Over time, chance encounters between objects will perturb their orbits, sending some toward the center of the galaxy, and others out into the void.

As the wind blows, pressure and friction perturb the equilibrium of the water surface and transfer energy from the air to the water, forming waves.

When you take this model and you perturb it, you give it a push, as it bumps into something, it self stabilizes, with no brain or no reflexes, just by the structure alone.

Because it's very interesting. When you take this model and you perturb it, you give it a push, as it bumps into something, it self stabilizes, with no brain or no reflexes, just by the structure alone.

Let me add a personal note as the Chairman of COSPAR apos s Panel on Potentially Environmentally Detrimental Activities in Space We shall continue to keep a watchful eye on all developments in space that could potentially perturb our environment or that of our planetary neighbours.