(gravity much stronger than in the solar system such as near a black hole)
Strong-field gravity is gravity in the region of an
object of sufficient mass that the effects of general relativity (GR),
such as gravitational waves, are pronounced. The solar system
shows the effects of general relativity, but generally only
through very precise measurement. Near a black hole
or neutron star, these effects are striking
and Newtonian mechanics produce a very poor estimate at best.
Strong-field gravity physics is the study of
physical laws in this regime.