Arnold O. Benz

Theology in a dynamic universe

According to recent astrophysical evidence, the present universe has been forming for the past 14 billion years. New kinds of objects have emerged even recently. The reverse side of this creativity is the observed and predicted decay of all objects. Will new structures form in the future? This is a question of hope, which is not a scientific term but originates from experience on the level of personal and religious perceptions requiring participation. Anticipating the future, science and theology of creation meet, and the tension between practical knowledge and visionary hope enters a constructive dialogue.

Collisionless Shock Waves

A shock may be defined as a layer of rapid change propagating through the plasma. In its rest frame, the shock is approximately stationary in time and is marked by a rapid transition of parameters from the medium ahead (also called upstream) to the medium behind the shock (downstream). A simple example of a shock occurs when a plane piston moves at high velocity into a homogeneous plasma at rest. A shock develops ahead of the piston between the piled-up plasma and the undisturbed plasma. The shock propagates at a velocity similar to or higher velocity than that of the piston. Another example is a wave (or a pulse) with an amplitude so high that the wave velocity of the crest is faster than the velocity of the dip. Small disturbances thus travel faster on the wave crest, overtake it and add in front of it. The wave profile steepens in the front of the wave crest and develops into a shock (like an ocean wave approaching a sloping beach steepens and finally breaks).