N-body dynamics#

Direct-summation gravity in physicskit.astro.nbody: the sensitive dependence on initial conditions Poincare discovered in the three-body problem, the figure-eight choreography, the virial theorem, and the long-term stability that symplectic integration buys N-body simulation.

Poincare’s discovery: sensitive dependence in the three-body problem

Poincare's discovery: sensitive dependence in the three-body problem

The figure-eight three-body choreography

The figure-eight three-body choreography

Clausius’s virial theorem for a bound gravitational orbit

Clausius's virial theorem for a bound gravitational orbit

Symplectic integration and long-term N-body stability

Symplectic integration and long-term N-body stability