Self-propelled Pair of Black Holes ⚡ экспресс
Using symmetry analysis and large-scale numerical simulations of three-body interactions, it is shown that a binary system embedded in a sea of light particles experiences more complex secular dynamics than previously thought. The discovered effects include a net force on the center of mass, precession of the pericenter, and rotation of the orbital plane in the presence of an out-of-plane center-of-mass velocity, which persist even in a homogeneous isotropic environment due to intrinsic asymmetry. The interplay of self-acceleration, precession, and dynamical friction shifts the center of mass along an unwinding spiral. For supermassive black holes, this shift is predicted to dominate over Brownian wandering and reach the influence radius, implying a possible offset from the galaxy's center, expansion of the loss cone, and impact on the final parsec problem. It is also shown that eccentricity growth is universal, while circularization of binaries with small mass ratios is an artifact of cutting off long-lived encounters. These results enrich the model of binary hardening and are significant for populations of gravitational-wave sources.
Two black holes, orbiting each other, behave like a boat rowing with stars. Each passing star is flung away, like a stroke of an oar, and transfers momentum to the pair. For a long time, it was thought this simply brings the black holes closer. But new analysis has shown: by flinging stars unevenly, the system pushes itself sideways, spins, and tilts the orbit.
The reason is the shape of their path. The orbit is asymmetric, so the strokes are of different strength. The black holes begin to 'swim' away from the center of the galaxy, moving thousands of light-years away. This explains why supermassive black holes are sometimes found not at the center, and also changes their gravitational waves as they approach.
The most unexpected result: instead of damping, the orbit becomes increasingly elongated, like a lopsided oval. A similar orbital precession is seen in Mercury — explained by Albert Einstein — but here, instead of curved space, stellar 'oars' are at work.
🎯 A pair of black holes moves by flinging stars, like a boat rowing with oars.