Since Newton realized that bodies attract via gravity, the motion of three objects has been a puzzle. Poincaré proved that such a system is dominated by chaos. However, islands of order have been found — cycler orbits, allowing a body to take turns circling two stars. Previously they were thought unstable: the slightest nudge would ruin the trajectory. New numerical simulations show: if the stars have different masses (analyzing pairs up to a Sun-Jupiter mass ratio), orbits protected from perturbations arise. The route resembles a cable car between two peaks: the car glides along the wire without falling, even when swaying.

Stability comes from regions around the orbit where motion remains regular under small nudges. A planet on such a path can wander between the stars for billions of years without risking a fall into a star or ejection into interstellar space. Astonishingly, some cyclers even survive partial mass loss from a star — for example, when it becomes a red giant.

This discovery transforms the search for exoplanets in double-sun systems. Nomad worlds might have been born inside protoplanetary disks — clouds of gas and dust around young stars. This links dynamics with star formation and the evolution of the interstellar medium. Planetary migration turns out not to be chaotic wandering but motion along invisible rails.