A planetary system around the star can cause such perturbations, as can a binary star companion or the close approach of another star.

Gravitational forces from third bodies can cause perturbations to an orbit.

Solar radiation pressure causes perturbations to orbits.

Lightning can cause ionospheric perturbations in the D-region in one of two ways.

Similarly, mutations of genes (and thus their proteins) can cause perturbations of networks and thus disease.

These forces cause perturbations to the orbit, which change over time and which cannot be exactly calculated.

In addition, superfluids boil only at free surfaces, preventing the formation of bubbles on the surface of the cavity, which would cause mechanical perturbations.

In centimeter and meter-sized bodies, viscosity may cause significant perturbations that can change an orbit.

Extensive, massive deletion of this kind would necessarily cause major perturbations to cellular function and energetic equilibrium.

Episodic and chronic pollution of the environment by oil causes major ecological perturbations.