The speed of shock fronts
exceeds the linear wave propagation but is less than the speed of the Riemann wave [1,26,30].
i,rise] of the incident shock front
from the following empirical relation 
In the case of a distant explosion the pressure signal of the reflected shock front
is described by the relation:
We are mainly concerned with a fast shock front
due to a strong nonlinear convection term induced by a strong vacuum, and the forms of D are, therefore, insignificant in the present investigation.
Nonetheless, the formation of a shock front
also marks a limit on the amount of energy that can be pumped into a sound wave.
Dr Andy Breen, a solar-terrestrial physicist, said the shock front
from the eruption was felt on Earth at 4am yesterday morning after being launched from the Sun about 11am the morning before.
At the time, theorists supposed that the matter in the supernova shock front
was too thick for the gamma rays themselves to get out.
Scientists want to understand how the acceleration of electrons in very strong shocks with large 'Mach numbers' depends on the angle between the magnetic field and a vector at right angles to the shock front
GERMAN legend Berti Vogts has emerged as the shock front
runner to replace Dick Advocaat at Rangers.
However, according to the theoretical models, at the time of the reported observations (July through September) the matter in the expanding supernova shock front
should still have been opaque to gamma rays.
It all hangs on the positive identification of the extra X-ray radiation as directly emerging from the supernova shock front
, rather than from the relativistic jets or central black hole.
As the solar wind from the sun flows out beyond Pluto, it collides with the material between the stars, forming a shock front