Dynamical friction

Under dynamic friction is generally understood as the influence of objects that do not touch and influence nevertheless by their movement - its dynamics.

This effect plays an important role in astronomy in the collision of galaxies (so-called merging ). There is no conflict, since it is very unlikely that a star impinges upon another. When penetration of star systems therefore occurs dynamic friction. When a star flies through other Sternsyteme, it exerts a force of attraction by its mass to the surrounding objects. This in turn leads to that the density is increased after the penetrating star, so that this is slowed down in its movement.

• Astrophysical process