a solid inner layer, both made primarily of iron and nickel. Traditionally, it was assumed that the inner core rotated at a constant rate, but seismic analyses have revealed that this rotation can fluctuate significantly, with the core sometimes moving faster or slower than the Earth's crust. These changes in rotational speed can slightly affect the length of a day, by a matter of milliseconds, which could impact astronomical measurements and satellite operations. Potential changes to the Earth's magnetic field and climate are also possible, though the full implications are not yet clear. The article emphasizes that the core does not actually rotate in the opposite direction, but rather appears to do so because its rotation has slowed relative to the Earth's crust. This cycle of fluctuation is estimated to occur every 70 years.