Magnetic Field Twists Scorching Matter express
A juggler tosses clubs while sitting on a spinning chair. If he starts spinning the clubs all in one direction, the chair will rotate the opposite way — otherwise, the conservation of angular momentum would be violated. That's roughly how the Einstein–de Haas effect works: in a piece of iron, a magnetic field aligns microscopic spin magnets, and the whole piece turns slightly.
Physicists have now carried this idea into the world of quark-gluon plasma — the scorching matter that is born for a fleeting instant in heavy-ion collisions. Even a residual magnetic field, after the initial flash has died down, can align particle spins. And the compensation for this alignment makes the entire fireball rotate. The resulting rotation speed is comparable to what is measured from the polarization of escaping hyperons.
Previously, it was thought that the swirl arises only from off-center nuclear impacts, like water swirling into a vortex when you stir it with a spoon. Now it turns out that hot nuclear matter can spin itself up without any initial kick. It becomes a self-spinning magnetic fluid — a state in which quantum spins and collective motion are intertwined in a single dance. Such a mechanism could have operated in the early Universe, where magnetic fields and hot plasma also coexisted.
The Einstein–de Haas effect was discovered in 1915: Einstein and de Haas suspended an iron cylinder from a thread and switched on a magnetic field — the cylinder indeed rotated, confirming the link between spin and rotation.
In Robert Wilson's novel 'Spin', characters control the rotation of entire planets by manipulating particle spins — vaguely reminiscent of the idea of self-spinning matter.