We may have finally figured out how galaxy-scale magnetic fields arose

We may finally know how the magnetic fields that now permeate the universe first arose. Much of the universe was once a churning unmagnetised plasma, and a new set of simulations shows how that plasma may have developed powerful magnetic fields.

Lorenzo Sironi at Columbia University in New York and his colleagues simulated turbulence in plasma to study a phenomenon called the Weibel instability. When a fluid is turbulent, asymmetries can develop when more particles happen to be moving in one direction than the …