>Reminds me of the hubble picture of young star clusters bursting to life in the center of a pair of colliding galaxies. All those moving objects tend to cluster and the smaller objects merge...
Galaxy collisions are fairly common. The distance between galaxies is more or less similar in scale to the sizes of them galaxies (for comparison, collisions between stars are deemed rare, except perhaps close to the galaxy center).
Our own Milky Way may or may not have a collision in about 3e9 years, with the Andromeda Galaxy, which is quickly approaching. However, it may be moving directly towards us, or it may have a lateral movement - the movement towards us (or away from us, in other cases) is easy to establish with the Doppler Effect; the lateral component is more difficult to measure.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
