**Publication date:** Jun 1983

**Abstract:**

Due to the present indications of the existence of a non-zero cosmological constant, some aspects of the influence of a Lambda not equal to zero on the character of test-particle motion in black-hole backgrounds are discussed. Equations of motion of electrically charged particles and magnetic monopoles are written in the most general Kerr-Newman-de Sitter dyon background. For the Kerr-de Sitter spacetime, the latitudinal motion is examined in detail by using the ‚Chinese boxes‘ technique. The radial motion in the Schwarzschild-de Sitter background is considered with attention devoted to the existence and stability of circular orbits and to the properties of purely radial trajectories. Finally, the possibility of constructing an Einstein-Strauss-de Sitter model of the Universe (i.e. a model of Schwarzschild-de Sitter condensations in the Friedman Universe with a non-zero Lambda-term) is discussed.

**Authors:**

Stuchlik, Z.;