A new inclination instability reshapes Keplerian disks into cones:
  application to the outer Solar System
  Disks of bodies orbiting a much more massive central object are extremely
common in astrophysics. When the orbits comprising such disks are eccentric, we
show they are susceptible to a new dynamical instability. Gravitational forces
between bodies in the disk drive exponential growth of their orbital
inclinations and clustering in their angles of pericenter, expanding an
initially thin disk into a conical shape by giving each orbit an identical
'tilt' with respect to the disk plane. This new instability dynamically
produces the unusual distribution of orbits observed for minor planets beyond
Neptune, suggesting that the instability has shaped the outer Solar System. It
also implies a large initial disk mass (1-10 Earth masses) of scattered bodies
at hundreds of AU; we predict increasing numbers of detections of minor planets
clustered in their angles of pericenter with high inclinations.
