  In this paper, transient high energy events and their hosts are discussed
with focus on signatures of radio synchrotron emission. Outstanding questions
range from the origin of the two phases of radio emission in supernovae to the
formation of conical jets launched at relativistic velocities in active nuclei
to the formation of radio hotspots in FR II sources to the formation of radio
relics and halos in clusters of galaxies to the origin of the relativistic
electron population and its energy spectrum which is responsible for the
synchrotron emission to the composition of the radio synchrotron-emitting
plasma in these sources. Observations have helped build an empirical model of
active nuclei but the origin of the narrow line regions, broad line regions,
dust, accretion disk in active nuclei and their connection to radio jets and
lobes remains largely unknown. This paper attempts to understand and resolve
these. A few results are: 1 The matter ejected in a transient explosive events
have to be energised, before ejection, to escape velocity. An important source
of transient explosive energy in the universe is thermonuclear. The energy
spectrum of the particles energised in such events will follow a
normal/gaussian distribution ; 2 The prompt radio synchrotron emission from a
supernova is from a positron-electron plasma whereas the delayed radio
synchrotron from supernova remnants is due to the relativistic proton-electron
plasma mixed with the thermal plasma ; 3 Jets and narrow line gas are launched
from the polar regions of the pseudosurface of the rotating black hole in
active nuclei by the energy released in a thermonuclear outburst in the
accreted matter. Synchrotron jets are composed of positron-electron plasma.
