Mysteriously, ocean and atmospheric waves near the equator all share the property that they travel eastwards. Now, Pierre Delplace of the University of Lyon and colleagues have suggested a topological origin to this effect, with time-reversal symmetry broken by Earth’s rotation. Remarkably, the work points to a formal analogy between equatorially trapped waves and topological insulators, showing yet another example of the unity of physics.

Further reading
P Delplace et al. 2017 Science 358 1075.