Double stars lose speed like a figure skater who slows their spin by extending their arms. In a close pair, one star transfers mass onto a white dwarf. The magnetic field of the donor star, consisting mostly of hydrogen, entangles the outflowing gas and flings it away, as if the skater's arms were pulling the spin outward. This magnetic braking reduces the system's orbital period. Previously, it was thought that when a star becomes fully convective (its interior churns like a boiling liquid), braking almost disappears. But analysis using spectroscopy showed: the weakening is only 2–3 times. That's enough to explain the observed periods of binary systems and the sizes of donor stars. Surprisingly, even with full convection, the magnetic field doesn't switch off — the skater slows down smoothly, not abruptly. This picture refines the evolution of stellar pairs and the nature of the magnetic dynamo, which also operates in our Sun, which once spun many times faster.