The mathematical problem of studying the positions and velocities of three mutually attracting bodies (such as the Sun, Earth and Moon) and the stability of their motion. This problem is surprisingly
difficult to solve, even in the simple case, called restricted three-body problem, where one of the masses is taken to be negligibly small so that the problem simplifies to finding the behavior of the mass-less body in the combined gravitational field of the other two.
The mathematical problem of studying the positions and velocities of three mutually attracting bodies (such as the Sun, Earth and Moon) and the stability of their motion. This problem is surprisingly
difficult to solve, even in the simple case, called restricted three-body problem, where one of the masses is taken to be negligibly small so that the problem simplifies to finding the behavior of the mass-less body in the combined gravitational field of the other two.
Velocity required to cause entrainment in the erosional agents of wind, water or ice. Threshold velocity is usually higher than the velocity required for transport because factors like particle cohesi
on. Also see critical entrainment velocity.
Is a form of localized unfrozen ground (talik) in an area of permafrost. It is open to the ground surface and to an area of unfrozen ground beneath it. Permafrost encases it along the sides.