NIGHT and day are at the mercy of Earth’s twisted heart. Fluctuations at the core subtly shift the planet’s rotation over a six-year cycle.
Nicolas Gillet of the University of Joseph Fourier in Grenoble, France, and colleagues, modelled fluid behaviour in the Earth’s core based on measurements of fluctuations in the magnetic field.
The innermost region of the Earth’s outer core periodically flows faster or slower, and this action “tugs” at the planet’s magnetic field, says Gillet. Like an array of rubber bands, the field then pulls the region back towards its original position. But the effect ripples outward,…
